Nov 19, 2016
The feces were originally found in a latrine box in 1937 when bishop Jens Bircherod's manor was excavated in the northern city of Aalborg.
But they were only recently analysed as part of a research project on diaspora communities in Danish cities between the early 15th century and the late 17th century.
"Now we have a specific lump of feces that we can match to a person we actually know, and through that we can study his diet," the archaeologist heading the project, Jette Linaa from the Moesgaard Museum outside the Danish city of Aarhus, told AFP.
While most other latrines from the late 17th century were used by many different people, this one was only used by Bircherod and his wife.
The presence of buckwheat, a local specialty on the Danish island of Funen where the bishop grew up, was further evidence that the sample came from him.
Researchers were also able to compare the findings with the Bishop's diaries, in which he detailed some of the "opulent" dinners that he had.
While most Danes at the time had to settle for regional staples like pork, rye bread and cabbage, the bishop -- along with other wealthy residents of Aalborg — appears to have had a penchant for berries and nuts.
A peppercorn that was found would have had to travel all the way from India, while cloudberries eaten by Bircherod could have come from Norway.
"The exotic products were traded by some very specialized merchants in the city, and Aalborg was special because there was a class of very prosperous merchants who were all either migrants from Germany or from the Netherlands," Linaa said.
From Discovery News
And scientists recently discovered a spider that uses a unique masquerade to hide in plain sight. It is the only known spider to have a body that bears an uncanny resemblance to a dangling, partly dried-up leaf.
The find was reported in a new study, though the spider is yet to be described and assigned a species name.
The newfound costumed arachnid is in the Poltys genus in the orb spider family, which contains more than 3,000 species and one spider celebrity from children's fiction — a Araneus cavaticus was the barn spider Charlotte from the classic story "Charlotte's Web" (Harper and Brothers, 1952).
Masquerading is far more common in insects than in arachnids. In fact, many types of insects have bodies that mimic plants. For example, the Phasmatodea order contains hundreds of species of so-called stick insects, which look like bare branches or leaves. And brightly colored orchid mantises have petal-shaped legs to complete their disguises as harmless flowers, tricking other insects into flying close enough for the mantises to snatch them out of the air.
But about 100 spider species also sport physical features that make them appear inanimate and unappetizing, like a jumble of twigs, plant debris or a messy glob of bird poo.
This is the first known spider species to be leaf-shaped. And its discovery was accidental, according to the study's lead author, Matjaz Kuntner, a principal investigator with the Evolutionary Zoology Lab at the Biological Institute Jovan Hadzi, Scientific Research Centre of the Slovenian Academy of Sciences and Arts.
The scientists spied and photographed the unusual arachnid in 2011, while looking for other types of spiders in Yunnan, China. They found the individual — a female — on a twig, surrounded by dead leaves and with no web nearby. The researchers noted that her back looked like a living, green leaf, while the underside of her body was brown, mimicking a dead leaf, and a hairy, stalk-like structure protruded from her abdomen.
|The greenish-yellow underside of the spider resembles a fresh leaf, and the hairy, stalk-like structure curving from its abdomen makes it look even more like a plant.|
After searching for two weeks, Kuntner and colleagues were able to find only one more leaf-shaped spider — a juvenile male, crouching on a web. Next, they turned to museums to see if they could turn up more specimens, Kuntner said.
Read more at Discovery News
Nov 18, 2016
|Virus and bacteria (stock image). This new research provides new insight into how groups of bacteria collectively defend against viral threats.|
The findings by a team led by Associate Professor Peter Fineran of the Department of Microbiology and Immunology appear in the international journal Molecular Cell.
Associate Professor Fineran says that in the same way that humans are susceptible to viruses like influenza and measles, bacteria also need to defend themselves against viruses.
"As humans, we have evolved sophisticated immune systems that enable our bodies to fight the viral infections that render us ill. Amazingly, bacteria -- although single celled organisms -- often possess similar adaptive immunity called CRISPR-Cas systems. But the way that these CRISPR-Cas systems function is very much different to our own immune systems," he says.
His team's research provides new insight into how groups of bacteria collectively defend against viral threats.
"People have long understood the advantages of living in communities and bacteria are no different, often residing in close quarters to share resources. However, there are also potential drawbacks to community life as high-density bacterial populations are more vulnerable to the spread of viruses -- just like people in a crowded bus or a daycare centre," he says.
The breakthrough came when the researchers discovered that the ability of bacteria to gauge the number of cells in their communities enabled the bacteria to boost the power of their CRISPR-Cas immune systems to prevent viral outbreaks.
Associate Professor Fineran says the bacteria sense the population density by "talking" to each other using a form of chemical communication known as quorum sensing.
"The higher the population density, the stronger the communication between cells becomes, which results in greater coordination of immune defenses," he says.
Adrian Patterson, a PhD student and first author on the paper, says the study shows that bacterial cells preemptively elevate their immunity when they are most at risk of a virus spreading through the population.
"They both increase their ability to generate new immune memories and strengthen existing immunity by up to 500-fold," Mr Patterson says.
The role of CRISPR-Cas in providing bacteria with viral immunity was only discovered in the past decade.
The systems create genetic memories of specific past viral infections by taking little snippets of the viruses' DNA and storing them in memory banks to aid in recognising and destroying future infections.
One of the least understood aspects of the CRISPR-Cas field is how bacteria control the activity of these systems. Too much activity can result in an autoimmune-like disease, killing the host cell, but too little activity might allow viruses to wipe out entire bacterial communities. The team's research shows that by openly communicating with each other, bacteria strike the right balance between these two outcomes.
Read more at Science Daily
|This photograph shows a 5,310-year-old corn cob.|
"Around 9,000 years ago in modern-day Mexico, people started collecting and consuming teosinte, a wild grass," says Nathan Wales of the Natural History Museum of Denmark. "Over the course of several thousand years, human-driven selection caused major physical changes, turning the unproductive plant into modern maize, commonly known as corn. Maize as we know it looks so different from its wild ancestor that a couple of decades ago scientists had not reached a consensus regarding the true ancestor of maize."
To better understand the domestication history of the world's most produced crop, Wales and his colleagues, including Jazmín Ramos-Madrigal, sequenced the genome of a 5,310-year-old maize cob from central Mexico. The cob, known as Tehuacan162, was excavated from a cave in the Tehuacan Valley in the 1960s, during a major archaeological expedition lead by Richard MacNeish.
Fortunately, the Robert S. Peabody Museum in Andover, MA, took excellent care of the ancient maize specimen -- one of the five oldest known in the world -- for decades. Wales explains that this particular cob and the DNA within it had been unusually well preserved.
"Archaeological specimens frequently have high levels of bacterial DNA due to decomposition and soil contaminants," he says. "However, during genetic testing of ancient cobs, we were astonished to find that 70 percent of the DNA from the Tehuacan162 cob was from the plant!" Most other ancient samples contain less than 10 percent plant DNA.
Tehuacan162 didn't have hard seed coats like its wild ancestor would have. But, the ancient cob is less than a tenth of the size of modern cobs, at less than two centimeters long. In addition, the ancient cob produced only eight rows of kernels, about half that of modern maize. That led the researchers to suspect that its genes would offer clues on the early stages of maize domestication.
To make the most of the small sample, Wales and Ramos-Madrigal used cutting-edge paleogenomic techniques. They extracted DNA with a method designed to recover ultra-short DNA, taking special care to avoid losing any genetic material. As a result, the researchers were able to prepare sufficient DNA for sequencing while still preserving enough of the sample to determine the cob's precise age via radiocarbon dating.
The new findings offer an informative snapshot in the 10,000-year evolutionary history of maize and its domestication, the researchers say. In addition to elucidating how maize provided a dietary foundation for ancient civilizations like the Maya, such studies can also aid in understanding and improving commercially important lines of modern maize, the researchers say.
Read more at Science Daily
Scientists working at the Wallula Basalt Pilot Project in Washington State turned liquefied carbon dioxide into solid rock by injecting the gas into basalt formations. Over a span of about two years, the carbon dioxide solidified into a mineral called ankerite, according to the study conducted by Pacific Northwest National Laboratory researchers. The research was published in the journal Environmental Science and Technology.
"This study further supports the idea that one of the major rock types on the planet — basalts — can be used to store carbon dioxide permanently and safely," said study lead author Pete McGrail, a carbon dioxide and climate change researcher at PNNL.
Carbon capture and storage may be critical to helping prevent global warming from exceeding 2°C (3.6°F), either by capturing emissions from their source or by directly removing carbon dioxide from the atmosphere, according to the Intergovernmental Panel on Climate Change.
But scientists worry that storing captured carbon underground as a liquid or a gas may not be safe because stored carbon dioxide could explosively leak into the atmosphere through fissures in the earth or be exposed to terrorism risk, creating a climate catastrophe.
To solve that problem, researchers have been studying ways to store carbon dioxide underground as a solid, especially in basalt formations.
Basalt is a volcanic rock that makes up roughly 70 percent of the earth's surface. When it is exposed to carbon dioxide and water, a chemical reaction occurs, converting the gas to a chalk-like solid material. Scientists previously thought the chemical reaction would take thousands of years to occur, but new research shows it can happen within a few years.
"Basalt storage is unique in the geologic sequestration of carbon dioxide because the principal trapping mechanism is a chemical reaction that locks the carbon dioxide away as a carbonate mineral that can never leak or return to the atmosphere," McGrail said.
Earlier this year, researchers at the CarbFix project in Iceland were able to pump a geothermal power plant's carbon dioxide-rich volcanic gases into deep underground but recently formed basalt formations and chemically solidify them in about two years.
The Wallula project is the first to show carbon dioxide could be solidified in the ancient basalts that are more common globally, said Paul Olsen, an earth and environmental sciences professor at the Lamont-Doherty Earth Observatory at Columbia University who is unaffiliated with either study.
"The recent highly successful CarbFix project in Iceland showed that the conversion of carbon dioxide into limestone could be very fast, but that project used the much more recent lava flows of Iceland and it was not clear the process would work on ancient lava flows such as those that are widespread in many places on land near major cities and their associated power plants," Olsen said. "It was also the first major test using liquefied carbon dioxide that is relatively easy to transport."
The Wallula project's success shows that commercial-scale carbon sequestration from electric power plants is possible, albeit more research needs to be done to show how the process could be scaled for use commercially around the world.
"It is not a total solution to the problem by any measure," Olsen said. "It is, however, one part of a solution, especially as a bridge until fossil fuel-burning power plants can be replaced by renewable sources of energy or even nuclear."
McGrail said there is no risk of the solidified carbon dioxide to dissolve in water and escape back into the atmosphere.
Read more at Discovery News
The finding could shed light on how impacts can reshape the faces of planets and how such collisions can generate new habitats for life, the researchers said.
Asteroids and comets occasionally pelt Earth's surface. Still, for the most part, changes to the planet's surface result largely from erosion due to rain and wind, "as well as plate tectonics, which generates mountains and ocean trenches," said study co-author Sean Gulick, a marine geophysicist at the University of Texas at Austin.
In contrast, on the solar system's other rocky planets, erosion and plate tectonics typically have little, if any, influence on the planetary surfaces. "The key driver of surface changes on those planets is constantly getting hit by stuff from space," Gulick told Live Science.
The researchers in the new study looked at Earth features to learn more about impact effects found on other solar system objects. Major craters sometimes possess rings of rocky hills in their centers. Most of these "peak rings" exist on extraterrestrial rocky bodies such as the moon or Venus, making it difficult to analyze these structures in detail and pin down their origins.
So to learn more about peak rings, scientists investigated a gargantuan crater on Earth that measures more than 110 miles (180 kilometers) across, located near the town of Chicxulub (CHEEK-sheh-loob) in Mexico's Yucatán Peninsula. This crater likely resulted from the epic crash of an object about 6 miles (10 km) wide, and the resulting impact is thought to have ended the age of dinosaurs about 65 million years ago.
The researchers focused on the Chicxulub crater because it has the only intact peak ring on Earth. In contrast, larger craters on Earth, such as Sudbury in Canada or Vredefort in South Africa, "have [been] heavily eroded — neither one has peak rings anymore," Gulick said. "On the other hand, Chicxulub's peak ring is completely preserved."
The structures that the researchers wanted to examine were under about 60 feet (18 meters) of water in the Gulf of Mexico. To collect samples from these structures, the scientists traveled to the site in the spring of 2016 in a "liftboat" that could lower three pillars into the seafloor and lift the boat off the water by about 50 feet (15 m). The liftboat then lowered drills into the seafloor and "drilled into the crater for two months, to as low as 1,335 meters [4,380 feet] below the seafloor," Gulick said. (Lifting the boat from the water helps it avoid waves that can rock the vessel and snap the drill pipe.)
In the peak ring samples, the scientists discovered granite that likely once was deeply buried for about 500 million years, Gulick said. "These deeply buried rocks rose up to the surface of the Earth within the first few minutes of the impact," Gulick said. "They showed evidence they experienced a high degree of shock from the impact."
After the impact, "the earth there would have temporarily behaved like a slow-moving fluid," Gulick said. "The stony asteroid would have opened up a hole probably almost the thickness of Earth's crust, almost 30 km [18 miles] deep, and on the order of 80 to 100 km [50 to 62 miles] wide."
And similar to how fluids behave, the earth would immediately flow to fill in the hole, meaning the sides of the crater would collapse inward, he added. [When Space Attacks: The 6 Craziest Impact Craters]
"At the same time, the center of this hole starts reaching upwards, like when you throw a rock in a pond and you get a water droplet rising in the middle," Gulick said. "The center would have risen up from the surface of the Earth as much as 15 km [9 miles], and then become gravitationally unstable, collapsing downwards and outwards."
The end result of this dynamic process is a ring of mountains, or the peak ring, the researchers said.
The study's findings support one of the two main hypotheses that describe peak ring formation, the researchers said. One explanation suggested that peak rings originate closer to the surface: As an impact causes a peak to form in the middle of the crater, the uppermost part of this peak melts, causing the material to disperse into a ring of peaks. The other hypothesis suggested that peak rings formed because impacts dug deep into their targets.
"It turns out the models based on the deeper origins seemed to have gotten it right," Gulick said. "The model these findings support is based on what are known as hydrocode models, which are used for simulating nuclear bomb blasts. Those models simulate an asteroid impacting a target at close to about 20 km per second [44,740 mph], which can get the crust to flow."
Unexpectedly, the researchers noted that rocks from peak rings "got fundamentally altered by their journey upward during the impact," Gulick said. "They end up lower in density by a lot, with their porosity increasing from 1 to 2 percent to 10 percent."
Read more at Discovery News
Nov 17, 2016
|Split drill cores collected from the peak ring of Chicxulub crater. The left two cores consist of basement granite. The right two cores are impact melt rocks that were created by the heat associated with the impact.|
Around 65 million years ago a massive asteroid crashed into the Gulf of Mexico causing an impact so huge that the blast and subsequent knock-on effects wiped out around 75 per cent of all life on Earth, including most of the dinosaurs. This is known as the Chicxulub impact.
In April and May 2016, an international team of scientists undertook an offshore expedition and drilled into part of the Chicxulub impact crater. Their mission was to retrieve samples from the rocky inner ridges of the crater -- known as the 'peak ring' -- drilling 506 to 1335 metres below the modern day sea floor to understand more about the ancient cataclysmic event.
Now, the researchers have carried out the first analysis of the core samples. They found that the impact millions of years ago deformed the peak ring rocks in such a way that it made them more porous, and less dense, than any models had previously predicted.
Porous rocks provide niches for simple organisms to take hold, and there would also be nutrients available in the pores, from circulating water that would have been heated inside the Earth's crust. Early Earth was constantly bombarded by asteroids, and the team have inferred that this bombardment must have also created other rocks with similar physical properties. This may partly explain how life took hold on Earth.
The study, which is published today in the journal Science, also confirmed a model for how peak rings were formed in the Chicxulub crater, and how peak rings may be formed in craters on other planetary bodies.
The team's new work has confirmed that the asteroid, which created the Chicxulub crater, hit the Earth's surface with such a force that it pushed rocks, which at that time were ten kilometres beneath the surface, farther downwards and then outwards. These rocks then moved inwards again towards the impact zone and then up to the surface, before collapsing downwards and outwards again to form the peak ring. In total they moved an approximate total distance of 30 kilometres in a matter of a few minutes.
Professor Joanna Morgan, lead author of the study from the Department of Earth Science and Engineering, said: "It is hard to believe that the same forces that destroyed the dinosaurs may have also played a part, much earlier on in Earth's history, in providing the first refuges for early life on the planet. We are hoping that further analyses of the core samples will provide more insights into how life can exist in these subterranean environments."
Read more at Science Daily
However, though all stars spin, astronomers have made a surprise discovery and realized that there's a star out there that's not only almost perfectly spherical, but it could be the most perfectly spherical object ever found in nature.
Kepler 11145123 is located around 5,000 light-years from Earth and, using four years of data from NASA's exoplanet-hunting Kepler space telescope, a team of astronomers led by Laurent Gizon, of the Max Planck Institute for Solar System Research and the University of Göttingen, were able to precisely measure the star's oscillations in brightness. And these oscillations revealed Kepler 11145123's secret.
All stars oscillate, much like a sphere of Jello would wobble when placed on a speaker playing Metallica. By measuring the Jello wobbles, we would be able to calculate the frequency of the sound waves passing through the substance and then, from these measurements, we'd be able to understand how dense the Jello is and even gauge its precise shape. Although stars don't wobble nearly as dramatically as this Jello example, waves ripple through our sun and these waves can be measured to help us understand what our star is physically made of. This field of study is called helioseismology; when studying other stars, it's called astroseismology.
So, by measuring the modes of oscillation (revealed by slight changes in brightness), Gizon's team was able to "see" that Kepler 11145123 supports purely sinusoidal modes of oscillation. By comparing the frequencies that are sensitive to the star's high latitudes and those that are sensitive to the low latitudes, they were able to precisely measure the "oblateness" of the star. And what they found was a surprise. The star is only 3 kilometers (1.9 miles) wider at its equator than the distance between its poles.
"This makes Kepler 11145123 the roundest natural object ever measured, even more round than the sun" said Gizon in a statement. Though the star is rotating three times slower than our sun, Kepler 11145123 is a lot more spherical than thought possible.
Read more at Discovery News
New research has confirmed that the point-by-point connections that make up the mesh-like white matter of your brain are truly unique to each individual person, and are perpetually shaped not only by genetics but also by experience.
"If we compare a brain structure to a complicated circuit, the white matter is the wiring of the circuit," Fang-Cheng (Frank) Yeh, lead author of the study appearing in PLOS Computational Biology, told Seeker. "Everyone's wiring is unique and can actually define who a person is — his or her personality, experience, education."
Before you start imagining brain scanners at ID checkpoints, keep in mind that because our brain fingerprints are constantly shaped by experience, it's unlikely the finding will lead to a new identification tool.
Instead, the hope is by scanning people's brain fingerprints, doctors and researchers will have a new way to diagnose and possibly treat mental illnesses such as depression and bipolar disorder.
It also offers unique insight into how shared experience can directly impact biology — particularly the brain's map of neural connections, otherwise known as our connectomes.
"There are a couple of things we can take away from this," coauthor and Carnegie Mellon University Assistant Professor of Psychology Timothy Verstynen told Seeker in an email. "First, it gives us another measure by which to see and measure neuroplasticity. Second, and more importantly, it alludes to the fact that individuals with similar experiences may start to show more similar structural connectomes."
To confirm everyone's wiring pattern is unique, Yeh, a neurosurgeon at the University of Pittsburgh, and colleagues from Carnegie Mellon University used diffusion MRI to precisely measure connections along all of the white matter pathways in the brain. Diffusion MRIs use the diffusion of water molecules in tissue to generate contrast in images.
After measuring more than 17,000 multiple local connections within the brains of 699 subjects, they were able to read the scans and then determine whether two connections came from the same person or not — with nearly 100 percent accuracy.
Even identical twins featured unique brain fingerprints since a person's white matter is shaped by outside factors as well as genetics. Twins only share 12 percent of the same structural patterns in their brain wiring, the team found.
"An interesting future study would look at the brain fingerprint of twins at a young age and then track how their brain fingerprints became different over time," said Yeh.
Life experience plays such a role in shaping your brain fingerprint, that your white matter's structural patterns change by an average of 13 percent every 100 days, the researchers found.
"We think that experience has a profound and powerful impact on the unique connectivity profile of the structural connections in your head," Verstynen told Seeker.
"What we want to do next is see if we can similarities in the local connectome across people. For example do people who grew up with the same life experiences have similar structural connections? Or do people who have similar cognitive abilities also have similar connectomes?" Verstynen posed. "If we can find this, then it suggests that maybe we can also find other common patterns."
Read more at Discovery News
A 10-meter (33-foot) tall pyramid was found within another 20-meter structure, which itself is enveloped by the 30-meter pyramid visible at the Mayan archeological complex known as Chichen Itza in Yucatan state.
The smallest pyramid was built between the years 550 and 800, engineers and anthropologists said.
The middle structure had already been discovered in the 1930s and dates back to the years 800-1,000, while the largest one was finished between 1050-1300.
The discovery suggests that the pyramid, known as "El Castillo" (The Castle), was built in three phases.
"It's like a Russian nesting doll. Under the large one we get another and another," Rene Chavez Seguro, the project's chief and a geophysics researcher at the National Autonomous University of Mexico, told a news conference.
Structures were built on top of each other for various reasons, including deterioration or the arrival of new leadership, said Denisse Argote, expert at the National Anthropology and History Institute.
The smallest pyramid was spotted using a non-invasive technique that consists in lighting the inside of the pyramid to see its interior without causing damage.
The discovery could shed light on the original Mayan culture before it was influenced by populations from central Mexico, Argote said.
Last year, archeologists discovered that the Kukulkan pyramid was built atop a cenote, or underground river, which are common in the region and are sacred to the Maya.
From Discovery News
The appliance consists of five teeth — three central incisors and two lateral canines aligned in an incorrect anatomical sequence. Belonging to different individuals, the teeth were linked together by a golden band.
To build the prosthesis, the root apex of each tooth was removed and a longitudinal cut was made along the roots.
"The teeth were then aligned and a subtle golden lamina was inserted into the fissure," Simona Minozzi, Valentina Giuffra, at the division of paleopathology of Pisa University, and colleagues wrote in the Clinical Implant Dentistry and Related Research journal.
"Micro-CT scan revealed the presence of two small golden pins inserted into each tooth crossing the root and fixing the teeth to the internal gold band," the researchers said.
The prosthesis was anchored to the individual's teeth through two S-shaped ends featuring two small holes. Strings were probably used to hold it in place.
Using a scanning electron microscope, the researchers found that the golden lamina is a metal alloy made of 73 percent of gold, 15.6 percent of silver and 11.4 percent of copper.
Appliances to hold loose teeth in place had been described by the innovative French surgeon Ambroise Paré (1510–1590) who served as royal surgeon for a number of French kings, and by Pierre Fauchard (1678–1761), who was widely considered the father of modern dentistry.
But until now, no direct evidence of such devices had been found.
"This is the first archaeological evidence of a dental prosthesis using gold band technology for the replacement of missing teeth," Minozzi told Discovery News.
|CT images of the prosthesis reveal the small pins placed into the root and blocking the teeth at the internal gold lamina.|
"The golden prosthesis is much more complex because the gold lamina ran inside the dental roots and the teeth were blocked with golden pins," Minozzi said.
The prosthesis was found in the monastery of S. Francesco at Lucca, during excavations funded by the Fondazione Cassa di Risparmio of Lucca. Two large stone tombs contained the remains of the Guinigis, a powerful family who governed the city from 1392 until 1429.
Over the years, skeletal remains of successive burials accumulated in the tombs, so it wasn't possible to provide an accurate dating for the device.
"Some pottery fragments and devotional medals found in the same stratigraphic layer were dated to the beginning of the 17th century," the researchers said.
The prosthesis was found among the mingled remains of about 100 individuals.
"We couldn't find the corresponding jaw, so we do not know who the appliance belonged to," Minozzi said.
Minozzi and colleagues speculate the individual might have lost the teeth because of decay, gum infection or even age.
Indeed, the examination of the 100 skeletons in the tomb revealed that half of them were over 40 at the time of death — an advanced age for the time — and many suffered from tooth diseases.
"Among the aristocratic Guinigis, the presence of cavities, periodontitis and missing teeth was more than double compared to the Tuscan rural population," Minozzi said.
Read more at Discovery News
Nov 16, 2016
|In this image of Pluto taken by NASA's New Horizons spacecraft, different colors represent different compositions of surface ices, revealing a surprisingly active body.|
Published in the Nov. 17 issue of Nature, these are the conclusions of research by James Keane, a doctoral student at the University of Arizona's Lunar and Planetary Laboratory, and his adviser, assistant professor Isamu Matsuyama. They propose evidence of frozen nitrogen pileup throwing the entire planet off kilter, much like a spinning top with a wad of gum stuck to it, in a process called true polar wander.
"There are two ways to change the spin of a planet," Keane said. "The first -- and the one we're all most familiar with -- is a change in the planet's obliquity, where the spin axis of the planet is reorienting with respect to the rest of the solar system. The second way is through true polar wander, where the spin axis remains fixed with respect to the rest of the solar system, but the planet reorients beneath it."
Planets like to spin in such a way that minimizes energy. In short, this means that planets like to reorient to place any extra mass closer to the equator -- and any mass deficits closer to the pole. For example, if a giant volcano were to grow on Los Angeles, Earth would reorient itself to place L.A. on the equator.
To understand polar wander on Pluto, one first has to realize that unlike Earth, whose spin axis is only slightly tilted so that the regions around the equator receive the most sunlight, Pluto is like a spinning top lying on its side. Therefore, the planet's poles get the most sunlight. Depending on the season, it's either one or the other, while Pluto's equatorial regions are extremely cold, all the time.
Because Pluto is almost 40 times farther from the sun than we are, it takes the little ball of rock and ice 248 Earth-years to complete one of its own years. At Pluto's lower latitudes near the equator, temperatures are almost as cold as minus 400 degrees Fahrenheit -- cold enough to turn nitrogen into a frozen solid.
Over the course of a Pluto year, nitrogen and other exotic gases condense on the permanently shadowed regions, and eventually, as Pluto goes around the sun, those frozen gases heat up, become gaseous again and re-condense on the other side of the planet, resulting in seasonal "snowfall" on Sputnik Planitia.
"Each time Pluto goes around the sun, a bit of nitrogen accumulates in the heart," Keane said. "And once enough ice has piled up, maybe a hundred meters thick, it starts to overwhelm the planet's shape, which dictates the planet's orientation. And if you have an excess of mass in one spot on the planet, it wants to go to the equator. Eventually, over millions of years, it will drag the whole planet over."
In a sense, Pluto is a (dwarf) planet whose shape and position in space are controlled by its weather.
"I think this idea of a whole planet being dragged around by the cycling of volatiles is not something many people had really thought about before," Keane said.
The two researchers used observations made during New Horizons' flyby and combined them with computer models that allowed them to take a surface feature such as Sputnik Planitia, shift it around on the planet's surface and see what that does to the planet's spin axis. And sure enough, in the models, the geographic location of Sputnik Planitia ended up suspiciously close to where one would expect it to be.
If Sputnik Planitia were a large positive mass anomaly -- perhaps due to loading of nitrogen ice -- it would naturally migrate to Pluto's tidal axis with regard to Charon, Pluto's largest moon, as it approaches a minimum energy state, according to Keane and Matsuyama. In other words, the massive accumulation of ice would end up where it causes the least wobble in Pluto's spin axis.
This phenomenon of polar wander is something that was discovered with Earth's moon and with Mars, as well, but in those cases it happened in the distant past, billions of years ago.
"On Pluto, those processes are currently active," Keane said. "Its entire geology -- glaciers, mountains, valleys -- seems to be linked to volatile processes. That's different from most other planets and moons in our solar system."
And not only that, the simulations and calculations also predicted that the accumulation of frozen volatiles in Pluto's heart would cause cracks and faults in the planet's surface in the exact same locations where New Horizons saw them.
The presence of tectonic faults on Pluto hint at the existence of a subsurface ocean at some point in Pluto's history, Keane explained.
"It's like freezing ice cubes," he said. "As the water turns to ice, it expands. On a planetary scale, this process breaks the surface around the planet and creates the faults we see today."
The paper is published alongside a report by Francis Nimmo of the University of California, Santa Cruz, and colleagues, who also consider the implications for Pluto's apparent reorientation. The authors of that paper agree with the idea that tidal forces could explain the current location of Sputnik Planitia, but in order for their model to work, a subsurface ocean would have to be present on Pluto today.
Read more at Science Daily
|Well-preserved buccal microwear surfaces in which buccal striations could be measured.|
Two species in the Paranthropus genus of early hominins, P. aethiopicus and P. boisei, co-existed for some time with early Homo species including H. ergaster, but seem to have had different diets. Previous isotopic analysis has supported the theory that while H. ergaster, which had relatively small jaws and teeth, consumed a lot of meat, Paranthropus species, which had massive lower jaws and molars with large chewing surfaces, may have specialized to eat a high proportion of fibrous, abrasive C4 plants. However, examination of wear patterns on the grinding surfaces of hominin teeth has not supported this theory. The authors of the present study aimed to resolve this discrepancy by gathering additional tooth wear data. They examined microscopic scratches on the cheek surfaces of teeth from 167 fossil specimens of Paranthropus and early Homo species from sites in Ethiopia, Kenya and Tanzania.
The researchers found that, contrary to the previous isotopic evidence, the scratch patterns on cheek surfaces of P. aethiopicus and P. boisei teeth suggested that their dietary habits 'did not involve chewing significant amounts of abrasive foods'. However, they note that these species might have eaten less abrasive, brittle C4 plants; which would be consistent with both the isotopic and the dental evidence. Meanwhile, the scratch patterns found on H. ergaster teeth suggest that they ate more abrasive foods that had been expected, which could indicate that early Homo species also underwent a dietary shift to C4 plants as they evolved. This study provides valuable additional evidence concerning the evolution and composition of the diets of Paranthropus and Homo species over time.
From Science Daily
|Lung cancer invades a healthy cell.|
The Chinese team, lead by oncologist Lu You at Sichuan University in Chengdu, used CRISPR/Cas9 to treat a patient with non-small-cell lung cancer as a part of a clinical trial. This could be the first step toward completely new cancer therapies.
Heralded as one of the biggest biotechnology breakthroughs of the century, the CRISPR/Cas9 technique allows scientists to repair broken genes more easily and more efficiently than previous methods. It starts with an RNA molecule that matches the DNA sequence of a targeted gene. The RNA works like a guide, bringing the enzyme Cas9 to the damaged bit of DNA, where it's used to snip out the damage, replace it or repair it.
The technique, first reported in Science in 2012 by Jennifer Doudna at the University of California, Berkeley, and Emmanuelle Charpentier, now at the Max Planck Institute for Infection Biology in Berlin, lets a researcher change any part of the DNA of any organism. It has the potential to cure diseases, engineer crops to withstand extreme environments and even eradicate pathogens.
After the Science paper was published, several scientists began experimenting with the technique. But then in 2015, scientists in Beijing used CRISPR to modify genes in a human embryo. The embryo was not allowed to develop into a human, but the implications were obvious. CRISPR could be used to modify human beings before they were born.
Shortly thereafter, the National Institutes of Health established the Recombinant DNA Advisory Committee to review and make recommendations on any research studies that involved using techniques like CRISPR on humans.
Although many scientists felt that taking a more conservative approach was important, it slowed progress. Meanwhile, researchers in China forged on.
In this latest advance, Dr. Lu and his team removed immune cells from a patient's blood. They used the CRISPR/Cas9 technique to disable a gene responsible for producing a protein, PD-1, that stops a cell from having an immune response. Cancer cells use the lack of an immune response to their advantage in order to grow and spread.
Lu and his team cultured cells with the modified genes in order to grow more and then injected them into the patient. The hope is that without the ability to produce a protein that stops an immune response, the cells could launch an effective attack against the cancer.
This is the first time that genes edited with the CRISPR/Cas9 technique have been injected into a human. Researchers in the United States want to be next.
"I think this is going to trigger 'Sputnik 2.0', a biomedical duel on progress between China and the United States, which is important since competition usually improves the end product," Carl June, who specializes in immunotherapy at the University of Pennsylvania in Philadelphia and led one of the earlier studies, told Nature.
At the moment, the only clinical study in the United States to get the green light from the Recombinant DNA Advisory Committee is one built around research developed in June's lab at UPenn. June and his colleagues used CRISPR/Cas-9 to genetically modify immune cells, known as T cells, to treat leukemia and other cancers.
Read more at Discovery News
The sea is believed to be buried 93- to 124 miles beneath Pluto's giant impact basin, known as Sputnik Planitia, which lies within the heart-shaped Tombaugh Regio.
The ocean is estimated to be 62 miles deep, said planetary scientist Francis Nimmo, with the University of California, Santa Cruz.
Evidence for the ocean, reported in a pair of papers in this week's Nature, comes from images and analysis of data collected by NASA's New Horizons spacecraft, which flew past Pluto, its primary moon Charon and four smaller moons in July 2015.
Scientists were trying to figure out how Sputnik Planitia formed and why it is located in its present position, roughly 18 degrees north of Pluto's equator.
The analysis suggests that billions of years ago Pluto was hit by a comet or Kuiper Belt object, forming a basin on the surface. The depression then filled with nitrogen ice, which caused the dwarf planet to roll over, stressing and cracking the crust in the process. Eventually the faults caused Pluto's mountains and canyons to form.
Computer models show the best explanation for how this occurred is if Pluto has an underground layer of slushy water pushing up against the thinned crust.
"If you put an extra weight on the surface of Pluto, Pluto will roll over to place the weight on the equator at a point directly opposite Charon. That point is very close to the location of Sputnik Planitia. So Sputnik Planitia must represent an extra weight — even though it's a hole in the ground," Nimmo wrote in an email to Seeker.
"This type of gravity anomaly with a thin crust and this extra mass of dense slushy ocean pushing up seems to be the most efficient explanation," added Massachusetts Institute of Technology planetary scientist Richard Binzel.
"We know there is water ice present at Pluto. We see it frozen on the surface. We see giant icebergs the size of mountains that have to be lifted up somehow, and know that water and water ice have to be active on Pluto. This is what gives us the idea of a slushy layer," Binzel told Seeker.
Pluto, which formed along with the rest of the solar system about 4.6 billion years ago, has enough internal heat left from the decay of naturally occurring radioactive materials to liquefy frozen water, the studies show.
Read more at Discovery News
When people as well as raptors want to find something, they do not just hold their head in one position and rivet their eyes to a single spot, even if they hone in on their target. Instead, the new research published in The Auk: Ornithological Advances shows that hunters and other searchers randomly change their head movements and direction of gaze.
It is a very animalistic behavior that we are not even really aware of in the moment, unless we make a conscious point of noting every one of our head turns and eye movements, which is near impossible.
"Researchers have hypothesized this visual search behavior arose deep in evolutionary time from the need for predators and prey to prevent each other from knowing where they would look next," senior author Suzanne Amador Kane of Haverford College told Seeker. "This has been compared to the hero and villain in an old movie dodging back and forth about a table, each trying to surprise the other."
To investigate the behavior, Amador Kane and her team studied the timing of head turns by birds of prey such as hawks, eagles and falcons as they searched for food in the wild. They used two sources of data: videos of wild birds filmed in the field, and video filmed by Shinta, who was wearing the mini video camera fitted into a small helmet.
Shinta's videos provided by falconer Robert Musters are below:
Falconer Robert Musters designed the tiny camera-holding helmet worn by Shinta, and is the man seen from her viewpoint in the videos.
Amador Kane said that, in order for us to better understand the process, we imagine a hunting bird making a decision to change its direction of gaze based on the visual info streaming in as it visually scans its environment.
"The longer it looks and finds no indication that prey is present, the less likely it will find prey initially and the more likely it is that looking in a different direction will be more profitable," she said. "However, if the predator gives up after a predictable time, the prey can use that regular timing in its own decisions about when to flee or break cover based on that information."
What actually happens then is "a compromise between these two factors, and is indeed similar to that found for human visual searches."
Graham Martin is a University of Birmingham professor and expert in raptor hunting behavior. He was not involved with the study.
Read more at Discovery News
Nov 15, 2016
Dr. Jonathan Chabout is the lead author of the paper, whose principal investigator is Dr. Erich Jarvis.
Dr. Jarvis and colleagues report the results of their investigation into the effect of a genetic mutation in the Forkhead box protein #2 (FOXP2) on the vocalization patterns of adult male mice. FOXP2 regulates speech production in humans. Individuals with deficiencies in FOXP2 protein have difficulty forming complex syllables and complex sentence construction.
Although mice are unable to communicate using speech in the same way as humans, they do vocalize as a means of communicating with each other. Therefore this study sought to determine whether FOXP2 deficiencies have similar consequences for communication by mice as they do for humans.
Dr. Jarvis suggests that this study supports the "continuum hypothesis," which is that FOXP2 affects the vocal production of all mammals and not just humans.
Dr. Jarvis' team investigated twenty-six (26) male mice bred to have a FOXP2 mutation the same as that found in humans with speech deficits, and twenty-four (24) "wildtype" male mice (i.e., mice with a normal level of FOXP2 protein).
Both types of male mice (the heterozygous mice containing the FOXP2 mutation and the wildtype mice) were placed in several unique contexts -- housed with an active wildtype female mouse, in proximity of only the urine of wildtype females, or housed with a sleeping female or sleeping male mouse. These particular contexts derived from prior research published by Chabout and colleagues in 2015.
This past study found that in these various social contexts, healthy males produced differences in the sequence and duration of the ultrasonic vocalizations (USVs), which are high-pitched sounds inaudible to humans, that mice make. In their new study, the investigators wished to determine if there was an effect of a FOXP2 deficiency on the communication patterns of mice.
The results showed that the FOXP2 heterozygotes have difficulty producing the complex vocal communication patterns that wildtype mice can create with ease -- as measured both by syllable length and the number of unique syllables produced over time. These divergences are particularly strong when comparing the communication of FOXP2 heterozygotes and wildtype males while in the presence of active female mice. In this context, the wildtype males were 3 times as likely as heterozygotes to produce the most complex syllable types and sequences available for review. Dr. Jarvis' team performed intricate statistical analyses to validate this finding, and their conclusion held true.
Following the conclusion of all recordings, Dr. Jarvis' team used a process known as transsynaptic tracing from vocal larynx muscles to compare the vocal brain regions of wildtype and heterozygote FOXP2 mice. This study revealed that the heterozygote's vocal motor neurons were more widely distributed across the cortex than was the case for wildtype mice. This evidence suggests that the FOXP2 mutation affects both the placement and functioning of the neurons connected to effective communication, from mice all the way to humans.
Read more at Science Daily
|A fog blanketed London in December 1952, killing as many as 12,000 people and puzzling researchers for decades. Texas A&M researchers believe they have solved the mystery.|
Texas A&M researcher Renyi Zhang, University Distinguished Professor and the Harold J. Haynes Chair of Atmospheric Sciences and Professor of Chemistry, along with graduate students Yun Lin, Wilmarie Marrero-Ortiz, Jeremiah Secrest, Yixin Li, Jiaxi Hu and Bowen Pan and researchers from China, Florida, California Israel and the UK have had their work published in the current issue of Proceedings of the National Academy of Sciences (PNAS).
In December of 1952, the fog enveloped all of London and residents at first gave it little notice because it appeared to be no different from the familiar natural fogs that have swept over Great Britain for thousands of years.
But over the next few days, conditions deteriorated, and the sky literally became dark. Visibility was reduced to only three feet in many parts of the city, all transportation was shut down and tens of thousands of people had trouble breathing. By the time the fog had lifted on Dec. 9, at least 4,000 people had died and more than 150,000 had been hospitalized. Thousands of animals in the area were also killed.
Recent British studies now say that the death count was likely far higher -- more than 12,000 people of all ages died from the killer fog. It has long been known that many of those deaths were likely caused by emissions from coal burning, but the exact chemical processes that led to the deadly mix of fog and pollution have not been fully understood over the past 60 years.
The 1952 killer fog led to the passage of the Clean Air Act in 1956 by the British Parliament and is still considered the worst air pollution event in the European history.
Through laboratory experiments and atmospheric measurements in China, the team has come up with the answers.
"People have known that sulfate was a big contributor to the fog, and sulfuric acid particles were formed from sulfur dioxide released by coal burning for residential use and power plants, and other means," Zhang says.
"But how sulfur dioxide was turned into sulfuric acid was unclear. Our results showed that this process was facilitated by nitrogen dioxide, another co-product of coal burning, and occurred initially on natural fog. Another key aspect in the conversion of sulfur dioxide to sulfate is that it produces acidic particles, which subsequently inhibits this process. Natural fog contained larger particles of several tens of micrometers in size, and the acid formed was sufficiently diluted. Evaporation of those fog particles then left smaller acidic haze particles that covered the city."
The study shows that similar chemistry occurs frequently in China, which has battled air pollution for decades. Of the 20 most polluted cities in the world, China is home to 16 of them, and Beijing often exceeds by many times the acceptable air standards set by the U.S. Environmental Protection Agency.
"The difference in China is that the haze starts from much smaller nanoparticles, and the sulfate formation process is only possible with ammonia to neutralize the particles," Zhang adds.
"In China, sulfur dioxide is mainly emitted by power plants, nitrogen dioxide is from power plants and automobiles, and ammonia comes from fertilizer use and automobiles. Again, the right chemical processes have to interplay for the deadly haze to occur in China. Interestingly, while the London fog was highly acidic, contemporary Chinese haze is basically neutral."
Read more at Science Daily
The man, called a "Siberian Robin Hood" by the local press, was likely a warrior of Mongolian origin who lived between 1200 and 1300 AD. The way he was buried suggests he was held in high respect.
According to the Siberian Times, the burial was found by local residents in a cliff near Kokorya, in the remote Altai Republic.
Wedged into a hole, the grave contained "the bones of an adult man, his birch bark quiver, arrow shafts and iron arrow heads, intricate ornaments and utensils made from the roots of trees, as well as the remnants of silk ribbons," the Siberian Times wrote.
The items are very well preserved due to the Siberian cold. The burial also contained birch bark linings for a saddle, the remains of a leather strap possibly used for attaching the quiver to the belt, and abundance of iron arrowheads and wooden arrow shafts.
"I can't say he was a 'Siberian Robin Hood.' Arrows are ordinary findings for medieval burials in the Altai. Almost all men used bows for hunting and battles," Nikita Konstantinov, head of the Museum of Gorno-Altaisk State University, told Seeker.
"The burial is interesting because of the decorated quiver," he added.
Made of two layers of birch bark — internal and external — the quiver had separate pockets for different types of arrows.
Although the bottom and other details aren't preserved, the quiver is unique. It features elaborate bone decorations with patterns that were popular in the territory of the Golden Horde, a division of the Mongol Empire which flourished from the mid-13th century to the end of the 14th century.
"There are no such quivers in the Altai, this one is unique," Konstantinov said.
Read more at Discovery News
To make his case, Shostak pointed to the path that humanity appears to be on. The human species invented the radio around 1900 and the computer in 1945, and it's already manufacturing relatively cheap devices with greater computing power than the human brain.
The development of true, strong artificial intelligence (AI) is therefore not too far off, experts have said. The famous futurist Ray Kurzweil, for example, has pegged 2045 as the year this world-changing "singularity" will hit.
"But maybe it takes to 2100, or 2150, or 2250. It doesn't matter," Shostak said in September during a presentation at the Dent:Space conference in San Francisco. "The point is, any society that invents radio, so we can hear them, within a few centuries, they've invented their successors. And I think that's important, because the successors are machines."
AI will interface with people's bodies for a while, but eventually humans will abandon the wetware and go fully digital, Shostak predicted.
"It'll be like — you build a four-cylinder engine. You put it in a horse to get a faster horse. And pretty soon you say, 'Look, let's get rid of the horse part and just build a Maserati,'" said Shostak, an astronomer at the Search for Extraterrestrial Intelligence (SETI) Institute in Mountain View, California. "So that's probably what's going to happen."
Humans' machine selves will get smarter and more capable incredibly quickly, he added. Humanity's present intelligence is the result of 4 billion years of Darwinian evolution, which uses random variation as its raw material and is not directed toward any particular goal. But the evolution of machine intelligence will be engineered and efficient, Shostak said.
"Once you invent a thinking machine, you say, 'Invent something better than you are,' and you build that. 'Design something better than you are,' and you build that, and so forth," he said.
This idea has serious implications for the search for intelligent alien life. Unlike Earth organisms, super-advanced extraterrestrial machines would not require water or other chemicals to survive, so they would not be tied to their ancestors' home worlds tightly at all, Shostak said. And journeying tremendous distances would not be a big deal to these machines, provided they could access enough energy and raw materials to keep repairing themselves over the millennia, he said.
"We continue to look in the directions of star systems that we think have habitable words, that have planets where biology could cook up and eventually turn into something clever like you guys," he told the Dent:Space audience. "But I don't think it's going to be that way."
Shostak said he isn't counseling his fellow SETI astronomers to stop investigating potentially Earth-like planets such as Proxima b, a recently discovered world that lies just 4.2 light-years away. (And simple life-forms could still inhabit such worlds even if their most intelligent inhabitants went digital and departed long ago, Shostak said.) But it may be a good idea to expand the search to regions of space that would seemingly be attractive to digital life-forms, he said — for example, places with lots of available energy, such as the centers of galaxies.
Read more at Discovery News
The discovery, reported in the journal Nature Communications, adds to the growing body of evidence that the excrement from at least certain animals, such as whales, can affect climate.
"This study highlights important connections between seabirds, atmospheric chemistry and climate that we don't yet fully understand," co-author Gregory Wentworth of the University of Toronto's Department of Chemistry told Seeker. "It's important to consider how changes in seabird population will affect the process."
Wentworth previously led a study that determined seabird colonies are significant sources of atmospheric ammonia in the Arctic during the summertime, when tens of millions of breeding bird pairs nest in the region. How their massive amount of waste relates to ammonia, which impacts climate, involves a chain of events that starts, not with birds, but with fish.
He explained that fish are rich in nitrogen. Seabirds consume fish, and so their excrement, known as guano, contains ample amounts of uric acid, a nitrogen-containing molecule. Uric acid, in turn, is broken down by microbes into ammonia, and this reduced-nitrogen gas is released into the atmosphere. There, ammonia molecules can cluster together with other gases, namely sulfuric acid and water vapor, to form very tiny solid aerosol particles.
The new study, led by Betty Croft of Dalhousie University's Department of Physics and Atmospheric Science, used ammonia emissions data for various seabirds to model how the resulting atmospheric particulate matter impacts cloud formation and cooling at Alert, Nunavut, in the Canadian Arctic. In addition to tufted puffins, the birds included dovekies, black-legged kittiwakes, thick-billed murres, Arctic terns, northern fulmars and 317 other seabird species.
These droplets are important, because they can make existing clouds more reflective of the incoming energy from the sun. That is when the temperature can start to fall.
"The cooling effects occur when the clouds are reflecting sunlight back into space," Wentworth explained. "This effect is largest for clouds over darker surfaces, such as the open ocean, and is relatively minor over bright surfaces like sea ice and snow."
Since the Arctic has experienced considerable warming in recent years, this literally cool process is a welcome find.
|"Guano Mountain" at Vancouver Island, British Columbia.|
It is because of our polluting ways that any possible beneficial cooling resulting from birds outside of the Arctic, such as seagulls soaring and splattering around beaches, is negated.
Croft explained that "in more polluted environments, the gas-phase ammonia has a greater tendency to just condense on to existing atmospheric particles, as opposed to forming any additional particles, which are key in the guano-to-particle-to-cloud process that we considered in the study."
Read more at Discovery News
Nov 14, 2016
|This is a red squirrel with leprosy on its ear.|
Once rampant in medieval Europe, leprosy dramatically declined by the end of the Middle Ages for reasons that are still unclear. About a century ago, leprosy in Europe virtually disappeared, at least among humans. Examining diseased red squirrels from England, Ireland, and Scotland, scientists at EPFL and the University of Edinburgh have now discovered that the same bacteria that cause leprosy in humans also infect red squirrels. The work is published in Science.
Leprosy is an infectious disease that mainly affects the skin, peripheral nerves, the upper respiratory tract, and the eyes. It is caused by the bacteria Mycobacterium leprae and the recently discovered Mycobacterium lepromatosis. One of the most ancient diseases, leprosy has had an enormous social impact across multiple cultures throughout history. Largely controlled today thanks to antibiotics, there are still over 200,000 new cases of leprosy reported each year worldwide.
A little-known fact is that leprosy also affects animals, such as armadillos, which have reportedly caused a few cases of animal-to-human (or "zoonotic") infections. Drawing from this evidence, the labs of Stewart Cole at EPFL and Anna Meredith at the University of Edinburgh carried out DNA tests on 110 red squirrels from England, Scotland, and Ireland. Some of these animals showed clinical symptoms of leprosy, while others did not; nonetheless, most were found to be infected with leprosy bacteria.
Surprisingly, red squirrels from Brownsea Island, off the south coast of England, were infected with a strain of M. leprae that is closely related to one found in a skeleton of a leprosy victim that was buried in Winchester 730 years ago, just 70 km from Brownsea Island.
On the other hand, red squirrels from Scotland and Ireland and the Isle of Wight (South England) were found to be infected with the other leprosy bacterium, M. lepromatosis. This species causes leprosy in humans in Mexico, and further analysis showed that the two strains from Mexico and Europe diverged from a common ancestor around 27,000 years ago.
"It was completely unexpected to see that centuries after its elimination from humans in the UK M. leprae causes disease in red squirrels," says Stewart Cole. "This has never been observed before."
The study shows how a pathogen can remain undetected in the environment even hundreds of years after it has been cleared from the human population. "The discovery of leprosy in red squirrels is worrying from a conservation perspective but shouldn't raise concerns for people in the UK," says Anna Meredith. "We need to understand how and why the disease is acquired and transmitted among red squirrels so that we can better manage the disease in this iconic species."
But is there a danger to humans? "There is no reason for panic," says Andrej Benjak, one of the paper's lead authors. "Autochthonous leprosy has not been detected in the UK in decades, though we cannot exclude the possibility of rare, unreported or misdiagnosed cases that originated within the UK." He suggests increasing efforts to monitor the disease, as part of the WHO's global Leprosy Surveillance Programme, where there is still room for improvement.
Read more at Science Daily
|Discoveries indicate mass fishing and therefore a semi-permanent settlement.|
Other spectacular finds include a 9,000 year-old pick axe made out of elk antlers. The discoveries indicate mass fishing and therefore a semi-permanent settlement.
"As geologists, we want to recreate this area and understand how it looked. Was it warm or cold? How did the environment change over time?" says Anton Hansson, PhD student in Quaternary geology at Lund University.
Changes in the sea level have allowed the findings to be preserved deep below the surface of Hanö Bay in the Baltic Sea.
The researchers have drilled into the seabed and radiocarbon dated the core, as well as examined pollen and diatoms. They have also produced a bathymetrical map that reveals depth variations.
"These sites have been known, but only through scattered finds. We now have the technology for more detailed interpretations of the landscape," says Anton Hansson.
"If you want to fully understand how humans dispersed from Africa, and their way of life, we also have to find all their settlements. Quite a few of these are currently underwater, since the sea level is higher today than during the last glaciation. Humans have always prefered coastal sites," concludes Hansson.
From Science Daily
"It's a discovery that is likely to be controversial," says Kathy Cullen, the senior researcher on a paper on the subject that was published recently in Nature Communications. She has been working on this problem for over a decade with her colleague Maurice Chacron who also teaches in McGill's Department of Physiology.
"What we've found is that there are two sensory channels that transmit information to the brain about how we move around in the world using fundamentally different approaches. No one has ever demonstrated anything of the kind before," says Cullen. "But what is even more exciting to us is that we believe that the different ways that each of these channels sends information to the brain is a legacy of the differences between needing to navigate in water and in air."
Two types of neural signaling to keep us in balance
By recording and analyzing the activity in the brains of macaques during movements experienced in their daily lives -- doing things like foraging, walking, running, climbing and grooming -- the researchers found that there were two very different kinds of signals being sent to their brains as the monkeys moved around.
"Scientists already knew that there were two different types of receptors that sense motion in the inner ears of animals that live on land, but we've never really understood why before," says Mohsen Jamali whose PhD research at McGill is responsible for the discovery. He is now a post-doctoral fellow at Harvard. "We found that it's because there are two very different kinds of signals that are being transmitted to neurons in the brain to keep us in balance. One is like the fluid stylings of a crooner sliding slowly from one note to the next, the other is rapid and very precisely timed -- a bit like the beat of a drum,as it responds to a guitar solo."
Changing sensory environments of move from sea to land
The researchers believe that the different kinds of signals used by these two channels to give us a sense of how we move around in the world are related to the major evolutionary changes in our pasts. They are, in fact, no less than echoes of the different strategies needed to navigate the changing sensory environments in which we were living.
"If you can imagine swimming in the sea, you have a sense of the resistance of water along with its muffling, almost viscous effect. So it makes sense that information about our movements would be transmitted to our brains using these smooth, slowly varying patterns that resemble the peaks and dips of sound in a singer's voice," says Chacron. "But because on land there is far less resistance than in the water, as we move around we need to be able to perceive and be prepared to react with extreme rapidity in order to keep our balance. That's where timing with millisecond precision becomes important."
Read more at Science Daily
Resting inside a brightly colored wooden sarcophagus, the mummy had been bound with linen stuck together with plaster.
"The tomb was uncovered at the southern enclosure wall of the Temple of Millions of Years," Mahmoud Afifi, head of the ancient Egyptian antiquities department of the ministry, said in a statement.
The temple was built on the west bank of the Nile near Luxor by Pharaoh Thutmosis III (1490-1436 BC), one of Egypt's greatest warrior kings. Also known as the "Napoleon of Egypt," he was the sixth Pharaoh of the Eighteenth Dynasty, the best known of all the dynasties of ancient Egypt as it boasted pharaohs such as Hatshepsut, Amenhotep III, Akhenaten and Tutankhamun.
The mummy is believed to be the body of a man named Amenrenef, who held the title of "Servant of the King's House." Amenrenef, however, did not live under Thutmosis III. His tomb likely dates from the Third Intermediate period around 1,000 BC, probably to the 21st Dynasty.
"When the temple was already not functioning, the area was used as a necropolis," Egyptologist Myriam Seco Álvarez, head of the Spanish archaeological team, told Seeker.
"Until now we knew about the necropolis under the temple dated to the Middle Kingdom, but we didn't know about the Late Period tombs and this one of the Third Intermediate Period," she added.
The 3,000-year-old mummy case features "many colorful decorations recalling religious symbols of ancient Egypt," the Egyptologist said.
Álvarez, who has been working at the Temple of Millions of Years since 2008, noted that the inscriptions and decorations include solar symbols, the protective goddesses Isis and Nephthys spreading their wings, the four sons of god Horus, and many other finely painted scenes.
"The mission will now study the tomb and its contents to find out more about its owner," Afifi said.
From Discovery News
The discovery, reported in the journal Paleontology, strengthens evidence that many dinosaurs and prehistoric birds were dazzling to look at and likely evolved flashy ornaments such as iridescent feathers to capture the attention of the opposite sex. The feathers possibly also served as camouflage, or helped in alarming potential predators or prey.
"A conservative estimate of what they would have looked like would be a primary black color with a glossy, iridescent sheen, much like what has been suggested for the non-avian dinosaur Microraptor," Jennifer Peteya of the University of Akron's Department of Biology and Integrated Bioscience Program told Seeker.
|Illustration of the small dinosaur Microraptor zhaoianus.|
Peteya and her team determined that the fossil belonged to an early enantiornithine bird, referring to a group of now-extinct birds that lived alongside dinosaurs and almost always had teeth and clawed "fingers" on their wings.
Both microscopic and chemical evidence suggest the iridescence. The bird's melanosomes, which are cellular structures that produce the color pigment melanin, were very long and thin and were arranged in a sheet-like end-to-end orientation.
These characteristics are associated with iridescent feathers in living birds, so the researchers believe that the ancient bird's feathers featured luminous colors when viewed from different directions. The orientation of the melanosomes wasn't quite as strong as it is for modern birds like peacocks and hummingbirds, so the effect would have been a bit subtler, the scientists suspect.
|Purple-throated Carib hummingbird feeding at Morne Diablotins National Park, Dominica.|
"In many species of modern birds, mate choice is determined by flashy feathers and ornaments such as these," Peteya said. "Males, for example, with longer ornamental feathers or flashier feathers are more likely to attract a female than duller males."
Iridescence often evolves later in a bird's life, tied to sexual maturity. In this case, however, the flashy features seem to have emerged when the bird was still relatively young. Perhaps these birds were very fast living, mating early in life, or safety took a back seat to attractiveness, since the iridescence could have grabbed the attention of predators as well as mates.
Read more at Discovery News