Mar 11, 2017

Zika virus also may have harmful heart effects, research shows in first report in adults

In a study of nine adult patients with Zika and no previous history of cardiovascular disease, all but one developed a heart rhythm problem and two-thirds had evidence of heart failure.
Zika also may have serious effects on the heart, new research shows in the first study to report cardiovascular complications related to this virus, according to data being presented at the American College of Cardiology's 66th Annual Scientific Session.

In a study at the Institute of Tropical Medicine in Caracas, Venezuela, of nine adult patients with Zika and no previous history of cardiovascular disease, all but one developed a heart rhythm problem and two-thirds had evidence of heart failure.

It is known that Zika can cause microcephaly, a severe birth defect in babies born to women infected with the virus, and Guillain-Barré syndrome, a neurological condition that can lead to muscle weakness and, in severe cases, paralysis.

"We know that other mosquito-borne diseases, such as dengue fever and chikungunya virus, can affect the heart, so we thought we might see the same with Zika. But we were surprised by the severity, even in this small number of patients," says Karina Gonzalez Carta, M.D., cardiologist and research fellow at Mayo Clinic and the study's lead author.

The patients (six were female, and mean age was 47) were seen at the Department of Tropical Medicine in Venezuela within two weeks of having Zika-type symptoms. They reported symptoms of heart problems, most commonly palpitations followed by shortness of breath and fatigue. Only one patient had any previous cardiovascular problems (high blood pressure), and tests confirmed that all of the patients had active Zika infection. Patients underwent an initial electrocardiogram (EKG), a test that shows the electrical activity of the heart, and in eight of the patients, the EKG suggested heartbeat rate or rhythm concerns. These findings prompted a full cardiovascular workup using an echocardiogram, (24-hour) Holter monitor and a cardiac MRI study.

Serious arrhythmias were detected in eight patients: three cases of atrial fibrillation, two cases of nonsustained atrial tachycardia and two cases of ventricular arrhythmias. Heart failure was present in six cases. Of these, five patients had heart failure with low ejection fraction, when the heart muscle doesn't pump blood as well as it should, and one had heart failure with preserved ejection fraction, when the heart becomes stiff and cannot relax or fill properly.

The patients have been followed since July 2016, and none of their cardiac issues have resolved, but symptoms have improved following treatment for heart failure or atrial fibrillation, Dr. Carta says.

"Following this research, we want patients who are suffering from Zika symptoms also to be aware of the cardiac symptoms because they might not connect the two," Dr. Carta says. "The same is true for physicians because they might be focused on the Zika symptoms but not thinking about cardiac concerns."

Dr. Carta will present the study, "Myocarditis, Heart Failure and Arrhythmias in Patients With Zika," on Saturday, March 18, at 3:45 p.m. ET.

This study will be published simultaneously online in the Journal of the American College of Cardiology at the time of presentation.

Read more at Science Daily

Massive rogue waves aren't as rare as previously thought

This is a rogue wave photo taken from the deck of the RV Cape Henlopen in the western North Atlantic during the Atlantic Remote Sensing Land/Ocean Experiment (ARSLOE) The crest of the rogue propogates from the right to left. Credit: H. Mitsuyasu Inset figure: Surface elevation of groups in each period band displayed on axes of time and logarithm of period in seconds. All 32 periods are displayed and their sum (divided by 20) is graphed along the time axis. The Andrea crest is at 862 s.
University of Miami Rosenstiel School of Marine and Atmospheric Science scientist Mark Donelan and his Norwegian Meteorological Institute colleague captured new information about extreme waves, as one of the steepest ever recorded passed by the North Sea Ekofisk platforms in the early morning hours of Nov. 9 2007.

Within the first hour of the day, the Andrea wave passed by a four-point square array of ocean sensors designed by the researchers to measure the wavelength, direction, amplitude and frequency of waves at the ocean surface.

Using the information from the wave set -- a total of 13,535 individual waves -- collected by the system installed on a bridge between two offshore platforms, the researchers took the wave apart to examine how the components came together to produce such a steep wave.

The data from the 100-meter wide "wall of water" moving at 40 miles per hour showed that Andrea may have reached heights greater than the recorded height of 49 feet above mean sea level. They also found that rogue waves are not rare as previously thought and occur roughly twice daily at any given location in a storm. The findings showed that the steeper the waves are, the less frequent their occurrence, which is about every three weeks at any location for the steepest rogues.

The Andrea crest height was 1.63 times the significant height (average height of the one third highest waves). Optimal focusing of the Andrea wave showed that the crest could have been even higher and limited by breaking at 1.7 times the significant height. This establishes the greatest height rogues can reach for any given (or forecasted) significant height.

"Rogue waves are known to have caused loss of life as well as damage to ships and offshore structures," said Mark Donelan, professor emeritus of ocean sciences at the UM Rosenstiel School. "Our results, while representing the worst-case rogue wave forecast, are new knowledge important for the design and safe operations for ships and platforms at sea."

From Science Daily

Mar 10, 2017

Vision, not limbs, led fish onto land 385 million years ago

A side view of a 3-D model of Tiktaalik in a murky waterway in the Devonian, 385 million years ago, looking out above the water line through eyes set on top of the skull, and breathing through spiracles located just behind the eyes.
A provocative new Northwestern University and Claremont McKenna, Scripps and Pitzer colleges study suggests it was the power of the eyes and not the limbs that first led our ancient aquatic ancestors to make the momentous leap from water to land. Crocodile-like animals first saw easy meals on land and then evolved limbs that enabled them to get there, the researchers argue.

Neuroscientist and engineer Malcolm A. MacIver of Northwestern and evolutionary biologist and paleontologist Lars Schmitz of Claremont McKenna, Scripps and Pitzer colleges studied the fossil record and discovered that eyes nearly tripled in size before -- not after -- the water-to-land transition. The tripling coincided with a shift in location of the eyes from the side of the head to the top. The expanded visual range of seeing through air may have eventually led to larger brains in early terrestrial vertebrates and the ability to plan and not merely react, as fish do.

"Why did we come up onto land 385 million years ago? We are the first to think that vision might have something to do with it," said MacIver, professor of biomedical engineering and of mechanical engineering in the McCormick School of Engineering.

"We found a huge increase in visual capability in vertebrates just before the transition from water to land. Our hypothesis is that maybe it was seeing an unexploited cornucopia of food on land -- millipedes, centipedes, spiders and more -- that drove evolution to come up with limbs from fins," MacIver said. (Invertebrates came onto land 50 million years before our vertebrate ancestors made that transition.)

The enlargement of eyes is significant. By just popping those eyes above the water line, the fish could see 70 times farther in air than in water. With the tripling of eye size, the animal's visually monitored space increased a millionfold. This happened millions of years before fully terrestrial animals existed.

"Bigger eyes are almost worthless in water because vision is largely limited to what's directly in front of the animal," said Schmitz, assistant professor of biology at the W.M. Keck Science Department, a joint program of Claremont McKenna, Scripps and Pitzer colleges.

"But larger eye size is very valuable when viewing through air. In evolution, it often comes down to a trade-off. Is it worth the metabolic toll to enlarge your eyes? What's the point? Here we think the point was to be able to search out prey on land," he said.

Larger eyes were consequently selected for, whereas the study shows that in water, larger eyes led to negligible increases in visual range. In fact, one animal group that arose after animals came onto land went back to full-time life underwater, and their eyes went back to the smaller eye size normally seen in fish, MacIver and Schmitz found.

The study, "Massive Increase in Visual Range Preceded the Origin of Terrestrial Vertebrates," was published today (March 7) by the journal Proceedings of the National Academy of Sciences (PNAS).

The massive increase in visual capability enabled by vision in air likely allowed early-limbed animals to evolve more complex cognition. These animals were no longer forced to react with split-second speed as was required by life in the vision-limiting water. Eventually, the researchers said, evolution led to the human capability of prospective cognition: the power to weigh options for the future and to choose strategically.

MacIver and Schmitz studied 59 fossil specimens spanning the time before the water-to-land transition, during the transition and after the transition. Their computer simulations of the animals' visual environments (such as clear or murky water in the daytime or above water in the daytime and the nighttime) show that the benefit of increased eye size would be realized when an animal is seeing through air, not water.

The researchers measured the size of each fossil's orbits, or eye sockets, and head length. From that, they determined the size of the eyes and the size of the animal itself. They found that before the water-to-land transition the average orbit size was 13 millimeters and around the time of transition the average size was 36 millimeters.

Read more at Science Daily

Can tree rings predict volcanic eruptions?

The basalt from the 2002/2003 eruption of Mount Etna covered parts of the forest.
Scientists made a surprising discovery on their mission to find better indicators for impending volcanic eruptions: it looks like tree rings may be able to predict eruptions, report the Swiss Federal Institute for Forest, Snow and Landscape Research WSL and the ETH Zurich.

Nicolas Houlié, a geophysicist at ETH Zurich, first came to know about this potential early warning system in 2001. While looking at a satellite image, he noticed a three kilometres long green line on the north-east flank of Mount Etna. The line reflects the Normalised Difference Vegetation Index (NDVI): the higher the value, the more vegetation is thriving in the area. But what made the discovery really astonishing is the fact that the volcano erupted along that exact line just one year later.

Volcanologists and dendrochronologists join forces

Dendrochronologists agree that NDVI values are connected to tree growth, and thus reflected in tree-ring width. With that in mind, geographer Ruedi Seiler, a PhD student at WSL, and dendrologist Paolo Cherubini, Head of Dendrochronology at WSL, teamed up with Nicolas Houlié four years ago to embark upon a cross-disciplinary research project funded by the Swiss National Science Foundation. Their unusual idea -- namely that tree rings give information about volcanic processes prior to eruptions -- has now been published in the journal Scientific Reports.

The rings formed in tree trunks during trees' growth periods are valuable repositories of environmental information: the ring width reflects the tree's growth conditions, which are a combination of the temperature, precipitation and nutrient conditions during a given growing season. "The ring width may also be influenced by volcanic activity on Mount Etna and in other volcanic regions," speculates Seiler.

Short pre-eruptive phase?

Under Cherubini's direction, the researchers conducted their initial fieldwork alongside the lava flows that ran down Mount Etna's west flank in January 1974. This was the location where Italian researchers also spotted an anomaly on satellite images in 1973, prior to the eruption.

Seiler took over fifty tree samples in the aim of identifying any pre-eruptive signals in the tree rings. However, the researchers found that the tree rings for summer 1973 were neither exceptionally wide nor exceptionally narrow.

"If volcanic activity does influence tree rings, then the pre-eruptive phase of the 1974 eruption can only have begun when the trees had already ceased their seasonal growth," concludes Seiler. That said, the calculated duration of the pre-eruptive phase -- which would be just a few months in this case -- is actually consistent with the results of earlier geochemical and geophysical studies.

Restricted growth following an eruption

Although there were no changes to the trees' growth before the 1974 eruption, the researchers' article in Scientific Reports points out that the trees grew less in the two summers following the eruption than in other years. "I see great potential in this observation: we may be able to use tree rings to reliably date minor flank eruptions," says volcanologist Houlié. This is significant because a volcano's past behaviour can provide information about its future activities and thus contribute to improving measures to protect the population.

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Gene found to cause sudden death in young people

Identifying the gene responsible for arrhythmogenic right ventricle cardiomyopathy (ARVC) in young people is important because it helps to clarify the genetic mechanisms underlying ARVC, and it also makes the early detection of ARVC possible in otherwise unsuspecting people.
Researchers from Canada, South Africa and Italy have identified a new gene that can lead to sudden death among young people and athletes.

The gene, called CDH2, causes arrhythmogenic right ventricle cardiomyopathy (ARVC), which is a genetic disorder that predisposes patients to cardiac arrest and is a major cause of unexpected death in seemingly healthy young people.

The discovery, published in Circulation: Cardiovascular Genetics, is the result of international collaboration that began 15 years ago. It is led by a South African team headed by Bongani Mayosi, a professor of cardiology at the University of Cape Town and Groote Schuur Hospital, along with researchers of the Italian Auxologico Institute of Milan and the University of Pavia. A team of investigators from the Population Health Research Institute of McMaster University and Hamilton Health Sciences, led by Dr. Guillaume Paré, performed the genetic sequencing, as well as the bioinformatics analysis for the study.

"This is important news for families who have had a young family member suffer a sudden cardiac death, for them to know a genetic cause has been identified," said Paré, who is an associate professor of pathology and molecular medicine with the Michael G. DeGroote School of Medicine.

"Our team was happy to contribute to the finding that a mutation in CDH2 is the underlying culprit in a portion of these patients. This will pave the way for preventative interventions and genetic counselling."

According to the Heart and Stroke Foundation of Canada, there are about 40,000 cardiac arrests in Canada each year, and less than one in 10 people are estimated to survive a cardiac arrest that happens outside of a hospital.

Inherited forms of cardiomyopathy often cause sudden cardiac arrest death in young people under the age of 35. In ARVC, the heart tissue is replaced by fatty and fibrous tissue. This process encourages the development of cardiac arrhythmias such as tachycardia and ventricular fibrillation, which cause loss of consciousness and cardiac arrest. In the case of ventricular fibrillation, without a ready electrical defibrillation, it causes sudden death in a few minutes.

For 20 years, Mayosi followed a South African family affected by ARVC that had experienced several cases of juvenile sudden death. Excluding all genetic causes known at the time, the Italian researchers sequenced all the coding regions of the genome in two ill members of the family. The genetic mutation responsible for the disease in the family, CDH2, was narrowed down from more than 13,000 common genetic variants present in the two ill patients.

CDH2 is responsible for the production of Cadherin 2 or N-Cadherin, a key protein for normal adhesion between the cardiac cells. The gene's discovery was validated by finding a second mutation on the same gene in another patient with ARVC from a different family. It was known from previous studies that genetically modified mice without this protein tend to have malignant ventricular arrhythmias and sudden death.

The researchers said identifying the gene is important because it helps to clarify the genetic mechanisms underlying ARVC, and it also makes the early detection of ARVC possible in otherwise unsuspecting people.

Read more at Science Daily

First public data released by hyper suprime-cam Subaru Strategic Program

This is a HSC-SSP image of a massive cluster of galaxies in the Virgo constellation showing numerous strong gravitational lenses. The distance to the central galaxy is 5.3 billion light years, while the lensed galaxies, apparent as the arcs around the cluster, are much more distant. This is a composite image in the g, r, and i band, and has a spatial resolution of about 0.6 arcseconds.
The first massive data set of a "cosmic census" has been released using the largest digital camera on the Subaru Telescope. With its beautiful images now available for the public at large, figuring out the fate of the Universe has come one step closer.

Data from the Hyper Suprime-Cam Subaru Strategic Program (HSC-SSP) was released to the public on February 27th, 2017. HSC-SSP is a large survey being done using HSC, an optical imaging camera mounted at the prime focus of the Subaru Telescope. Since it is difficult to search such a huge dataset with standard tools, the National Astronomical Observatory of Japan (NAOJ) has developed a dedicated database and interface for ease of access and use of the data.

NAOJ embarked on the HSC-SSP survey in collaboration with the Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU) in Japan, the Academia Sinica Institute of Astronomy and Astrophysics (ASIAA) in Taiwan, and Princeton University in the United States. The project will survey 300 nights over 5 to 6 years. This survey consists of three layers: Wide, Deep, and UltraDeep, using optical and near infrared wavelengths in five broad bands (g, r, i, z, y) and four narrow-band filters.

This first public dataset already contains almost 100 million galaxies and stars. It demonstrates that HSC-SSP is making the most from the performance of the Subaru Telescope and HSC. In contrast, the US-based Sloan Digital Sky Survey (SDSS) -- which is known for its wide area observation and equivalent data sets -- took over 10 years to establish. The total amount of data taken so far by the HSC-SSP, meanwhile, comprises 80 terabytes, which is comparable to the size of about 10 million images by a general digital camera.

This release includes data from the first 1.7 years (61.5 nights of observations beginning in 2014). The observed areas covered by the Wide, Deep, and UltraDeep layers are 108, 26, and 4 square degrees, respectively. The limiting magnitudes, which refer to the depth of the observations, are 26.4, 26.6 and 27.3 mag in r-band (about 620 nm wavelength), respectively, allowing observations of some of the most distant galaxies in the Universe.

In multi-band images, the images are extremely sharp, with only 0.6 to 0.8 arcseconds across for point-like objects like stars. One arcsecond equals 3600th part of a degree. The high-quality data will allow an unprecedented view into the nature and evolution of galaxies and dark matter.

"Since 2014, we have been observing the sky with HSC, which can capture a wide-field image with high resolution," said NAOJ Professor Satoshi Miyazaki, the leader of the HSC-SSP. "We believe the data release will lead to many exciting astronomical results, including exploring the nature of dark matter and dark energy, as well as asteroids in our own solar system objects, and galaxies in the Early Universe. SSP team members are now preparing a number of scientific papers based on the data. We plan to publish them in a special issue of the Publications of the Astronomical Society of Japan. Moreover, we hope that interested members of the public will access the data and enjoy the real Universe imaged by the Subaru telescope, one of the largest of its kind in the world."

Kavli IPMU Director Hitoshi Murayama added: "When we consider the future of Japan, we must use data from the census to see how quickly the population is aging. Similarly, when we consider the evolution and destiny of the Universe, it pays to take a "census" of it. Which is to say, it is necessary to observe a large number of celestial bodies over a wide distance and range and to analyze enormous amounts of data. It is for this purpose that the HSC digital camera -- which has one of the world's largest telescope with a wide field of vision -- was created.

"Kavli IPMU contributed to the design of its optical systems, including its huge and special lens of about 1m in size, the production of casings that do not deform under the harsh climatic conditions of a mountain summit, and a machine control system that controls its 3m camera at the micron level. In this way, the census can take images that would take thousands of years with the Hubble Space Telescope, but in a few years. As a result, the HSC has come closer still to unraveling the fate of the Universe. So I am very excited about the future use of this data.

"Furthermore, after 2020, we plan to investigate in more detail celestial objects photographed by the HSC, using the Prime Focus Spectrograph (PFS) currently under construction, which is part of the Subaru Measurement of Images and Redshifts (SuMIRe) project. We look forward to its future development and the data emanating from SuMIRe."

Read more at Science Daily

Mar 9, 2017

Aboriginal hair shows 50,000 year connection to Australia

Modern Aboriginal Australians are the descendants of a single founding population that arrived in Australia 50,000 years ago, while Australia was still connected to New Guinea. Populations then spread rapidly -- within 1500-2000 years -- around the east and west coasts of Australia, meeting somewhere in South Australia.
DNA in hair samples collected from Aboriginal people across Australia in the early to mid-1900s has revealed that populations have been continuously present in the same regions for up to 50,000 years -- soon after the peopling of Australia.

Published in the journal Nature, the findings reinforce Aboriginal communities' strong connection to country and represent the first detailed genetic map of Aboriginal Australia prior to the arrival of Europeans.

These are the first results from the Aboriginal Heritage Project, led by the University of Adelaide's Australian Centre for Ancient DNA (ACAD) in partnership with the South Australian Museum.

Researchers analysed mitochondrial DNA from 111 hair samples that were collected during a series of remarkable anthropological expeditions across Australia from 1928 to the 1970s and are part of the South Australian Museum's unparalleled collection of hair samples.

Mitochondrial DNA allows tracing of maternal ancestry, and the results show that modern Aboriginal Australians are the descendants of a single founding population that arrived in Australia 50,000 years ago, while Australia was still connected to New Guinea. Populations then spread rapidly -- within 1500-2000 years -- around the east and west coasts of Australia, meeting somewhere in South Australia.

"Amazingly, it seems that from around this time the basic population patterns have persisted for the next 50,000 years -showing that communities have remained in discrete geographical regions," says project leader Professor Alan Cooper, Director of ACAD, University of Adelaide.

"This is unlike people anywhere else in the world and provides compelling support for the remarkable Aboriginal cultural connection to country. We're hoping this project leads to a rewriting of Australia's history texts to include detailed Aboriginal history and what it means to have been on their land for 50,000 years -- that's around 10 times as long as all of the European history we're commonly taught."

A central pillar of the Aboriginal Heritage Project is that Aboriginal families and communities have been closely involved with the project from its inception and that analyses are only conducted with their consent. Importantly, results are first discussed with the families to get Aboriginal perspectives before scientific publication. The research model was developed under the guidance of Aboriginal elders, the Genographic Project, and professional ethicists.

This is the first phase of a decade-long project that will allow people with Aboriginal heritage to trace their regional ancestry and reconstruct family genealogical history, and will also assist with the repatriation of Aboriginal artefacts.

"Aboriginal people have always known that we have been on our land since the start of our time," says Kaurna Elder Mr Lewis O'Brien, who is one of the original hair donors and has been on the advisory group for the study. "But it is important to have science show that to the rest of the world. This is an exciting project and we hope it will help assist those of our people from the Stolen Generation and others to reunite with their families."

"Reconstructing the genetic history of Aboriginal Australia is very complicated due to past government policies of enforced population relocation and child removal that have erased much of the physical connection between groups and geography in Australia today," says Dr Wolfgang Haak, formerly at ACAD and now at the Max Planck Institute for the Science of Human History in Germany.

The South Australian Museum's collection of hair samples, complete with rich cultural, linguistic, genealogical and geographical data, comes from the expeditions run by the Board of Anthropological Research from the University of Adelaide.

"This Aboriginal Heritage Project is able to exist because of the extensive records collected by Norman Tindale and Joseph Birdsell and others on those expeditions, which are held in trust for all at the South Australian Museum. They include detailed information about the birthplaces, family history and family trees, film, audio and written records -- allowing a wide range of approaches to be used by this project to reconstruct history," says Brian Oldman, Director of the South Australian Museum.

"The South Australian Museum's Aboriginal Family History Unit has also been instrumental to the project and has worked closely with the University team to consult with Aboriginal families and communities to obtain permission for tests to be performed," he says.

Professor Cooper says: "We are very grateful for the enthusiasm and overwhelming support for this project we have received from Aboriginal families, and the Cherbourg, Koonibba, and Point Pearce communities in particular."

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Discovery of widespread platinum may help solve Clovis people mystery

University of South Carolina archaeologists found an abundance of platinum -- an element associated with cosmic objects like asteroids or comet -- at 11 Clovis excavation sites across the United States.
No one knows for certain why the Clovis people and iconic beasts -- mastodon, mammoth and saber-toothed tiger -- living some 12,800 years ago suddenly disappeared. However, a discovery of widespread platinum at archaeological sites across the United States by three University of South Carolina archaeologists has provided an important clue in solving this enduring mystery.

The research findings are outlined in a new study in Scientific Reports, a publication of Nature. The study, authored by 10 researchers, builds on similar findings of platinum -- an element associated with cosmic objects like asteroids or comets -- found by Harvard University researchers in an ice-core from Greenland in 2013.

The South Carolina researchers found an abundance of platinum in soil layers that coincided with the "Younger-Dryas," a climatic period of extreme cooling that began around 12,800 ago and lasted about 1,400 years. While the brief return to ice-age conditions during the Younger-Dryas has been well-documented by scientists, the reasons for it and the demise of the Clovis people and animals have remained unclear.

"Platinum is very rare in Earth's crust, but it is common in asteroids and comets," says Christopher Moore, the study's lead author. He calls the presence of platinum found in the soil layers at 11 archaeological sites in California, Arizona, New Mexico, Ohio, Virginia, North Carolina and South Carolina an anomaly.

"The presence of elevated platinum in archaeological sites is a confirmation of data previously reported for the Younger-Dryas onset several years ago in a Greenland ice-core. The authors for that study concluded that the most likely source of such platinum enrichment was from the impact of an extraterrestrial object," Moore says.

"Our data show that this anomaly is present in sediments from U.S. archaeological sites that date to the start of the Younger-Dryas event. It is continental in scale -- possibly global -- and it's consistent with the hypothesis that an extraterrestrial impact took place."

He says the Younger-Dryas coincides with the end of Clovis culture and the extinction of more than 35 species of ice-age animals. Moore says while evidence has shown that some of the animals were on the decline before Younger-Dryas, virtually none are found after it.

Moore says that would indicate an extinction event for North America.

He also says the platinum anomaly is similar to the well-documented finding of iridium, another element associated with cosmic objects, that scientists have found in the rock layers dated 65 million years ago from an impact that caused dinosaur extinction. That event is commonly known as Cretaceous-Tertiary or K-Pg by scientists.

"In both cases, the anomalies represent the atmospheric fallout of rare elements resulting from an extraterrestrial impact," Moore says.

He says the K-Pg dinosaur extinction was the result of a very large asteroid impact while the Younger-Dryas onset impact is likely the result of being hit by fragments of a much smaller sized comet or asteroid, possibly measuring up to two-thirds a mile in diameter.

"Another difference is that the Younger-Dryas impact event is not yet associated with any known impact crater," Moore says. "This may be because the fragments of the large object struck the glacial ice-sheet or exploded in the atmosphere. Several candidate craters are under investigation but have not been confirmed."

Moore says while his team's data does not contradict the Young-Dryas impact hypothesis, it also does not explain the likely effects that such an impact could have had on the environment, Paleoindians or ice-age animals.

Contributing to the study is Moore's university colleagues Mark Brooks, a geo-archaeologist who conducts research and excavations at the Savannah River Site, and archaeologist Albert Goodyear, who has spent decades documenting Clovis culture at the famed Topper site. Topper, located in Allendale County, South Carolina, along the banks of the Savannah River, is considered one of the most pristine U.S. sites for research on Clovis, one of the earliest ancient people.

Goodyear's work with Moore builds on research in which he found traces of extraterrestrial elements, including iridium, at the Younger-Dryas layer at Topper that was published in the Proceedings of the National Academy of Sciences in 2012.

Moore, Goodyear and Brooks conduct research through the South Carolina Institute of Anthropology and Archaeology in the university's College of Arts and Sciences.

In addition to Topper, the remaining 10 archaeological sites that Moore, Goodyear and others on their team conducted research in 2016 included Arlington Canyon on Santa Rosa Island, California; Murray Springs, Arizona; Blackwater Draw, New Mexico; Sheriden Cave, Ohio; Squires Ridge and Barber Creek, North Carolina; and Kolb, Flamingo Bay, John Bay and Pen Point, South Carolina.

Read more at Science Daily

Hubble dates black hole's last big meal

This illustration shows the light of several distant quasars piercing the northern half of the Fermi Bubbles, an outflow of gas expelled by our Milky Way galaxy's hefty black hole. The Hubble Space Telescope probed the quasars' light for information on the speed of the gas and whether the gas is moving toward or away from Earth. Based on the material's speed, the research team estimated that the bubbles formed from an energetic event between 6 million and 9 million years ago. The inset diagram at bottom left shows the measurement of gas moving toward and away from Earth, indicating the material is traveling at a high velocity. Hubble also observed light from quasars that passed outside the northern bubble. The box at upper right reveals that the gas in one such quasar's light path is not moving toward or away from Earth. This gas is in the disk of the Milky Way and does not share the same characteristics as the material probed inside the bubble.
For the supermassive black hole at the center of our Milky Way galaxy, it's been a long time between dinners. NASA's Hubble Space Telescope has found that the black hole ate its last big meal about 6 million years ago, when it consumed a large clump of infalling gas. After the meal, the engorged black hole burped out a colossal bubble of gas weighing the equivalent of millions of suns, which now billows above and below our galaxy's center.

The immense structures, dubbed the Fermi Bubbles, were first discovered in 2010 by NASA's Fermi Gamma-ray Space Telescope. But recent Hubble observations of the northern bubble have helped astronomers determine a more accurate age for the bubbles and how they came to be.

"For the first time, we have traced the motion of cool gas throughout one of the bubbles, which allowed us to map the velocity of the gas and calculate when the bubbles formed," said lead researcher Rongmon Bordoloi of the Massachusetts Institute of Technology in Cambridge. "What we find is that a very strong, energetic event happened 6 million to 9 million years ago. It may have been a cloud of gas flowing into the black hole, which fired off jets of matter, forming the twin lobes of hot gas seen in X-ray and gamma-ray observations. Ever since then, the black hole has just been eating snacks."

The new study is a follow-on to previous Hubble observations that placed the age of the bubbles at 2 million years old.

A black hole is a dense, compact region of space with a gravitational field so intense that neither matter nor light can escape. The supermassive black hole at the center of our galaxy has compressed the mass of 4.5 million sun-like stars into a very small region of space.

Material that gets too close to a black hole is caught in its powerful gravity and swirls around the compact powerhouse until it eventually falls in. Some of the matter, however, gets so hot it escapes along the black hole's spin axis, creating an outflow that extends far above and below the plane of a galaxy.

The team's conclusions are based on observations by Hubble's Cosmic Origins Spectrograph (COS), which analyzed ultraviolet light from 47 distant quasars. Quasars are bright cores of distant active galaxies.

Imprinted on the quasars' light as it passes through the Milky Way bubble is information about the speed, composition, and temperature of the gas inside the expanding bubble.

The COS observations measured the temperature of the gas in the bubble at approximately 17,700 degrees Fahrenheit. Even at those sizzling temperatures, this gas is much cooler than most of the super-hot gas in the outflow, which is 18 million degrees Fahrenheit, seen in gamma rays. The cooler gas seen by COS could be interstellar gas from our galaxy's disk that is being swept up and entrained into the super-hot outflow. COS also identified silicon and carbon as two of the elements being swept up in the gaseous cloud. These common elements are found in most galaxies and represent the fossil remnants of stellar evolution.

The cool gas is racing through the bubble at 2 million miles per hour. By mapping the motion of the gas throughout the structure, the astronomers estimated that the minimum mass of the entrained cool gas in both bubbles is equivalent to 2 million suns. The edge of the northern bubble extends 23,000 light-years above the galaxy.

"We have traced the outflows of other galaxies, but we have never been able to actually map the motion of the gas," Bordoloi said. "The only reason we could do it here is because we are inside the Milky Way. This vantage point gives us a front-row seat to map out the kinematic structure of the Milky Way outflow."

The new COS observations build and expand on the findings of a 2015 Hubble study by the same team, in which astronomers analyzed the light from one quasar that pierced the base of the bubble.

"The Hubble data open a whole new window on the Fermi Bubbles," said study co-author Andrew Fox of the Space Telescope Science Institute in Baltimore, Maryland. "Before, we knew how big they were and how much radiation they emitted; now we know how fast they are moving and which chemical elements they contain. That's an important step forward."

The Hubble study also provides an independent verification of the bubbles and their origin, as detected by X-ray and gamma-ray observations.

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Convergent con artists: How rove beetles keep evolving into army ant parasites

This image shows a symbiotic Ecitophya simulans rove beetle (foreground) walking alongside its lookalike army host ant, Eciton burchellii (left). The ant has a large round head, whereas the beetle has a flatter head.
Marauding across the tropical forest floor, aggressive army ant colonies harbor hidden enemies within their ranks. The impostors look and smell like army ants, march with the ants, and even groom the ants. But far from being altruistic nest-mates, these creatures are parasitic beetles, engaged in a game of deception. Through dramatic changes in body shape, behavior, and pheromone chemistry, the beetles gain their hostile hosts' acceptance, duping the ants so they can feast on the colony brood.

This phenomenon did not evolve just once. Instead, these beetles arose at least a dozen separate times from non-ant-like ancestors. This discovery, published March 9 in Current Biology, provides evidence that evolution has the capacity to repeat itself in an astonishingly predictable way.

"These beetles represent a new and really stunning system of convergent evolution," says study co-author and evolutionary biologist Joseph Parker (@pselaphinae) of Columbia University and the American Museum of Natural History. "It's an elaborate symbiosis, which has evolved in a stereotyped way, multiple times from free-living ancestors."

The ant-mimicking beetles all belong to the Staphylinidae, or rove beetles, but don't mistake them for close relatives: the last common ancestor of the beetles in the study lived 105 million years ago, at about the time that humans split from mice. "What's exceptional is that this convergent system is evolutionarily ancient," says Parker. Although most other convergent systems, such as Darwin's finches, three-spined stickleback, and African lake cichlid fish, are a few million years old at most, this newly discovered example extends back into the Early Cretaceous.

Given this great age, Parker and his co-author Munetoshi Maruyama of the Kyushu University Museum argue that their finding challenges Stephen J. Gould's hypothesis that if time could be rewound and evolution allowed to replay again, very different forms of life would emerge. "The tape of life has been extremely predictable whenever rove beetles and army ants have come together," says Parker. "It begs the question: why has evolution followed this path so many times?"

Parker and Maruyama propose that although it's impossible that the beetles' most recent common ancestor was an army ant doppelganger, it probably possessed traits that would allow its descendants to readily evolve into army ant parasites. Free-living rove beetles are armed with glands that secrete defensive chemicals, so a beetle encountering an ant troop stands a much better chance of surviving than most insects do. And since rove beetles are predators, the brood of an army ant colony is an attractive food source. These traits, along with the rove beetle's body plan -- flexible and able to readily evolve into an ant-like shape to deceive hosts -- enabled the beetles to repeatedly infiltrate army ant societies.

"There's been this explosion of ants over the past 50-60 million years that must have radically changed terrestrial ecosystems," says Parker. "Army ants were part of that. They presented this huge niche for exploitation that these beetles were equipped to exploit, and they did so multiple times in parallel."

The paper itself focuses on DNA sequencing and reconstructing evolutionary history, but a decade of fieldwork went into collecting the beetle specimens for the study. Maruyama and Parker spent many hours in tropical forests, searching for beetles. "If you watch one of these army ant colonies for long enough, maybe one in every five thousand ants that wander past will be one of these beetles," says Parker. "You've got to have eagle eyes to pick them out."

The study opens up many questions about how this convergent system arose, some of which the researchers are starting to address by sequencing whole genomes of the rove beetles. "How predictable has molecular evolution been in each of these convergent beetle lineages? That's an obvious next step that could reveal genes involved in the ant-beetle symbiosis," says Parker.

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Mar 8, 2017

Dental plaque DNA shows Neanderthals used 'aspirin'

El Sidron upper jaw: a dental calculus deposit is visible on the rear molar (right) of this Neandertal. This individual was eating poplar, a source of aspirin, and had also consumed moulded vegetation including Penicillium fungus, source of a natural antibiotic.
Ancient DNA found in the dental plaque of Neandertals -- our nearest extinct relative -- has provided remarkable new insights into their behaviour, diet and evolutionary history, including their use of plant-based medicine to treat pain and illness.

Published today in the journal Nature, an international team led by the University of Adelaide's Australian Centre for Ancient DNA (ACAD) and Dental School, with the University of Liverpool in the UK, revealed the complexity of Neandertal behaviour, including dietary differences between Neandertal groups and knowledge of medication.

"Dental plaque traps microorganisms that lived in the mouth and pathogens found in the respiratory and gastrointestinal tract, as well as bits of food stuck in the teeth -- preserving the DNA for thousands of years," says lead author Dr Laura Weyrich, ARC Discovery Early Career Research Fellow with ACAD.

"Genetic analysis of that DNA 'locked-up' in plaque, represents a unique window into Neandertal lifestyle -- revealing new details of what they ate, what their health was like and how the environment impacted their behaviour."

The international team analysed and compared dental plaque samples from four Neandertals found at the cave sites of Spy in Belgium and El Sidrón in Spain. These four samples range from 42,000 to around 50,000 years old and are the oldest dental plaque ever to be genetically analysed.

"We found that the Neandertals from Spy Cave consumed woolly rhinoceros and European wild sheep, supplemented with wild mushrooms," says Professor Alan Cooper, Director of ACAD. "Those from El Sidrón Cave on the other hand showed no evidence for meat consumption, but appeared instead to have a largely vegetarian diet, comprising pine nuts, moss, mushrooms and tree bark -- showing quite different lifestyles between the two groups."

"One of the most surprising finds, however, was in a Neandertal from El Sidrón, who suffered from a dental abscess visible on the jawbone. The plaque showed that he also had an intestinal parasite that causes acute diarrhoea, so clearly he was quite sick. He was eating poplar, which contains the pain killer salicylic acid (the active ingredient of aspirin), and we could also detect a natural antibiotic mould (Penicillium) not seen in the other specimens."

"Apparently, Neandertals possessed a good knowledge of medicinal plants and their various anti-inflammatory and pain-relieving properties, and seem to be self-medicating. The use of antibiotics would be very surprising, as this is more than 40,000 years before we developed penicillin. Certainly our findings contrast markedly with the rather simplistic view of our ancient relatives in popular imagination."

Neandertals, ancient and modern humans also shared several disease-causing microbes, including the bacteria that cause dental caries and gum disease. The Neandertal plaque allowed reconstruction of the oldest microbial genome yet sequenced -- Methanobrevibacter oralis, a commensal that can be associated with gum disease. Remarkably, the genome sequence suggests Neandertals and humans were swapping pathogens as recently as 180,000 years ago, long after the divergence of the two species.

The team also noted how rapidly the oral microbial community has altered in recent history. The composition of the oral bacterial population in Neandertals and both ancient and modern humans correlated closely with the amount of meat in the diet, with the Spanish Neandertals grouping with chimpanzees and our forager ancestors in Africa. In contrast, the Belgian Neandertal bacteria were similar to early hunter gatherers, and quite close to modern humans and early farmers.

"Not only can we now access direct evidence of what our ancestors were eating, but differences in diet and lifestyle also seem to be reflected in the commensal bacteria that lived in the mouths of both Neandertals and modern humans," says Professor Keith Dobney, from the University of Liverpool.

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Scientists create new form of matter, a time crystal

Researchers have created the world's first time crystal, an exotic state of matter that combines the rigidity of an ordinary crystal with a regular rhythm in time.
Salt, snowflakes and diamonds are all crystals, meaning their atoms are arranged in 3-D patterns that repeat. Today scientists are reporting in the journal Nature on the creation of a phase of matter, dubbed a time crystal, in which atoms move in a pattern that repeats in time rather than in space.

The atoms in a time crystal never settle down into what's known as thermal equilibrium, a state in which they all have the same amount of heat. It's one of the first examples of a broad new class of matter, called nonequilibrium phases, that have been predicted but until now have remained out of reach. Like explorers stepping onto an uncharted continent, physicists are eager to explore this exotic new realm.

"This opens the door to a whole new world of nonequilibrium phases," says Andrew Potter, an assistant professor of physics at The University of Texas at Austin. "We've taken these theoretical ideas that we've been poking around for the last couple of years and actually built it in the laboratory. Hopefully, this is just the first example of these, with many more to come."

Some of these nonequilibrium phases of matter may prove useful for storing or transferring information in quantum computers.

Potter is part of the team led by researchers at the University of Maryland who successfully created the first time crystal from ions, or electrically charged atoms, of the element ytterbium. By applying just the right electrical field, the researchers levitated 10 of these ions above a surface like a magician's assistant. Next, they whacked the atoms with a laser pulse, causing them to flip head over heels. Then they hit them again and again in a regular rhythm. That set up a pattern of flips that repeated in time.

Crucially, Potter noted, the pattern of atom flips repeated only half as fast as the laser pulses. This would be like pounding on a bunch of piano keys twice a second and notes coming out only once a second. This weird quantum behavior was a signature that he and his colleagues predicted, and helped confirm that the result was indeed a time crystal.

The team also consists of researchers at the National Institute of Standards and Technology, the University of California, Berkeley and Harvard University, in addition to the University of Maryland and UT Austin.

Frank Wilczek, a Nobel Prize-winning physicist at the Massachusetts Institute of Technology, was teaching a class about crystals in 2012 when he wondered whether a phase of matter could be created such that its atoms move in a pattern that repeats in time, rather than just in space.

Potter and his colleague Norman Yao at UC Berkeley created a recipe for building such a time crystal and developed ways to confirm that, once you had built such a crystal, it was in fact the real deal. That theoretical work was announced publically last August and then published in January in the journal Physical Review Letters.

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Ancient stardust sheds light on the first stars

This artist's impression shows what the very distant young galaxy A2744_YD4 might look like. Observations using ALMA have shown that this galaxy, seen when the Universe was just 4 percent of its current age, is rich in dust. Such dust was produced by an earlier generation of stars and these observations provide insights into the birth and explosive deaths of the very first stars in the Universe.
An international team of astronomers, led by Nicolas Laporte of University College London, have used the [Atacama Large Millimeter/submillimeter Array (ALMA -- to observe A2744_YD4, the youngest and most remote galaxy ever seen by ALMA. They were surprised to find that this youthful galaxy contained an abundance of interstellar dust -- dust formed by the deaths of an earlier generation of stars.

Follow-up observations using the X-shooter instrument on ESO's [Very Large Telescope] confirmed the enormous distance to A2744_YD4. The galaxy appears to us as it was when the Universe was only 600 million years old, during the period when the first stars and galaxies were forming.

"Not only is A2744_YD4 the most distant galaxy yet observed by ALMA," comments Nicolas Laporte, "but the detection of so much dust indicates early supernovae must have already polluted this galaxy."

Cosmic dust is mainly composed of silicon, carbon and aluminium, in grains as small as a millionth of a centimetre across. The chemical elements in these grains are forged inside stars and are scattered across the cosmos when the stars die, most spectacularly in supernova explosions, the final fate of short-lived, massive stars. Today, this dust is plentiful and is a key building block in the formation of stars, planets and complex molecules; but in the early Universe -- before the first generations of stars died out -- it was scarce.

The observations of the dusty galaxy A2744_YD4 were made possible because this galaxy lies behind a massive galaxy cluster called Abell 2744. Because of a phenomenon called gravitational lensing, the cluster acted like a giant cosmic "telescope" to magnify the more distant A2744_YD4 by about 1.8 times, allowing the team to peer far back into the early Universe.

The ALMA observations also detected the glowing emission of ionised oxygen from A2744_YD4. This is the most distant, and hence earliest, detection of oxygen in the Universe, surpassing another ALMA result from 2016.

The detection of dust in the early Universe provides new information on when the first supernovae exploded and hence the time when the first hot stars bathed the Universe in light. Determining the timing of this "cosmic dawn" is one of the holy grails of modern astronomy, and it can be indirectly probed through the study of early interstellar dust.

The team estimates that A2744_YD4 contained an amount of dust equivalent to 6 million times the mass of our Sun, while the galaxy's total stellar mass -- the mass of all its stars -- was 2 billion times the mass of our Sun. The team also measured the rate of star formation in A2744_YD4 and found that stars are forming at a rate of 20 solar masses per year -- compared to just one solar mass per year in the Milky Way.

"This rate is not unusual for such a distant galaxy, but it does shed light on how quickly the dust in A2744_YD4 formed," explains Richard Ellis (ESO and University College London), a co-author of the study. "Remarkably, the required time is only about 200 million years -- so we are witnessing this galaxy shortly after its formation."

This means that significant star formation began approximately 200 million years before the epoch at which the galaxy is being observed. This provides a great opportunity for ALMA to help study the era when the first stars and galaxies "switched on" -- the earliest epoch yet probed. Our Sun, our planet and our existence are the products -- 13 billion years later -- of this first generation of stars. By studying their formation, lives and deaths, we are exploring our origins.

"With ALMA, the prospects for performing deeper and more extensive observations of similar galaxies at these early times are very promising," says Ellis.

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Silk Road evolved as 'grass-routes' movement

An aggregate "flow accumulation" model finds that nearly 75 percent of ancient Silk Road sites in the Inner Asian highlands fall along pathways (shown in red) that ancient Central Asian nomads likely used to move herds to prime summer pastures.
Nearly 5,000 years ago, long before the vast east-west trade routes of the Great Silk Road were traversed by Marco Polo, the foundations for these trans-Asian interaction networks were being carved by nomads moving herds to lush mountain pastures, suggests new research from Washington University in St. Louis.

"Our model shows that long-term strategies of mobility by highland nomadic herders structured enduring routes for seasonal migrations to summer pastures, which correspond significantly with the evolving geography of 'Silk Road' interaction across Asia's mountains," said Michael Frachetti, lead author of the study and an associate professor of anthropology in Arts & Sciences at Washington University.

The study, forthcoming in the journal Nature, combines satellite analysis, human geography, archaeology and Geographic Information Systems (GIS) to show that 75 percent of ancient Silk Road sites across highland Inner Asia fall along the paths its model simulates as optimal for moving herds to and from prime mountain meadows.

The model's innovative approach of tracing pasture-driven pathways suggests a number of alternate routes to many known Silk Road sites. It also provides a high-resolution mapping of other possibly important Silk Road routes that are previously unidentified and little researched, including an unexplored corridor into the Tibetan Plateau to the south of Dunhuang, China.

For over a century, the Silk Road -- a term coined in 1877 by German explorer Baron von Richthofen -- has intrigued modern historians and archaeologists who wish to understand the emergence of what many consider the world's most complex ancient overland trade system.

"The locations of ancient cities, towns, shrines and caravan stops have long illustrated key points of interaction along this vast network, but defining its many routes has been far more elusive," Frachetti said. "As a result, there is little known of the detailed pathways used for millennia by merchants, monks and pilgrims to navigate and interact across the highlands of Inner Asia."

Scholars have previously traced Silk Road trade corridors by modeling the shortest "least-cost" paths between major settlements and trade hubs. This connect-the-dots approach makes sense in lowland areas where direct routes across arid plains and open deserts correlate with ease of travel between trade centers. But it's not the way highland pastoralists traditionally move in rugged mountain regions, Frachetti argues.

"The routes of Silk Road interaction were never static, and certainly not in the mountains," Frachetti said. "Caravans traversing Asia were oriented by diverse factors, yet in the mountains their routes likely grew out of historically ingrained pathways of nomads, who were knowledgeable and strategic in mountain mobility."

Though Inner Asia's massive mountains separated oasis societies living in hot, arid lowlands, the region's mountain nomads were united by a shared ecological challenge: hot summers that left lowland pastures parched and barren. In response, mobile pastoralists evolved a similar strategy for success across the entire mountain corridor: escaping the grass-withering summer heat by driving flocks to higher elevations, Frachetti contends.

"Archaeology documents the development of mountain-herding economies in highland Asia as early as 3000 B.C., and we argue that centuries of ecologically strategic mobility on the part of these herders etched the foundational routes and geography of ancient trans-Asian trade networks," Frachetti said.

To test this theory, Frachetti and colleagues designed a model that simulates highland herding mobility as "flows" directed by seasonally available meadows. Although the model is generated without using Silk Road sites in its calculations, the pathways it projects show remarkable geographic overlap with known Silk Road locations compiled independently by Tim Williams, a leading Silk Road scholar at the Institute of Archaeology, University College London.

"The development of the Silk Roads through lowland deserts, fertile piedmonts and oases was influenced by many factors. However, the overlay of pasture-driven routes and known Silk Road sites indicate that the highland Silk Roads networks (750 m to 4,000 m) emerged in relation to long-established seasonal mobility patterns used by nomadic herders in the mountains of Inner Asia" said Williams, a co-author of this study. Williams also is author of the International Council on Monuments and Sites (ICOMOS) thematic study of the Silk Roads, which underpinned the UNESCO World Heritage serial transnational nominations.

Frachetti, who directs the Spatial Analysis, Interpretation, and Exploration (SAIE) laboratory at Washington University, has studied nomadic herding cultures and their ancient trade networks around the world. He has led excavations at sites in Uzbekistan, Kazakhstan and other Central Asian countries.

His field work documents that these societies had inter-continental connections spanning thousands of years, a phenomenon he traces to the antiquity of cross-valley pathways that, once engrained, formed the grassroots network that became the Silk Road.

Proving that theory is challenging because the Silk Road's central corridor runs through some of Inner Asia's most remote mountain ranges: the Hindu Kush in Northern Afghanistan; the Pamir in Tajikistan; the Dzhungar in Kazakhstan; the Tian Shan in Kyrgyzstan, Kazakhstan and Xinjiang (China); and the Altai Mountains in Kazakhstan, Russia and Mongolia.

His approach relies on the creative application of GIS and Remote Sensing tools normally used to simulate the flow of streams, rivers and other drainage through watersheds. In hydrological applications, "flow accumulation" relies on the known properties of water being pulled to lower elevations by gravity, generating calculations that show how runoff feeds into a network of ever-larger streams and rivers.

Frachetti swaps gravity for grass and uses the flow accumulation algorithm to calculate how the quality of lush pasture might channel flows of seasonally nomadic herders across a massive, 4,000-kilometer-wide cross-section of Asia's mountainous corridor.

The study area, which spans portions of Iran, India, Russia, Mongolia and China, was divided into a grid of one-kilometer cells, each of which received a numerical rating for grass productivity based on the reflectance of vegetation detected in multi-spectral satellite imagery. GIS software was used to calculate paths highland herders likely followed as pursuit of best-available grazing pulled them toward lowland settlements. The most likely routes were defined as those with the greatest cumulative flow over top pastures.

As Frachetti has found in earlier research, nomads do not wander aimlessly. Pastoralist movement through the mountains is rooted in local knowledge of the landscape and is guided by ecological factors, like the seasonal productivity of grassy meadows. Most confine their migrations to a small regular orbit that is closely repeated from year to year.

His flow model accommodates variation through time in the scale and distribution of prime highland grasslands, but suggests that the broad geography of mountain pasture has not changed drastically over the past several thousand years. Routes oriented for the best grazing would be well known to nomads making similar seasonal migrations over many generations.

Varying the simulated mobility model over 500 iterations (the rough equivalent of 20 generations), well-defined, grass-driven mobility patterns emerged. When the route-building process is shown dynamically, small pasture-based paths appear as rivulets and streams that converge over zones of rich pasture to form rivers of nomadic mobility.

While the study provides broad support for Frachetti's theories about the early evolution of the Silk Road, it also provides a roadmap for future research aimed at uncovering ancient structures of social participation across the mountains of Central Asia.

It also offers lessons, he suggests, about the importance of participation and connectivity in overcoming the great challenges that continue to confront civilizations.

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The protective layer of prehistoric land plants

Mosses cover a tree. An international research team has discovered a pathway with which these tiny plants produce their outer protective layer.
An international research team has discovered a biochemical pathway that is responsible for the development of moss cuticles. These waxy coverings of epidermal cells are the outer layer of plants and protect them from water loss. The biologists discovered this mechanism that facilitated the evolutionary transition of plants from fresh water to land in the moss Physcomitrella patens. The team was led by Professor Ralf Reski from the University of Freiburg/Germany and Doctor Danièle Werck-Reichhart from the Centre National de la Recherche Scientifique (CNRS) Institute of Plant Molecular Biology (IBMP) in Strasbourg/France and published their results in the journal Nature Communications.

Plant cuticles came into being more than 450 million years ago when the first plants colonized the hitherto hostile land masses. Because the waxy cuticles protect against water loss, they enabled the spread of plants on land and the subsequent evolution of our complex ecosystems. The seed plants that evolved later use similar chemical reactions to form the biopolymers lignin, cutin and suberin. Especially lignification of cell walls contributes to wood production and helps trees to grow several meters in height. In contrast, mosses do not contain lignin and are tiny. It remained unknown which biochemical pathway contributes to the protective layer on moss cells.

The researchers now found that the enzyme CYP98 from the family of cytochromes P450 plays a crucial role: While it initiates the production of lignin in seed plants, it is responsible for the development of a phenol-enriched cuticle in Physcomitrella. When they switched off the gene that is responsible for the synthesis of this enzyme, moss developed without cuticles. As a result, these moss plants were not protected against the environment and, moreover, were not able to form complex tissues: the developing organs fused and their further development was halted. The researchers could compensate this genetic defect by feeding the plants with caffeic acid, which they identified as the main component of the moss phenolic metabolism. The biologists conclude that the moss cuticle predated the evolution of lignin, cutin and suberin and may therefore originate from the last common ancestor of mosses and seed plants -- the prehistoric plants which left the fresh water to dwell on rocks and thus laid the foundation for the development of all current ecosystems on the mainland.

"Our results reveal one of the earliest evolutionary innovations that helped the first plants to survive on land over 450 million years ago," explains Reski. "It furthers suggests new biotechnology strategies for engineering biopolymers in plants beyond the well-known lignin production of trees."

From Science Daily

Mar 7, 2017

Caffeine boosts enzyme that could protect against dementia

Indiana University scientists have identified 24 compounds that increase the brain's production of the enzyme NMNAT2, which helps prevent the formation of these tangles associated with neurodegenerative disorders such as Alzheimer's disease.
A study by Indiana University researchers has identified 24 compounds -- including caffeine -- with the potential to boost an enzyme in the brain shown to protect against dementia.

The protective effect of the enzyme, called NMNAT2, was discovered last year through research conducted at IU Bloomington. The new study appears today in the journal Scientific Reports.

"This work could help advance efforts to develop drugs that increase levels of this enzyme in the brain, creating a chemical 'blockade' against the debilitating effects of neurodegenerative disorders," said Hui-Chen Lu, who led the study. Lu is a Gill Professor in the Linda and Jack Gill Center for Biomolecular Science and the Department of Psychological and Brain Sciences, a part of the IU Bloomington College of Arts and Sciences.

Previously, Lu and colleagues found that NMNAT2 plays two roles in the brain: a protective function to guard neurons from stress and a "chaperone function" to combat misfolded proteins called tau, which accumulate in the brain as "plaques" due to aging. The study was the first to reveal the "chaperone function" in the enzyme.

Misfolded proteins have been linked to neurodegenerative disorders such as Alzheimer's, Parkinson's and Huntington's diseases, as well as amyotrophic lateral sclerosis, also known as ALS or Lou Gehrig's disease. Alzheimer's disease, the most common form of these disorders, affects over 5.4 million Americans, with numbers expected to rise as the population ages.

To identify substances with the potential to affect the production of the NMNAT2 enzyme in the brain, Lu's team screened over 1,280 compounds, including existing drugs, using a method developed in her lab. A total of 24 compounds were identified as having potential to increase the production of NMNAT2 in the brain.

One of the substances shown to increase production of the enzyme was caffeine, which also has been shown to improve memory function in mice genetically modified to produce high levels of misfolded tau proteins.

Lu's earlier research found that mice altered to produce misfolded tau also produced lower levels of NMNAT2.

To confirm the effect of caffeine, IU researchers administered caffeine to mice modified to produce lower levels of NMNAT2. As a result, the mice began to produce the same levels of the enzyme as normal mice.

Another compound found to strongly boost NMNAT2 production in the brain was rolipram, an "orphaned drug" whose development as an antidepressant was discontinued in the mid-1990s. The compound remains of interest to brain researchers due to several other studies also showing evidence it could reduce the impact of tangled proteins in the brain.

Other compounds shown by the study to increase the production of NMNAT2 in the brain -- although not as strongly as caffeine or rolipram -- were ziprasidone, cantharidin, wortmannin and retinoic acid. The effect of retinoic acid could be significant since the compound derives from vitamin A, Lu said.

An additional 13 compounds were identified as having potential to lower the production of NMNAT2. Lu said these compounds are also important because understanding their role in the body could lead to new insights into how they may contribute to dementia.

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Survival instinct, not family bonds, weave massive spider colonies together

The spiders studied for this research build webs that require a lot of silk, making the rainy conditions of the lowland tropical rainforest too adverse for them to live alone.
Spiders will live in groups if environmental conditions make it too difficult for single mothers to go it alone, new research shows.

It is rare for spiders to live in groups. The arachnids studied for this research build webs that require a lot of silk, making the rainy conditions of the lowland tropical rainforest too adverse for them to live alone. The findings dispute a long-held belief that social groups form merely so individuals can help their kin. Instead it suggests difficult environmental conditions may be the reason why some species live in cooperative social groups and others don't.

"In all species, family members are closely related, but only in some do they band together to raise each others' offspring," said Leticia Avilés, a professor of zoology at UBC and senior author of the study. "By living in groups, the spiders can occupy spaces that they wouldn't otherwise be able to, thus helping us understand why animals evolve to be social species."

Avilés pointed to other animals to support this theory including penguins who are only able to survive extreme cold and winter storms by huddling together. She said this theory could also help explain why single-celled organisms merged together to form more complicated multicellular organisms in our evolutionary history.

For this research, Avilés and graduate student Catherine Hoffman spent time in Ecuador to study Anelosimus spiders and the habitats in which they occur. At higher elevations, where conditions are mild, Anelosimus tend to live in small colonies containing a single family, whereas lower down in the rainforest, where rains are strong and predation high, they live in colonies of hundreds to thousands.

The researchers took spiders living in single-family groups from the higher elevation and transplanted them to the rainforest below to measure how predators and rainfall affected how the spiders lived. They protected some groups from ant predators and others from heavy rainfall that damages their webs. They found that it was these environmental conditions that forced spiders to form larger colonies to help one another.

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Fault system off San Diego, Orange, Los Angeles counties could produce magnitude 7.3 earthquake

In 2013, Scripps research vessel New Horizon towed a hydrophone array to map the bathymetry of the Newport-Inglewood/Rose Canyon fault zone.
A fault system that runs from San Diego to Los Angeles is capable of producing up to magnitude 7.3 earthquakes if the offshore segments rupture and a 7.4 if the southern onshore segment also ruptures, according to an analysis led by Scripps Institution of Oceanography at the University of California San Diego.

The Newport-Inglewood and Rose Canyon faults had been considered separate systems but the study shows that they are actually one continuous fault system running from San Diego Bay to Seal Beach in Orange County, then on land through the Los Angeles basin.

"This system is mostly offshore but never more than four miles from the San Diego, Orange County, and Los Angeles County coast," said study lead author Valerie Sahakian, who performed the work during her doctorate at Scripps and is now a postdoctoral fellow with the U.S. Geological Survey. "Even if you have a high 5- or low 6-magnitude earthquake, it can still have a major impact on those regions which are some of the most densely populated in California."

The study, "Seismic constraints on the architecture of the Newport-Inglewood/Rose Canyon fault: Implications for the length and magnitude of future earthquake ruptures," appears in the American Geophysical Union's Journal of Geophysical Research.

The researchers processed data from previous seismic surveys and supplemented it with high-resolution bathymetric data gathered offshore by Scripps researchers between 2006 and 2009 and seismic surveys conducted aboard former Scripps research vessels New Horizon and Melville in 2013. The disparate data have different resolution scales and depth of penetration providing a "nested survey" of the region. This nested approach allowed the scientists to define the fault architecture at an unprecedented scale and thus to create magnitude estimates with more certainty.

They identified four segments of the strike-slip fault that are broken up by what geoscientists call stepovers, points where the fault is horizontally offset. Scientists generally consider stepovers wider than three kilometers more likely to inhibit ruptures along entire faults and instead contain them to individual segments -- creating smaller earthquakes. Because the stepovers in the Newport-Inglewood/Rose Canyon (NIRC) fault are two kilometers wide or less, the Scripps-led team considers a rupture of all the offshore segments is possible, said study co-author Scripps geologist and geophysicist Neal Driscoll.

The team used two estimation methods to derive the maximum potential a rupture of the entire fault, including one onshore and offshore portions. Both methods yielded estimates between magnitude 6.7 and magnitude 7.3 to 7.4.

The fault system most famously hosted a 6.4-magnitude quake in Long Beach, Calif. that killed 115 people in 1933. Researchers have found evidence of earlier earthquakes of indeterminate size on onshore portions of the fault, finding that at the northern end of the fault system, there have been between three and five ruptures in the last 11,000 years. At the southern end, there is evidence of a quake that took place roughly 400 years ago and little significant activity for 5,000 years before that.

Driscoll has recently collected long sediment cores along the offshore portion of the fault to date previous ruptures along the offshore segments, but the work was not part of this study.

In addition to Sahakian and Driscoll, study authors include Jayne Bormann, Graham Kent, and Steve Wesnousky of the Nevada Seismological Laboratory at the University of Nevada, Reno, and Alistair Harding of Scripps. Southern California Edison funded the research at the direction of the California Energy Commission and the California Public Utilities Commission.

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Species appears to evolve quickly enough to endure city temperatures

Acorn ants evolve quickly to adjust to living in heat-trapping cities. The capability that may prove essential to enduring other sources of rising temperatures, such as climate change.
The speed at which a tiny ant evolves to cope to its warming city environment suggests that some species may evolve quickly enough to survive, or even thrive, in the warmer temperatures found within cities, according to a new study by researchers at Case Western Reserve University.

Evolution is often thought of as a process that takes millennia, but urban acorn ants collected in Cleveland have taken no more than 100 years to adjust to their heat-trapping home of asphalt and concrete steeped with waste heat from cars and buildings -- although their tolerance to cold was reduced.

The researchers' findings are published online in the Biological Journal of the Linnean Society.

"Ants are an indicator species, and by comparing the physiologies of urban versus rural ants, we can get an idea of whether ants and other cold-blooded animals will be able to cope with the temperature changes associated with urbanization and other sources of warming like global climate change," said Sarah Diamond, assistant professor of biology at Case Western Reserve and the study's lead author.

Diamond worked with Ryan Martin, assistant professor of biology, research associates Lacy Chick and Stephanie Strickler, and PhD student Abe Perez.

Cities tend to be a couple of degrees warmer than surrounding rural areas. To determine whether animals evolve or simply adjust to added warmth, the research team collected and compared acorn ants from the city and nearby rural land.

The acorn ant (Temnothorax curvispinosus) is widespread and important for decomposing organic material in urban and rural environments across the United States. This species of ant is smaller than a cookie crumb; an entire colony of 250 can fit in a single acorn.

The researchers collected colonies from within the city of Cleveland and as far as 28 miles east from the Holden Arboretum in suburban Kirtland, Ohio, to study in Diamond's lab.

To isolate evolutionary change from short-term acclimation, groups of rural and city ants were raised in warmer city temperatures for about 10 weeks. Other groups from both locations were raised in cooler rural temperatures for 10 weeks.

Tests of thermal tolerance showed all the ants acclimated.

"They're very plastic," Martin said. "But ants collected from city habitats retained their higher heat tolerance and loss of cold tolerance compared to rural ants, regardless of whether they were born and reared under warm or cool temperatures."

Martin and Diamond believe the Cleveland ants evolved as the city became and remained highly urban during the last 100 years. Because egg-laying queen ants live from five to 15 years, the evolution to heat tolerance likely took no more than 20 generations, the researchers estimated.

With temperatures predicted to rise at least a couple of degrees Celsius over the next century, "Global data suggests that the acclimation response won't be enough to respond to climate change, but some species, like the acorn ants, may evolve quickly enough," Diamond said.

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Mar 6, 2017

Study shows how skates, rays and sharks sense electrical fields

This is an Ampullary bundle with afferent nerve.
Sharks, rays and skates can hunt for prey hidden in the sandy sea floor by "listening" for faint traces of bioelectricity -- they can literally sense their prey's heart beating. The basic anatomy of the electro-sensory organs that accomplish this feat has been known for decades, but the biological mechanisms -- how electrosensory cells pick up faint electrical signs of life -- has remained a puzzle.

Now, in a new study published online in Nature, researchers at UC San Francisco have cracked the mystery of the electrosensory organ of Leucoraja erinacea, commonly called the little skate, in a series of experiments that traced the mechanisms of electrosensation all the way from genes to cell physiology to behavior.

"Skates and sharks have some of the most sensitive electroreceptors in the animal world," said David Julius, PhD, professor and chair of physiology at UCSF and senior author of the new study. "Understanding how this works is like understanding how proteins in the eye sense light -- it gives us insight into a whole new sensory world."

In their study, the researchers first isolated electrosensory cells from skate ampullary organs, which mediate electrosensation, and then performed sensitive recordings that revealed two ionic currents -- a voltage-sensitive calcium current that admits calcium ions into the cell in response to electrical disturbances and a calcium-sensitive potassium current alters the normal electrical properties of the cell. These currents interact with one another to set up an electrical oscillation in the cells' membranes that is exquisitely sensitive to outside electrical disturbances. This oscillation acts almost like an amplifier to enable the skate to detect the tiny electrical perturbations produced by the electrical field of a prey organism.

Gene expression experiments -- which required researchers to functionally annotate the skate genome -- confirmed the identity of two particular subtypes of calcium and potassium channels (called the CaV1.3 and BK channels respectively) with unique characteristics that enable skates' electrosensory perception. In one experiment, the researchers added targeted mutations to similar ion channel genes from the rat genome to make them more like the skate channels -- experiments in lab dishes showed that these changes conferred electrical properties on the rat channels that made them work like those from skate electrosensory cells.

Finally, the researchers demonstrated the behavioral importance of these channels for skate electrosensation: they placed live skates in tanks with an electrical source hidden under a layer of sand and showed that while normal skates spent much of their time orienting towards and investigating the quadrant of the tank with the hidden electrical signal, skates with these key ion channels blocked by drugs appeared unaware of the simulated meal just inches away.

The findings not only reveal new insights about how skates and sharks find their dinners, but could reveal new information about our own biology, the researchers say. Remarkably, the skate's electrosensory system is evolutionarily related to the mammalian auditory system, and there are many similarities between the skate's electrosensory organs and the "hair cells" of the inner ear responsible for sensitive hearing in mammals.

"Versions of the same ion channels with subtly different electrical properties are similarly important in our ears," said Nicholas Bellono, PhD, a postdoctoral researcher in the Julius lab and co-lead author of the new study. "So understanding exactly how small differences in these channels affect electrical function could be important for better understanding the auditory system."

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Cold extermination: One of greatest mass extinctions was due to an ice age and not to Earth's warming

Permian-Triassic boundary in shallow marine sediments, characterised by a significant sedimentation gap between the black shales of Permian and dolomites of Triassic age. This gap documents a globally-recognised regression phase, probably linked to a period of a cold climate and glaciation.
Earth has known several mass extinctions over the course of its history. One of the most important happened at the Permian-Triassic boundary 250 million years ago. Over 95% of marine species disappeared and, up until now, scientists have linked this extinction to a significant rise in Earth temperatures. But researchers from the University of Geneva (UNIGE), Switzerland, working alongside the University of Zurich, discovered that this extinction took place during a short ice age which preceded the global climate warming. It's the first time that the various stages of a mass extinction have been accurately understood and that scientists have been able to assess the major role played by volcanic explosions in these climate processes. This research, which can be read in Scientific Reports, completely calls into question the scientific theories regarding these phenomena, founded on the increase of CO2 in the atmosphere, and paves the way for a new vision of Earth's climate history.

Teams of researchers led by Professor Urs Schaltegger from the Department of Earth and Environmental Sciences at the Faculty of Science of the UNIGE and by Hugo Bucher, from the University of Zürich, have been working on absolute dating for many years. They work on determining the age of minerals in volcanic ash, which establishes a precise and detailed chronology of Earth's climate evolution. They became interested in the Permian-Triassic boundary, 250 million years ago, during which one of the greatest mass extinctions ever took place, responsible for the loss of 95% of marine species. How did this happen? for how long marine biodiversity stayed at very low levels?

A technique founded on the radioactive decay of uranium.

Researchers worked on sediment layers in the Nanpanjiang basin in southern China. They have the particularity of being extremely well preserved, which allowed for an accurate study of the biodiversity and the climate history of the Permian and the Triassic. "We made several cross-sections of hundreds of metres of basin sediments and we determined the exact positions of ash beds contained in these marine sediments," explained Björn Baresel, first author of the study. They then applied a precise dating technique based on natural radioactive decay of uranium, as Urs Schaltegger added: "In the sedimentary cross-sections, we found layers of volcanic ash containing the mineral zircon which incorporates uranium. It has the specificity of decaying into lead over time at a well-known speed. This is why, by measuring the concentrations of uranium and lead, it was possible for us to date a sediment layer to an accuracy of 35,000 years, which is already fairly precise for periods over 250 million years." Ice is responsible for mass extinction

By dating the various sediment layers, researchers realised that the mass extinction of the Permian-Triassic boundary is represented by a gap in sedimentation, which corresponds to a period when the sea-water level decreased. The only explanation to this phenomenon is that there was ice, which stored water, and that this ice age which lasted 80,000 years was sufficient to eliminate much of marine life. Scientists from the UNIGE explain the global temperature drop by a stratospheric injection of large amounts of sulphur dioxide reducing the intensity of solar radiation reaching the surface of Earth. "We therefore have proof that the species disappeared during an ice age caused by the activity of the first volcanism in the Siberian Traps," added Urs Schaltegger. This ice age was followed by the formation of limestone deposits through bacteria, marking the return of life on Earth at more moderate temperatures. The period of intense climate warming, related to the emplacement of large amounts of basalt of the Siberian Traps and which we previously thought was responsible for the extinction of marine species, in fact happened 500,000 years after the Permian-Triassic boundary.

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