Nov 21, 2017

Righty blue whales sometimes act like lefties, study finds

A blue whale dives into the water off the California coast.
Blue whales are the largest animals in the world, with bodies that can weigh as much as 25 elephants and extend over the length of a basketball court. To support their hulking bodies, the whale use various acrobatic maneuvers to scoop up many individually tiny prey, filtering the water back out through massive baleen plates. In most cases, the whales roll to the right as they capture their prey, just as most people are right-handed. But, researchers reporting in Current Biology on November 20 now show that the whales shift directions and roll left when performing 360° barrel rolls in shallow water.

The findings offer the first evidence of "handedness" in blue whales, the researchers say. They also highlight the importance of studying animals in their natural three-dimensional environments for revealing phenomena that may be impossible to capture in a captive environment.

"We believe that this left-side bias is the result of the whales maintaining a visual connection with their prey with their right eye," says Ari Friedlaender at the University of California, Santa Cruz. "If the whales turned to the right on approach, they would lose sight of their prey and decrease the ability to forage successfully. By rolling to the left, the whales may be maintaining this visual connection to their prey."

"To the best of our knowledge, this is the first example where animals show different lateralized behaviors depending on the context of the task that is being performed," says study co-author James Herbert-Read from Stockholm University in Sweden.

Friedlaender and his colleagues have long studied blue whales' feeding behaviors in an attempt to understand how they can support their large bodies. In the new study, the researchers attached motion-sensing tags to 63 blue whales living off the coast of California to capture how the animals move as they engulf their prey.

In total, the researchers collected data on more than 2,800 rolling lunges for prey to find that the animals approach their prey using two different rolling behaviors. In some cases, they roll to the side and then back, turning 180° or less. In other cases, they go in for a complete barrel roll that takes them around full circle.

The evidence shows that individual whales have a preference as to whether they roll to the right or the left. The vast majority of the whales showed a preference for rolling to the right, much as more people show a preference for using their right hands. But, the whales also showed some flexibility in their approach. When the animals did a barrel roll in shallow water to attack a small patch of prey from below at a steep angle, they more often spun left, going against their general preference.

The findings are the first to demonstrate a left-side bias for a lateralized routine behavior, the researchers say. They also highlight blue whales' adaptability when it comes to feeding behaviors. The whales shift their foraging strategies depending on where they are feeding in the water column, how their prey are behaving, and how they need to maneuver to forage successfully.

"We were completely surprised by these findings, but when considering the means by which the whales attack smaller prey patches, the behavior really seems to be effective, efficient, and in line with the mechanisms that drive their routine foraging behaviors," Friedlaender says.

"While most other large baleen whales that lunge-feed can feed on both krill patches and small forage fish like anchovies and herring, blue whales feed almost exclusively on krill patches and seem to exhibit feeding strategies to maximize their intake of as many krill as possible with each energetically costly feeding event," adds co-author Dave Cade at Stanford University.

Read more at Science Daily

Rise in oxygen levels links to ancient explosion of life, researchers find

The photograph shows the Shingle Pass section in east central Nevada, where late Cambrian to Middle Ordovician (460 to 495 million years ago) limestone rocks are exposed. These strata were sampled for carbon and sulfur isotopic analysis in order to estimate atmospheric oxygen levels based on certain isotopic trends. At Shingle Pass, oxygen levels do not appear to increase until near the end of the evolving section (460 million years ago), and perhaps this is just about the spot where an abundance of macro fauna fossils begin to be seen, such as trilobites, corals and cephalopods.
Oxygen has provided a breath of fresh air to the study of the Earth's evolution some 400-plus million years ago.

A team of researchers, including a faculty member and postdoctoral fellow from Washington University in St. Louis, found that oxygen levels appear to increase at about the same time as a three-fold increase in biodiversity during the Ordovician Period, between 445 and 485 million years ago, according to a study published Nov. 20 in Nature Geoscience.

"This oxygenation is supported by two approaches that are mostly independent from each other, using different sets of geochemical records and predicting the same amount of oxygenation occurred at roughly the same time as diversification," said Cole Edwards, the principal investigator of a study conducted when he was a postdoctoral fellow in the lab under the paper's senior author, David Fike, associate professor in Earth and Planetary Sciences in Arts & Sciences. The other authors are Matthew Saltzman of Ohio State University and Dana Royer of Wesleyan University in Connecticut.

"We made another link between biodiversification and oxygen levels, but this time during the Ordovician where near-modern levels of oxygen were reached about 455 million years ago," said Edwards, assistant professor in geological and environmental sciences at Appalachian State in Boone, N.C. "It should be stressed that this was probably not the only reason why diversification occurred at that time. It is likely that other changes -- such as ocean cooling, increased nutrient supply to the oceans and predation pressures -- worked together to allow animal life to diversify for millions of years."

This explosion of diversity, recognized as the Great Ordovician Biodiversification Event, brought about the rise of various marine life, tremendous change across species families and types, as well as changes to the Earth, starting at the bottom of the ocean floors. Asteroid impacts were among the many disruptions studied as the reasons for such an explosion of change. Edwards, Fike and others wanted to continue to probe the link between oxygen levels in the ocean-atmosphere and diversity levels of animals through deep time.

Estimating such oxygen levels is particularly difficult: There is no way to directly measure the composition of ancient atmospheres or oceans. Time machines exist only in fiction.

Using geochemical proxies, high-resolution data and chemical signatures preserved in carbonate rocks formed from seawater, the researchers were able to identify an oxygen increase during the Middle and Late Ordovician periods -- and a rapid rise, at that. They cite a nearly 80-percent increase in oxygen levels where oxygen constituted about 14 percent of the atmosphere during the Darriwilian Stage (Middle Ordovician 460-465 million years ago) and increased to as high as 24 percent of the atmosphere by the mid-Katian (Late Ordovician 450-455 million years ago).

"This study suggests that atmospheric oxygen levels did not reach and maintain modern levels for millions of years after the Cambrian explosion, which is traditionally viewed as the time when the ocean-atmosphere was oxygenated," Edwards said. "In this research, we show that the oxygenation of the atmosphere and shallow ocean took millions of years, and only when shallow seas became progressively oxygenated were the major pulses of diversification able to take place."

The chemical signatures that served as proxies for dissolved inorganic carbon included data from geologic settings ranging from the Great Basin in the western United States, to the northern and eastern U.S., to Canada and its Maritimes, as well as Argentina in the Southern Hemisphere and Estonia in the Eastern Hemisphere. Nevada, Utah, Oklahoma, Missouri (New London north and Highway MM south of St. Louis), Iowa, Ohio, West Virginia and Pennsylvania were among the data points across the U.S.

The researchers concluded that it remained unclear whether the increased oxygenation had a direct effect on animal life, or even if it had a passive effect by, say, expanding the oxygen-rich ecospace. So it is difficult to resolve if temperature, increased oxygenation or something else served as the driver for biodiversification. But the findings showed that oxygen certainly was spiking during the times of some of the greatest change.

Read more at Science Daily

Astronomers reveal nearby stars that are among the oldest in our galaxy

Artist's concept of the Milky Way Galaxy.
Astronomers have discovered some of the oldest stars in our Milky Way galaxy by determining their locations and velocities, according to a study led by scientists at Georgia State University.

Just like humans, stars have a life span: birth, youth, adulthood, senior and death. This study focused on old or "senior citizen" stars, also known as cool subdwarfs, that are much older and cooler in temperature than the sun.

The Milky Way is nearly 14 billion years old, and its oldest stars developed in the early stage of the galaxy's formation, making them about six to nine billion years old. They're found in the halo, a roughly spherical component of the galaxy that formed first, in which old stars move in orbits that are highly elongated and tilted. Younger stars in the Milky Way rotate together along the galaxy's disc in roughly circular orbits, much like horses on a merry-go-round.

In this study, published in the November 2017 edition of The Astronomical Journal, astronomers conducted a census of our solar neighborhood to identify how many young, adult and old stars are present. They targeted stars out to a distance of 200 light years, which is relatively nearby considering the galaxy is more than 100,000 light years across. A light year is how far light can travel in one year. This is farther than the traditional horizon for the region of space that is referred to as "the solar neighborhood," which is about 80 light years in radius.

"The reason my horizon is more distant is that there are not a lot of senior citizens (old stars) in our solar neighborhood," said Dr. Wei-Chun Jao, lead author of the study and research scientist in the Department of Physics and Astronomy at Georgia State. "There are plenty of adult stars in our solar neighborhood, but there's not a lot of senior citizens, so we have to reach farther away in the galaxy to find them."

The astronomers first observed the stars over many years with the 0.9 meter telescope at the United State's Cerro Tololo Inter-American Observatory in the foothills of the Chilean Andes. They used a technique called astrometry to measure the stars' positions and were able to determine the stars' motions across the sky, their distances and whether or not each star had a hidden companion orbiting it.

The team's work increased the known population of old stars in our solar neighborhood by 25 percent. Among the new subdwarfs, the researchers discovered two old binary stars, even though older stars are typically found to be alone, rather than in pairs.

"I identified two new possible double stars, called binaries," Jao said. "It's rare for senior citizens to have companions. Old folks tend to live by themselves. I then used NASA's Hubble Space Telescope to detect both stars in one of the binaries and measured the separation between them, which will allow us to measure their masses."

Jao also outlined two methods to identify these rare old stars. One method uses stars' locations on a fundamental map of stellar astronomy known as the Hertzsprung-Russell (H-R) diagram. This is a classic technique that places the old stars below the sequence of dwarf stars such as the sun on the H-R diagram, hence the name "subdwarfs."

The authors then took a careful look at one particular characteristic of known subdwarf stars -- how fast they move across the sky.

"Every star moves across the sky," Jao said. "They don't stay still. They move in three dimensions, with a few stars moving directly toward or away from us, but most moving tangentially across the sky. In my research, I've found that if a star has a tangential velocity faster than 200 kilometers per second, it has to be old. So, based on their movements in our galaxy, I can evaluate whether a star is an old subdwarf or not. In general, the older a star is, the faster it moves."

They applied the tangential velocity cutoff and compared stars in the subdwarf region of the H-R diagram to other existing star databases to identify an additional 29 previously unidentified old star candidates.

In 2018, results from the European Space Agency's Gaia mission, which is measuring accurate positions and distances for millions of stars in the Milky Way, will make finding older stars much easier for astronomers. Determining the distance of stars is now very labor intensive and requires a lot of telescope time and patience. Because the Gaia mission will provide a much larger sample size, Jao says the limited sample of subdwarfs will grow, and the rarest of these rare stars -- binary subdwarfs -- will be revealed.

Read more at Science Daily

Liquid Water Might Not Be the Cause of Dark Streaks on Mars

Recurring slope linea on the surface of Mars
Bad news for microbes that want to make a home on Mars: A new study argues that dark streaks on the Martian surface are not caused by underground supplies of liquid water.

In 2015, observations by NASA's Mars Reconnaissance Orbiter revealed trace amounts of water (mixed with heavy doses of salts) on the Red Planet's surface. These "hydrated salts" corresponded with dark streaks on Martian hillsides called recurring slope lineae (RSL), which researchers had already identified as possible sites of liquid water rising to the surface.

Studies of RSL, and in particular the findings by the MRO, introduced the tantalizing possibility that there could be enough liquid water on the surface of Mars today to support microbial life.

But the new study shows that those dark RSL could simply be flows of sand and other granular material, according to a statement from NASA. In addition, the authors provide more reasons why the liquid water explanation does not fit with certain features of RSL.

"We've thought of RSL as possible liquid water flows, but the slopes are more like what we expect for dry sand," Colin Dundas, a research geologist with the US Geological Survey's Astrogeology Science Center and a lead author on the new study, said in the statement. "This new understanding of RSL supports other evidence that shows that Mars today is very dry."

However, neither study can fully explain all the features of the Martian RSL, and the authors of the new paper admit the mystery may not be solved until a rover or a human expedition can explore those regions directly.

This processed, false-color image of Mars' Hale Crater was taken by the High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter. The image highlights dark streaks on the Martian surface known as recurring slope lineae or RSL's.
Granular flows

Thousands of RSL sites have been identified on Martian slopes surface, in about 50 hilly regions spread out between the north and south midlatitudes, according to the statement from NASA. The streaks appear during warm seasons and shrink or disappear during winter. Similar features on Earth are only caused by "seeping water," officials said in the statement, but "how they form in the dry Martian environment remains unclear."

The new study offers an alternative explanation to flowing water.

When sand and other granular materials are lumped into piles, the material locks into place until the pile reaches a certain height. At that point, some of the grains begin to slip and flow smoothly down the sides, forming rivulets. Those rivers of material could appear darker than the material around them, according to the statement, and thus could explain the RSL.

And there's another key piece of evidence that the authors point to in support of this hypothesis: For a given type of granular material (such as sand), there is a specific angle at which those rivulets can form, and it's known as the "angle of repose." The authors show that the RSL that have been observed so far only appear on hillsides that reach the angle of repose for sand dunes. If the RSL sites were created by water, the authors postulate that these features should also appear on gentler slopes.

"The RSL don't flow onto shallower slopes, and the lengths of these are so closely correlated with the dynamic angle of repose, it can't be a coincidence," Alfred McEwen, a professor of planetary geology at the University of Arizona, Tucson, said in the statement. McEwen is the HiRISE Principal Investigator and a co-author of the new report.

The research also relies on models of slope steepness using data from the High Resolution Imaging Science Experiment (HiRISE) camera on MRO. The paper includes examinations of 151 RSL features at 10 sites. Another study, published in March, suggested that the RSL were caused by "dry avalanches."

A home for life

The findings do not negate the detection of hydrated salts by MRO, and liquid water may still play a role in the formation and seasonal evolution of RSL streaks, according to the paper. But, similar to a 2016 study, they contend the hypothesis that the water comes from beneath the surface.

The authors propose that the water detected in the RSL is sucked from the thin Martian atmosphere, rather than supplied by underground reserves. The increase in hydration could cause changes in the granular material on these slopes that triggers some of the flow that creates the dark streaks. The dark regions could also be the result of "changes in hydration," according to the statement.

Read more at Seeker

Nov 20, 2017

Secrets of Ebola unlocked in the heart of devastating outbreak

Yoshihiro Kawaoka, professor of pathobiological sciences at the UW-Madison School of Veterinary Medicine, meets with Ekundayo Thompson, vice chancellor of the University of Sierra Leone, while in the African nation to establish a partnership to study and fight Ebola while improving the research capacity and infrastructure of the University of Sierra Leone.
In a comprehensive and complex molecular study of blood samples from Ebola patients in Sierra Leone, published in Cell Host and Microbe, a scientific team led by the University of Wisconsin-Madison has identified signatures of Ebola virus disease that may aid in future treatment efforts.

Conducting a sweeping analysis of everything from enzymes to lipids to immune-system-associated molecules, the team -- which includes researchers from Pacific Northwest National Laboratory (PNNL), Icahn School of Medicine at Mount Sinai, the University of Tokyo and the University of Sierra Leone -- found 11 biomarkers that distinguish fatal infections from nonfatal ones and two that, when screened for early symptom onset, accurately predict which patients are likely to die.

With these results, says senior author Yoshihiro Kawaoka, a virology professor at the UW-Madison School of Veterinary Medicine, clinicians can prioritize the scarce treatment resources available and provide care to the sickest patients.

Studying Ebola in animal models is difficult; in humans, next to impossible. Yet, in Sierra Leone in 2014, a natural and devastating experiment played out. In September of that year, an Ebola outbreak like no other was beginning to surge in the West African nation. By December, as many as 400 Ebola cases would be reported there each week.

That fall, Kawaoka sought access to patient samples. He has spent a career trying to understand infectious diseases like Ebola -- how do they make people sick, how do bodies respond to infection, how can public health officials stay at least a step ahead?

"Here, there is a major outbreak of Ebola. It is very rare for us to encounter that situation," says Kawaoka, who is also a professor of virology at the University of Tokyo.

Yet blood samples were proving difficult to obtain and people continued to die.

Then, just weeks before Christmas, Kawaoka learned about a colleague in his very own department at UW-Madison, a research fellow from Sierra Leone named Alhaji N'jai, who was producing radio stories for people back home to help them protect themselves from Ebola. The pair forged a fortuitous partnership.

"He knows many people high up in the Sierra Leone government," says Kawaoka. "He is very smart and very good at explaining things in lay terms."

By Christmas, Kawaoka, N'jai and Peter Halfmann, a senior member of Kawaoka's team, were in Sierra Leone.

"On the first trip, Alhaji took me to Parliament and we talked to a special advisor to the president, then the vice chancellor of the University of Sierra Leone," says Kawaoka. "We got the support of the university, which helped us identify military hospitals and provided space. We went to the Ministry of Health and Sanitation and the chief medical officer and we explained what we hoped to do."

By February of 2015, Kawaoka and other select senior researchers on his team, including Amie Eisfeld, set up a lab in a military hospital responding to the outbreak in the capital city of Freetown (the researchers never entered patient wards). With the approval of patients and the government of Sierra Leone, health workers collected blood samples from patients after they were diagnosed with Ebola and at multiple points thereafter.

They obtained 29 blood samples from 11 patients who ultimately survived and nine blood samples from nine patients who died from the virus. The samples were transported to the lab where Kawaoka's experienced and expertly trained team inactivated the virus according to approved protocols. Blood samples were subsequently shipped to UW-Madison and partner institutions for analysis.

For comparison, the research team also obtained blood samples from 10 healthy volunteers with no exposure to Ebola virus.

"Our team studied thousands of molecular clues in each of these samples, sifting through extensive data on the activity of genes, proteins and other molecules to identify those of most interest," says Katrina Waters, a biologist at PNNL and a corresponding author of the study. "This may be the most thorough analysis yet of blood samples of patients infected with the Ebola virus."

The team found that survivors had higher levels of some immune-related molecules, and lower levels of others compared to those who died. Plasma cytokines, which are involved in immunity and stress response, were higher in the blood of people who perished. Fatal cases had unique metabolic responses compared to survivors, higher levels of virus, changes to plasma lipids involved in processes like blood coagulation, and more pronounced activation of some types of immune cells.

Pancreatic enzymes also leaked into the blood of patients who died, suggesting that damage from these enzymes contributes to the tissue damage characteristic of fatal Ebola virus disease.

And, critically, the study showed that levels of two biomarkers, known as L-threonine (an amino acid) and vitamin D binding protein, may accurately predict which patients live and which die. Both were present at lower levels at the time of admission in the patients who ultimately perished.

"We want to understand why those two compounds are discriminating factors," says Kawaoka. "We might be able to develop drugs."

When Ebola virus leads to death, experts believe it is because of overwhelming viral replication. Symptoms of infection include severe hemorrhaging, vomiting and diarrhea, fever and more.

Kawaoka and his collaborators hope to better understand why there are differences in how patients' bodies respond to infection, and why some people die while others live. The current study is part of a larger, multicenter effort funded by the National Institutes of Health.

"The whole purpose is to study the responses of human and animal bodies to infection from influenza, Ebola, SARS and MERS, and to understand how they occur," Kawaoka explains. "Among the various pathways, is there anything in common?"

In the current Ebola study, the team found that many of the molecular signals present in the blood of sick, infected patients overlap with sepsis, a condition in which the body -- in response to infection by bacteria or other pathogens -- mounts a damaging inflammatory reaction.

And the results contribute a wealth of information for other scientists aimed at studying Ebola, the study authors say.

Read more at Science Daily

Theory: Flexibility is at the heart of human intelligence

The more readily the brain forms and reforms its connectivity in response to changing needs, the better it works, according to Aron Barbey, author of the paper.
Centuries of study have yielded many theories about how the brain gives rise to human intelligence. Some neuroscientists think intelligence springs from a single region or neural network. Others argue that metabolism or the efficiency with which brain cells make use of essential resources are key.

A new theory, published in the journal Trends in Cognitive Sciences, makes the case that the brain's dynamic properties -- how it is wired but also how that wiring shifts in response to changing intellectual demands -- are the best predictors of intelligence in the human brain.

"When we say that someone is smart, we understand intuitively what that means," said University of Illinois psychology professor Aron Barbey, the author of the new paper. "Usually, we're referring to how good they are at making decisions and solving particular types of problems. But recently in neuroscience, there's been a focus on understanding in biological terms how general intelligence arises." That requires studying the structural and functional characteristics of the brain.

Scientists have long understood that the brain is modular, with different regions supporting specific abilities, Barbey said.

"For example, brain regions within the occipital lobe at the back of the brain are known to processes visual information," he said. But interpreting what one sees requires the integration of information from other brain modules.

"To identify an object, we also must classify it. That doesn't depend only on vision. It also requires conceptual knowledge and other aspects of information processing, which are supported by other brain regions," he said. "And as the number of modules increases, the type of information represented in the brain becomes increasingly abstract and general."

Scientists have struggled to understand how the brain organizes itself and have tried to identify a structure or region that performs that function.

"The prefrontal cortex, a structure at the front of the brain, for example, has expanded dramatically over the course of human evolution," Barbey said. Because this brain region is known to support several higher-order functions such as planning and organizing one's behavior, scientists have suggested that the prefrontal cortex drives general intelligence.

"But really, the entire brain -- its global architecture and the interactions among lower- and higher-level mechanisms -- is required for general intelligence," Barbey said.

Brain modules provide the basic building blocks from which larger, "intrinsic connectivity networks" are constructed, Barbey said. Each network includes multiple brain structures that are activated together when a person engages a particular cognitive skill.

"For example, the frontoparietal network is activated when attention is focused on external cues, the salience network is engaged when attention is directed to relevant events, and the default mode network is recruited when attention is focused internally," he said.

Neural networks are made up of two types of connections that are believed to support two types of information processing, Barbey said.

"There are the pathways that encode prior knowledge and experience, which we call 'crystallized intelligence.' And there are adaptive reasoning and problem-solving skills that are quite flexible, called 'fluid intelligence,'" he said.

Crystallized intelligence involves robust connections, the result of months or years of neural traffic on well-worn pathways. Fluid intelligence involves weaker, more transient pathways and connections that are formed when the brain tackles unique or unusual problems.

"Rather than forming permanent connections, we are constantly updating our prior knowledge, and this involves forming new connections," Barbey said. The more readily the brain forms and reforms its connectivity in response to changing needs, the better it works, he said.

Although researchers have known that flexibility is an important characteristic of human brain function, only recently has the idea emerged that flexibility provides the basis for human intelligence, he said.

Read more at Science Daily

Human evolution was uneven and punctuated

Interior view of the cave and excavation trench as of the end of the 2012 field season.
Neanderthals survived at least 3,000 years longer than we thought in Southern Iberia -- what is now Spain -- long after they had died out everywhere else, according to new research published in Heliyon.

The authors of the study, an international team from Portuguese, Spanish, Catalonian, German, Austrian and Italian research institutions, say their findings suggest that the process of modern human populations absorbing Neanderthal populations through interbreeding was not a regular, gradual wave-of-advance but a "stop-and-go, punctuated, geographically uneven history."

Over more than ten years of fieldwork, the researchers excavated three new sites in southern Spain, where they discovered evidence of distinctly Neanderthal materials dating until 37,000 years ago.

"Technology from the Middle Paleolithic in Europe is exclusively associated with the Neanderthals," said Dr. João Zilhão, from the University of Barcelona and lead author of the study. "In three new excavation sites, we found Neanderthal artefacts dated to thousands of years later than anywhere else in Western Europe. Even in the adjacent regions of northern Spain and southern France the latest Neanderthal sites are all significantly older."

The Middle Paleolithic was a part of the Stone Age, and it spanned from 300,000 to 30,000 years ago. It is widely acknowledged that during this time, anatomically modern humans started to move out of Africa and assimilate coeval Eurasian populations, including Neanderthals, through interbreeding.

According to the new research, this process was not a straightforward, smooth one -- instead, it seems to have been punctuated, with different evolutionary patterns in different geographical regions.

In 2010, the team published evidence from the site of Cueva Antón in Spain that provided unambiguous evidence for symbolism among Neanderthals. Putting that evidence in context and using the latest radiometric techniques to date the site, the researchers show Cueva Antón is the most recent known Neanderthal site.

"We believe that the stop-and-go, punctuated, uneven mechanism we propose must have been the rule in human evolution, which helps explaining why Paleolithic material culture tends to form patterns of geographically extensive similarity while Paleolithic genomes tend to show complex ancestry patchworks," commented Dr. Zilhão.

The key to understanding this pattern, says Dr. Zilhão, lies in discovering and analyzing new sites, not in revisiting old ones. Although finding and excavating new sites with the latest techniques is time-consuming, he believes it is the approach that pays off.

Read more at Science Daily

Recovery of West Coast marine mammals boosts consumption of chinook salmon

While the recovery of marine mammals represents a conservation success, it creates complex tradeoffs for managers also charged with protecting the salmon they prey on.
Recovering populations of killer whales, sea lions and harbor seals on the West Coast have dramatically increased their consumption of chinook salmon in the last 40 years, which may now exceed the combined harvest by commercial and recreational fisheries, a new study finds.

While the recovery of marine mammals represents a conservation success, it creates complex tradeoffs for managers also charged with protecting the salmon they prey on, the study concludes. The U.S. Marine Mammal Protection Act of 1972 protects all marine mammals, including whales and pinnipeds (seals and sea lions) within the waters of the United States. and the Endangered Species Act protects nine West Coast populations of chinook salmon.

The study was published today in the journal Scientific Reports. The findings resulted from a collaboration of federal, state and tribal scientists in the Pacific Northwest, including Oregon State University and NOAA Fisheries. The research was designed in part to understand the pressures on chinook salmon consumed by southern resident killer whales, which in contrast to other killer whale populations are endangered and show few signs of recovery.

Southern residents spend much of the year in the inland waters of Washington and consume about the same volume of salmon today as they did 40 years ago, the study found. The study suggests that, at least in recent years, competition with other marine mammals may be more of a problem for southern residents than competition with human fisheries.

"We have been successful at restoring and improving the population status of protected marine mammals," said Brandon Chasco, a doctoral candidate at Oregon State University and lead author of the study. "But now we have the potential for protected seals and sea lions to be competing with protected killer whales, and all of which consume protected chinook salmon."

The study used models to estimate marine mammal consumption of chinook salmon based on several assumptions about their diet and the size and weight of salmon. The researchers estimate that from 1975 to 2015, the yearly biomass of chinook salmon consumed by pinnipeds (sea lions and harbor seals) and killer whales increased from 6,100 to 15,200 metric tons, and from five to 31.5 million individual salmon.

Over the same time span, they found that annual fisheries harvest decreased from 16,400 to 9,600 metric tons, and from 3.6 million to 2.1 million individuals.

Overall, several growing populations of resident killer whales in Canada and southeast Alaska are estimated to consume the largest biomass of chinook salmon, but harbor seals consume the largest number of individuals, including juvenile chinook salmon, according to the study.

Salmon are anadromous: They migrate from home streams to the ocean as juveniles, and return a few years later as adults to spawn. Many of the salmon from the West Coast migrate as far as Alaska, and are subject to predation during both their northward and southward migrations, making southern stocks of chinook salmon susceptible to a larger gauntlet of predators.

Salmon recovery programs underway up and down the West Coast have boosted numbers of wild salmon, the research found. However, increased predation by recovering marine mammals may be offsetting reductions in recreational and commercial harvests, and "masking the success of coast-wide recovery efforts," the scientists wrote.

Isaac Kaplan, a research fishery biologist at NOAA Fisheries' Northwest Fisheries Science Center and a coauthor on the study, said the researchers quantified only one of many challenges to chinook salmon recovery.

The better we understand the different obstacles to salmon recovery, the better we can account for them as we plan and carry out recovery programs," Kaplan said. "Recovery efforts must account for all of these challenges, and we're providing more details about one important part of that picture."

The Columbia River has previously been identified as an area with high marine mammal consumption of salmon, specifically by seals and sea lions in the estuary. The researchers found that in 2015 in the Columbia River, harbor seals on the river consumed 14 metric tons of chinook salmon, compared to 219 and 227 metric tons consumed by California and Steller sea lions, respectively.

Read more at Science Daily

Nov 17, 2017

Lava or not, exoplanet 55 Cancri e likely to have atmosphere

The super-Earth exoplanet 55 Cancri e, depicted with its star in this artist's concept, likely has an atmosphere thicker than Earth's but with ingredients that could be similar to those of Earth's atmosphere.
Twice as big as Earth, the super-Earth 55 Cancri e was thought to have lava flows on its surface. The planet is so close to its star, the same side of the planet always faces the star, such that the planet has permanent day and night sides. Based on a 2016 study using data from NASA's Spitzer Space Telescope, scientists speculated that lava would flow freely in lakes on the starlit side and become hardened on the face of perpetual darkness. The lava on the dayside would reflect radiation from the star, contributing to the overall observed temperature of the planet.

Now, a deeper analysis of the same Spitzer data finds this planet likely has an atmosphere whose ingredients could be similar to those of Earth's atmosphere, but thicker. Lava lakes directly exposed to space without an atmosphere would create local hot spots of high temperatures, so they are not the best explanation for the Spitzer observations, scientists said.

"If there is lava on this planet, it would need to cover the entire surface," said Renyu Hu, astronomer at NASA's Jet Propulsion Laboratory, Pasadena, California, and co-author of a study published in The Astronomical Journal. "But the lava would be hidden from our view by the thick atmosphere."

Using an improved model of how energy would flow throughout the planet and radiate back into space, researchers find that the night side of the planet is not as cool as previously thought. The "cold" side is still quite toasty by Earthly standards, with an average of 2,400 to 2,600 degrees Fahrenheit (1,300 to 1,400 Celsius), and the hot side averages 4,200 degrees Fahrenheit (2,300 Celsius). The difference between the hot and cold sides would need to be more extreme if there were no atmosphere.

"Scientists have been debating whether this planet has an atmosphere like Earth and Venus, or just a rocky core and no atmosphere, like Mercury. The case for an atmosphere is now stronger than ever," Hu said.

Researchers say the atmosphere of this mysterious planet could contain nitrogen, water and even oxygen -- molecules found in our atmosphere, too -- but with much higher temperatures throughout. The density of the planet is also similar to Earth, suggesting that it, too, is rocky. The intense heat from the host star would be far too great to support life, however, and could not maintain liquid water.

Hu developed a method of studying exoplanet atmospheres and surfaces, and had previously only applied it to sizzling, giant gaseous planets called hot Jupiters. Isabel Angelo, first author of the study and a senior at the University of California, Berkeley, worked on the study as part of her internship at JPL and adapted Hu's model to 55 Cancri e.

In a seminar, she heard about 55 Cancri e as a potentially carbon-rich planet, so high in temperature and pressure that its interior could contain a large amount of diamond.

"It's an exoplanet whose nature is pretty contested, which I thought was exciting," Angelo said.

Spitzer observed 55 Cancri e between June 15 and July 15, 2013, using a camera specially designed for viewing infrared light, which is invisible to human eyes. Infrared light is an indicator of heat energy. By comparing changes in brightness Spitzer observed to the energy flow models, researchers realized an atmosphere with volatile materials could best explain the temperatures.

There are many open questions about 55 Cancri e, especially: Why has the atmosphere not been stripped away from the planet, given the perilous radiation environment of the star?

"Understanding this planet will help us address larger questions about the evolution of rocky planets," Hu said.

Read more at Science Daily

On the origins of star stuff: Shedding new light on origin of anti-matter

The HAWC Observatory sits at an elevation of 13,500 feet, flanking the Sierra Negra volcano inside Pico de Orizaba National Park in the Mexican state of Puebla. Its more than 300 water tanks can detect cascades of particles initiated by high-energy packets of light called gamma rays.
A mountaintop observatory about four hours east of Mexico City, built and operated by an international team of scientists, has captured the first wide-angle view of gamma rays emanating from two rapidly spinning stars. The High-Altitude Water Cherenkov (HAWC) Gamma-Ray Observatory offers perspective on the very high energy light streaming from our stellar neighbors and casts serious doubt on one possible origin for a mysterious excess of anti-matter particles near Earth.

In 2008, a space-borne detector measured an unexpectedly high number of positrons -- the anti-matter cousins of electrons -- in orbit. Ever since, scientists have debated the cause of the anomaly, split over two competing theories of its origin. Some suggested a simple explanation: The extra particles might be coming from nearby collapsed stars called pulsars, which spin around several times a second and throw off electrons, positrons and other matter with violent force. Others speculated that the extra positrons have an exotic origin, perhaps coming from as-yet undetected processes involving dark matter -- the invisible but pervasive substance seen so far only through its gravitational pull.

"This new measurement is tantalizing because it strongly disfavors the idea that these extra positrons are coming to Earth from two nearby pulsars, at least when you assume a relatively simple model for their propagation," says Jordan Goodman, professor of physics at the University of Maryland and the lead investigator and US spokesperson for the HAWC collaboration. "Our measurement doesn't decide the question in favor of dark matter, but any new theory that attempts to explain the excess using pulsars will need to match the new data."

Using this new data from the HAWC observatory, researchers made the first detailed measurements of two pulsars previously identified as possible sources of the excess. By catching and counting particles of light streaming from these nearby stellar engines, the HAWC collaboration showed that the two pulsars are unlikely to be the origin of the positron excess. Despite being the right age and the right distance from Earth, the pulsars are surrounded by an extended murky cloud from which positrons can't escape in great numbers, according to results published this week in Science.

Petra Huentemeyer, associate professor physics at Michigan Technological University and founding member of the HAWC collaboration, started working with her former PhD student, Hao Zhou, on the related analysis of HAWC data while he was a postdoc at Michigan Tech in 2016.

"Our analysis does not support previous claims that the two nearby pulsars are responsible for the excess of positrons detected by two space-born telescopes, the Italian-lead PAMELA project and the AMS-02 detector of NASA," she says.

Some researchers posit that the positrons are produced in dark matter interactions.

"There are all kinds of efforts all over the globe to detect dark matter directly," she says. "Dark matter is difficult to detect. Dark matter is elusive. We don't see it. The reason we think it exists is because if you take what we know about gravitation and then look at the velocity of stars traveling around the center of disk galaxies, they are not traveling at the speeds we expect from visible matter. There must be dark, non-light emitting mass somewhere that causes this from what we understand about gravitation."

While the results in the Science paper do not affirm the detection of dark matter, they do confirm that positron excess is not explained by a pulsar nebula throwing off the particles.

Looking for Answers

The HAWC Observatory sits at an elevation of 13,500 feet, flanking the Sierra Negra volcano inside Pico de Orizaba National Park in the Mexican state of Puebla. More than 300 massive water tanks sit waiting at the site for cascades of particles initiated by high-energy packets of light called gamma rays -- many of which have more than a million times the energy of a dental X-ray.

When these gamma rays smash into the upper atmosphere, they blast apart atoms in the air, producing a shower of particles that moves at nearly the speed of light toward the ground. When this shower reaches HAWC's tanks, it produces coordinated flashes of blue light in the water, allowing researchers to reconstruct the energy and cosmic origin of the gamma ray that kicked off the cascade.

This measurement wouldn't have been possible without HAWC's wide view. It continuously scans about one-third of the sky overhead, which provided researchers with a broad view of the space around the pulsars.

"Thanks to its wide field of view, HAWC provides unique measurements on the very-high-energy gamma-ray profiles caused by the particle diffusion around nearby pulsars, which allows us to determine how fast the particles diffuse more directly than previous measurements," says Hao Zhou, now a scientist at the Los Alamos National Laboratory in New Mexico and Michigan Tech alumnus.

Zhou, one of the paper's corresponding authors, is responsible for developing the particle diffusion model and calculating the gamma-ray emission morphology around the two pulsars in HAWC data. He fit this model to the data to constrain the physical parameter about these sources, which describes how fast a particle diffuses away from its source.

As with an ordinary camera, collecting lots of light allows HAWC to build sharp images of individual gamma-ray sources. The highest energy gamma rays originate in the graveyards of big stars, such as the spinning pulsar remnants of supernovae. But that light doesn't come from the stars themselves. Instead, it's created when the spinning pulsar accelerates particles to extremely high energies, causing them to smash into lower-energy photons left over from the early universe.

The size of this stellar debris field, measured by the patch of sky that glows bright in gamma rays, tells researchers how quickly matter moves relative to a local astrophysical engine -- in this case, the nearby pulsars. This, in turn, enables researchers to estimate how quickly positrons are moving and how many positrons could have reached Earth from a given source. Using the most complete catalog of HAWC data to date, scientists have determined that the nearby pulsar Geminga and its unnamed sister are not sources of the positron excess. Even though the two pulsars are old enough and close enough to account for the excess, matter isn't drifting away from the pulsars fast enough to have reached the Earth.

Read more at Science Daily

Experimental Patch Could Ease Allergic Reactions to Peanuts

Having a food allergy requires more than a change in diet. For many people with a moderate to severe allergy, it requires a change in lifestyle.

In the United States, one of the most common food allergies is peanuts, an ingredient found in everything from lunch sandwiches to chili. In 2014, two percent of children in the United States under the age of 18 had a peanut allergy. It is the most common cause of anaphylaxis, a reaction in which a person experiences itchiness, swelling of the throat, plummeting blood pressure, fainting, or vomiting. When severe reactions are not treated with an emergency injection of epinephrine, the effect can sometimes be fatal.

While there is no cure for a peanut allergy, scientists are working on various treatments that can at least reduce the severity of reactions to the nut. Immunotherapy, where the patient is exposed to very small amounts of peanut protein over time, has garnered the attention of the science community in the past decade. While many of these studies have focused on oral doses of peanut protein — taken in a pill, for example — a new clinical trial shows that one solution may be skin deep.

The study, published in the Journal of the American Medical Association, on more than 200 peanut-allergic patients. Hugh Sampson of the Icahn School of Medicine at Mount Sinai School in New York led the research. Sampson is also the part-time, chief scientific officer at DBV Technologies, which makes the Viaskin Peanut patch and funded the study.

For the study, 221 participants between the ages of 6 and 55 years old were divided into four groups. One group received a placebo patch, which contained no peanut protein. The second, third, and fourth groups wore peanut patches containing either 50, 100, or 250 micrograms of peanut protein. The patients wore the patch on the back of their arm or their back every day for a year. In the end, 97 percent of the study participants — 207 patients — completed the full year.

The patch resembles a small round Band-Aid. When the patch is applied, the body’s natural water loss helps the peanut protein absorb the peanut protein inside, which is then absorbed into the skin and picked up by Langerhans cells. These cells then transport the protein to regional lymph nodes, where they educate regulatory T cells that might lessen an allergic response.

Sampson noted that the amount of peanut protein used in the study was very small when compared to the amounts used in other trials for oral immunotherapies. One oral immunotherapy, for example, gave patients up to two grams of peanut protein.

To be classified as a “responder” to the patch treatment, patients had to be able to tolerate 1,000 milligrams of the peanut protein at the end of the year, or 10 times more peanut protein than the amount that initially triggered their reactions at the beginning of the study.

After a year, a significant number of responders in the group wore the patch with 250 micrograms of peanut protein when compared to those wearing the placebo patch. There was no significant difference between those wearing the patches with 50 or 100 micrograms and the placebo group.

While Sampson said the results were in line with what his team was expecting, he added that there were some interesting findings when looking at the different age groups.

Children, or those 6 to 11 years old, had a better response to the patch when compared to the adolescent and adult groups. The result could be because of where the patch was placed — the patch was placed on the backs of the children while others wore the patch on the back of their arms — or the number of Langerhans cells exposed to the patch.

“We know that the Langerhans cells that pick up the protein tend to congregate around the hair follicle,” said Sampson. “Basically, you get so many hair follicles, and when you get older they spread out. So, it could be that using the same sized patch on an adult verses a child could mean that you’re not exposing as many Langerhans cells in an adult as you would a child.”

Read more at Seeker

Passenger Pigeon DNA Shows How Large, Stable Populations Can Quickly Go Extinct

A male passenger pigeon, estimated to sell for 8,000-12,000 GBP, is displayed at Summers Place Auctions on November 19, 2015 in Billingshurst, England.
The passenger pigeon was once the most abundant bird in North America, numbering between 3–5 billion. John Muir and many other naturalists were fascinated by these large, intelligent birds that often would passager, according to the French, or pass by, while migrating.

Muir devoted five full pages to passenger pigeons in his autobiography, mentioning that "the air was literally filled with pigeons" and the "continued buzz of wings" lulled him to sleep.

Over the course of Muir's lifetime, however, passenger pigeons died by the millions. In 1914 — the year of his own death — only one was left. Martha, as she was called, died on September 1 of that year at the Cincinnati Zoo, marking the species's extinction.

What lives on is a cautionary tale, according to a new genetic study on the birds published in the journal Science. Their DNA provides evidence that even large, stable populations can be at risk of extinction if rapid environmental change occurs.

"When passenger pigeon populations were large, there was natural selection for advantageous genes and against deleterious genes — both forms were highly efficient," senior author Beth Shapiro of the University of California, Santa Cruz told Seeker. "However, selection always works within a particular environment."

"In this case," she continued, "that environment was living in huge flocks. When the flocks became suddenly tiny — thanks to human hunting — these adaptations to life in large populations were suddenly of no use to the birds."

Female and male passenger pigeons from the collections of the Royal Ontario Museum
Shapiro, lead author Gemma Murray, and their international team were granted access to collections of passenger pigeons in museums. To cause minimal damage, the researchers extracted DNA from toe pads or bone samples of 84 of the birds.

The researchers then extracted DNA from four band-tailed pigeons. The band-tailed pigeon — a sociable bird with a mellow coo — is common in forests of the Pacific Coast and Southwest and is the closest living relative of the passenger pigeon.

A comparison of the two species' nuclear genomes revealed that the once-large population of passenger pigeons allowed for faster adaptive evolution than what is seen in band-tailed pigeons. High-diversity regions of passenger pigeon underwent stronger and faster genetic selection to remove harmful mutations and to maintain advantageous genes.

In short, passenger pigeons were almost perfectly adapted to their habitat and way of life.

The researchers were surprised to see that passenger pigeon populations were large even throughout the last ice age.

“This meant that these birds must have had both a very broad diet and a tremendous capacity to adapt to the enormous ecological changes that occurred as climate warmed into the present day," Shapiro said.

The apparent idyllic life of the passenger pigeon took a drastic turn for the worse when humans — first Native Americans, then Europeans — arrived in the Americas.

Because the meaty birds were close-knit and existed in large flocks, hunters could easily kill many at a time with little effort. By the 19th century, pigeon hunting intensified with growing demand for what was then considered to be cheap and good eats.

Passenger pigeons that survived the blood bath were reduced to living in small, isolated populations.

"Perhaps it was harder for them to find food, find a mate, and to do what it meant to be a passenger pigeon," Shapiro said. "If the decline had been slower, it is possible that passenger pigeons would have gradually adapted to their new ecological state."

Humans did not just hunt the birds. They also destroyed their habitat.

“The deforestation that was going on in the 19th century,” said Murray, “would have also had an impact, since passenger pigeons lived in forests and woodlands and ate nuts from trees."

With little time to adapt to the sudden changes, passenger pigeons went into a gradual decline from about 1800 to 1870, followed by a rapid decline between 1870 and 1890. The last confirmed passenger pigeon in the wild was thought to have been shot in 1901.

Band-tailed pigeons
Passenger pigeons and band-tailed pigeons co-existed, but did not interbreed, Shapiro said. She explained that the Rocky Mountains, which seem to be a barrier for band-tailed pigeons today, kept the two species apart.

Band-tailed pigeons may have survived, Murray said, because they form much smaller flocks and are less of a social species than passenger pigeons. “These features might make band-tailed pigeons more resilient than passenger pigeons to extinction, since they might allow them to live more successfully in smaller and more isolated populations," she said.

Read more at Seeker

Nov 16, 2017

Floating droplets: How droplets can 'levitate' on liquid surfaces

Visualization of vortices in a drop of silicone oil sitting on a warm bath. The temperature difference generates a recirculating flow that is visualized by shining a green laser light on fluorescent particles that are added as passive tracers within the drop.
A drop or two of cold cream in hot coffee can go a long way toward improving one's morning. But what if the two liquids didn't mix?

MIT scientists have now explained why under certain conditions a droplet of liquid should not coalesce with the liquid surface below. If the droplet is very cold, and the bath sufficiently hot, then the droplet should "levitate" on the bath's surface, as a result of the flows induced by the temperature difference.

The team's results, published today in the Journal of Fluid Mechanics, offer a detailed, mathematical understanding of drop coalescence, which can be observed in everday phenomena, from milk poured in coffee to raindrops skittering across puddles, and sprays created in surf zones.

The results may help researchers understand how biological or chemical substances are spread by rain or other sprays in nature. They could also serve as a guide for droplet-based designs, such as in microfluidic chips, in which droplets carrying various reagents can be designed to mix only in certain locations in a chip, at certain temperatures. With this new understanding, researchers could also engineer droplets to act as mechanical ball bearings in zero-gravity environments.

"Based on our new theory, engineers can determine what is the initial critical temperature difference they need to maintain two drops separately, and what is the maximum weight that a bearing constructed from these levitating drops would be able to sustain," says Michela Geri, a graduate student in MIT's Department of Mechanical Engineering and the study's lead author. "If you have a fundamental understanding, you can start designing things the way you want them to work."

Geri's co-authors are Bavand Keshavarz, a lecturer in mechanical engineering, John Bush, professor of applied mathematics in MIT's Department of Mathematics, and Gareth McKinley, the School of Engineering Professor of Teaching Innovation.

An uplifting experiment

The team's results grew out of a question that Bush posed in his graduate course 18.357 (Interfacial Phenomena): Why should a temperature difference play a role in a droplet's coalescence, or mixing?

Geri, who was taking the course at the time, took on the challenge, first by carrying out a series of experiments in McKinley's lab.

She built a small box, about the size of an espresso cup, with acrylic walls and a metal floor, which she placed on a hot/cold plate. She filled the cube with a bath of silicone oil, and just above the surface of the bath she set a syringe through which she pumped droplets of silicone oil of the same viscosity. In each series of experiments, she set the temperature of the hot/cold plate, and measured the temperatures of the oil pumped through the syringe and at the surface of the bath.

Geri used a high-speed camera to record each droplet, at 2,000 frames per second, from the time it was released from the syringe to the time at which it mixed thoroughly with the bath. She performed this experiment using silicone oils with a range of viscosities, from water-like to 500 times thicker.

She found that droplets appeared to levitate on a bath's surface as the temperature gradient between the two fluids increased. She was able to levitate a droplet, delaying its coalescence, by as long as 10 seconds, by maintaining a temperature difference of up to 30 degrees Celsius, or 86 degrees Fahrenheit, comparable to the difference between a drop of cold milk on a bath of hot black coffee.

Geri plotted the data and observed that the droplet's residence time on the bath's surface seemed to depend on the initial temperature difference between the two fluids, raised to the power of two-thirds. She also noticed that there exists a critical temperature difference at which a droplet of a given viscosity will not mix but instead levitate on a liquid surface.

"We saw this relationship clearly in the lab and then tried to develop a theory in hopes of rationalizing that dependence," Geri says.

A cushion's character

The team first looked to characterize the layer of air separating the droplet from the bath. The researchers hypothesized that a temperature difference between the two fluids may influence this air cushion, which may in turn act to keep a droplet afloat.

To investigate this idea mathematically, the researchers performed a calculation, referred to in fluid mechanics as a lubrication analysis, in which they appropriately simplified the complex equations describing fluid motion, to describe the flow of air between the droplet and the bath.

Through these equations, they found that temperature differences between the fluid drop and the fluid bath create convection, or circulating currents in the intervening layer of air. The greater the temperature difference, the stronger the air currents, and the greater the pressure that pushes against the droplet's weight, preventing it from sinking and making contact with the bath.

"We found the force coming from the droplet's weight and the force coming from the recirculation of the air layer will balance at a point, and to get that balance, you need a minimum, or critical temperature difference, in order for the droplet to levitate," Geri says.

Inside a single drop

Next, the team looked for a mathematical explanation for why they observed the 2:3 relationship between the amount of time a droplet levitates on a liquid surface and the initial temperature difference between the two fluids.

"For that, we had to think about how the temperature of the drop changes over time and approaches the temperature of the bath," Geri says.

"With a temperature difference, you generate a flow inside the drop, drawing up heat from the bath, which circulates around until the droplet temperature is the same as the bath and you don't levitate anymore," Bush adds. "We were able to describe that process mathematically."

To do so, the researchers adapted another set of equations, which describe the mixing of two fluids. They used the equations to model a warm parcel of liquid within the droplet that has been warmed by the bath below. They were able to characterize how that parcel of liquid mixed with the colder portions of the droplet, warming the entire droplet over time.

Through this modeling, they could observe how the temperature difference between fluids decreased over time, to the point at which a droplet stopped levitating and ultimately mixed with the rest of the bath.

"If you study that process mathematically, you can show the way in which temperature is changing in the droplet over time is exactly with this power law of 2/3 that we observed in our experiments," Geri says.

Bush says that their results can be used to characterize the spread of certain chemical and biological agents that are transferred through raindrops and sprays.

Read more at Science Daily

New treasures from Tutankhamun’s tomb

Embossed gold application with motif of animal combat of Levantine origin.
As part of a German-Egyptian project, archaeologists from Tübingen for the first time examine embossed gold applications from the sensational find of 1922. The motifs indicate surprising links between the Levant and the Egypt of the pharaohs.

Researchers from Tübingen working on a German-Egyptian project have examined embossed gold applications from the treasure of the tomb of the pharaoh Tutankhamun for the first time. The objects come from the famed find made by English archaeologist Howard Carter in 1922. Until now, they had been held in storage at the Egyptian Museum Cairo. They can be seen at a special exhibition at the museum which began on Wednesday. Conservators and archaeologists of the Institute of Ancient Near Eastern Studies (IANES, Professor Peter Pfälzner), the German Archaeological Institute, Cairo, (DAI, Professor Stephan Seidlmayer), and the Römisch-Germanischen Zentralmuseums Mainz (RGZM, Professor Falko Daim), as well as the Egyptian Museum have spent four years (2013-2017) analysing the find.

Through painstaking hours in the lab, the partners restored the objects at the Egyptian Museum. They also made drawings of the items and did comprehensive research on them. A team of conservators, Egyptologists and specialists in Near Eastern archaeology found the embossed gold applications in the same crate they were placed in by Howard Carter's team immediately after their discovery. At the time, the artefacts were photographed and packed, unrestored, and were never again removed until this project.

During years of detail work, conservators Christian Eckmann and Katja Broschat of the Römisch-Germanischen Zentralmuseum Mainz reassembled the fragments to produce 100 nearly complete embossed gold applications. They suspect the items are decorative fittings for bow cases, quivers and bridles. IANES archaeologists from Tübingen examined the images on the embossed gold applications and categorized them from an art-historical perspective. In her dissertation, doctoral candidate Julia Bertsch succeeded in distinguishing the Egyptian motifs on the embossed gold applications from those that could be ascribed to an "international," Middle Eastern canon of motifs.

Among these are images of fighting animals and goats at the tree of life that are foreign to Egyptian art and must have come to Egypt from the Levant. "Presumably these motifs, which were once developed in Mesopotamia, made their way to the Mediterranean region and Egypt via Syria," explains Peter Pfälzner. "This again shows the great role that ancient Syria played in the dissemination of culture during the Bronze Age."

Interestingly, he adds, similar embossed gold applications with thematically comparable images were found in a tomb in the Syrian Royal city of Qatna. There, the team of archaeologists from Tübingen led by Pfälzner, discovered a pristine king's grave in 2002. It dates back to the time of around 1340 B.C., so it is just a bit older than Tutankhamun's tomb in Egypt. The archaeologist says, "This remarkable aspect provided the impetus for our project on the Egyptian finds." Now," says Pfälzner, "we need to solve the riddle of how the foreign motifs on the embossed gold applications came to be adopted in Egypt." The professor says that here, chemical analyses have been illuminating. "The results showed that the embossed gold applications with Egyptian motifs and the others with foreign motifs were made of gold of differing compositions," he says. "That does not necessarily mean the pieces were imported. It may be that various local workshops were responsible for producing objects in various styles -- and that one used Near Eastern models."

Read more at Science Daily

Archaeology: Medieval treasure unearthed at the Abbey of Cluny

(1) Knotted tanned hide bundle before extraction of contents; (2) & (4) gold dinars; (3) signet ring with intaglio; (5) contents of knotted tanned hide bundle.
In mid-September, a large treasure was unearthed during a dig at the Abbey of Cluny, in the French department of Saône-et-Loire: 2,200 silver deniers and oboles, 21 Islamic gold dinars, a signet ring,1 and other objects made of gold. Never before has such a large cache of silver deniers been discovered. Nor have gold coins from Arab lands, silver deniers, and a signet ring ever been found hoarded together within a single, enclosed complex.

Anne Baud, an academic at the Université Lumière Lyon 2, and Anne Flammin, a CNRS engineer -- both from the Laboratoire Archéologie et Archéométrie (CNRS / Université Lumière Lyon 2 / Claude Bernard Lyon 1 University) -- led the archaeological investigation, in collaboration with a team of 9 students from the Université Lumière Lyon 2 and researchers from the Maison de l'Orient et de la Méditerranée Jean Pouilloux (CNRS / Université Lumière Lyon 2).

The excavation campaign, authorized by the Bourgogne-Franche-Comté Regional Department of Cultural Affairs (DRAC), began in mid-September and ended in late October. It is part of a vast research program focused on the Abbey of Cluny. Students in the Master of Archaeology and Archaeological Science program at the Université Lumière Lyon 2 have been participating in archaeological digs at the Abbey of Cluny since 2015. This experience in the field complements their academic training and gives them an insight into professional archaeology.

At the site, the team led by Anne Baud et Anne Flammin, including the students from the Université Lumière Lyon 2, discovered a treasure consisting of

§ more than 2,200 silver deniers and oboles -- mostly minted by the Abbey of Cluny and probably dating to the first half of the 12th century -- in a cloth bag, traces of which remain on some of the coins

§ a tanned hide bundle, found among the silver coins, fastened with a knot, and enclosing

o 21 Islamic gold dinars struck between 1121 and 1131 in Spain and Morocco, under the reign of Ali ibn Yusuf (1106-1143), who belonged to the Berber Almoravid dynasty.

o a gold signet ring with a red intaglio depicting the bust of a god and an inscription possibly dating the ring back to the first half of the 12th century

o a folded sheet of gold foil weighing 24 g and stored in a case

o a small circular object made of gold

Vincent Borrel, a PhD student at the Archaeology and Philology of East and West (CNRS / ENS) research unit -- AOROC for short -- is currently studying the treasure in more detail to identify and date the various pieces with greater precision.

A precious find . . .

This is an exceptional find for a monastic setting and especially that of Cluny, which was one of the largest abbeys of Western Europe during the Middle Ages. The treasure was buried in fill where it seems to have stayed for 850 years.

It includes items of remarkable value: 21 gold dinars and a signet ring, a very expensive piece of jewelry that few could own during the Middle Ages. At that time, Western currency was mostly dominated by the silver denier. Gold coins were reserved for rare transactions. The 2,200 or so silver deniers, struck at Cluny or nearby, would have been for everyday purchases. This is the largest stash of such coins ever found.

The fact that Arab currency, silver deniers, and a signet ring were enclosed together makes this discovery all the more interesting.

. . . opening new avenues of research into the history of the Abbey of Cluny

This discovery will breathe new life into research delving into the past of the abbey, a historic site open to the public and managed by the Centre des Monuments Nationaux (CMN). It also raises new questions worth answering:

ð Who owned the treasure? Was it a monk, a church dignitary, or a rich layman?

ð What can the coins teach us? Where were the silver deniers of Cluny struck? Where did they circulate? How did Islamic dinars minted in Spain and Morocco end up at Cluny?

Read more at Science Daily

Pluto's hydrocarbon haze keeps dwarf planet colder than expected

Pluto's haze layer is blue in this image taken by the New Horizons Ralph/Multispectral Visible Imaging Camera and computer generated to replicate true color. Haze is produced by sunlight-initiated chemical reactions of nitrogen and methane, leading to small particles that grow and settle toward the surface.
The gas composition of a planet's atmosphere generally determines how much heat gets trapped in the atmosphere. For the dwarf planet Pluto, however, the predicted temperature based on the composition of its atmosphere was much higher than actual measurements taken by NASA's New Horizons spacecraft in 2015.

A new study published November 16 in Nature proposes a novel cooling mechanism controlled by haze particles to account for Pluto's frigid atmosphere.

"It's been a mystery since we first got the temperature data from New Horizons," said first author Xi Zhang, assistant professor of Earth and planetary sciences at UC Santa Cruz. "Pluto is the first planetary body we know of where the atmospheric energy budget is dominated by solid-phase haze particles instead of by gases."

The cooling mechanism involves the absorption of heat by the haze particles, which then emit infrared radiation, cooling the atmosphere by radiating energy into space. The result is an atmospheric temperature of about 70 Kelvin (minus 203 degrees Celsius, or minus 333 degrees Fahrenheit), instead of the predicted 100 Kelvin (minus 173 Celsius, or minus 280 degrees Fahrenheit).

According to Zhang, the excess infrared radiation from haze particles in Pluto's atmosphere should be detectable by the James Webb Space Telescope, allowing confirmation of his team's hypothesis after the telescope's planned launch in 2019.

Extensive layers of atmospheric haze can be seen in images of Pluto taken by New Horizons. The haze results from chemical reactions in the upper atmosphere, where ultraviolet radiation from the sun ionizes nitrogen and methane, which react to form tiny hydrocarbon particles tens of nanometers in diameter. As these tiny particles sink down through the atmosphere, they stick together to form aggregates that grow larger as they descend, eventually settling onto the surface.

"We believe these hydrocarbon particles are related to the reddish and brownish stuff seen in images of Pluto's surface," Zhang said.

The researchers are interested in studying the effects of haze particles on the atmospheric energy balance of other planetary bodies, such as Neptune's moon Triton and Saturn's moon Titan. Their findings may also be relevant to investigations of exoplanets with hazy atmospheres.

Read more at Science Daily

Archaeological Treasures in Iraq Unearthed Just Before Deadly 7.3 Earthquake

Neo-Assyrian cylinder seal and imprint on right, height 1.5 inches. It depicts two winged genies on a sacred tree.
Iraq is the birthplace of numerous historic firsts. It is where the sailboat, wheel, and seed plow were invented. Lying within the Fertile Crescent, it is where cereal agriculture and commercial record keeping began. Even the concept of zero and 360-degree circles were formulated in what is now Iraq.

Iraq and nearby Iran’s history are therefore of great interest to archaeologists, who often must face both manmade and natural challenges when working in the region. Earthquakes, such as the 7.3 magnitude on that struck Iran and Iraq on November 12, threaten not only people, but also invaluable archaeological artifacts that are important to the collective history of humankind.

A recent six-week excavation in the province fortuitously ended before the earthquake struck. The work focused on the 7.4-acre site Gird-î Qalrakh on the Shahrizor Plain, and unearthed evidence for an ancient, centuries-old textile industry in a region now famed for its colorful Iraqi-Kurdish carpets and related woven goods.

The discoveries almost didn't happen.

Project leader Dirk Wicke of the Institute of Archaeology at Goethe University and his team were wrapping up their excavation, when student Lanah Haddad noticed a wall from a mysterious room within the trench where she was digging. Wicke asked her to keep removing dirt. As she did, several clay weights became visible, along with the charred remains of a large ancient loom.

“Lanah worked hard with the support of 1–2 students, and I decided to leave her trench alone and open for 2 more days — which was really worth it,” Wicke told Seeker.

Backfilling of trenches following excavation
His curiosity grew over other clay objects in the trench, due to their slightly off color and texture. Similar moments have happened to him before, he said, explaining that when he sees such clues, he will try to turn the clay objects over, in order to identify possible lines, dots, and curves, which form a pattern or shape.

“Once carefully dry-cleaned in the dig house, you start to twist the find beneath strong light from all sides in order to identify the images,” he said. “In this case, they were beautiful Sasanian griffins and horses.”

Griffins — mythical creatures with the head and wings of an eagle and the body of a lion — are perhaps best known to people today from the popular Harry Potter films.

Although the lighting was poor in the tiny, cramped dig house where he and his team were based during the excavation, they were able to photograph the griffin. His team determined that the object and others found with it were probably seals from rolls of fabric.

Seal impression of griffin, c. 2cm
About 16 and a half feet below the layer where the loom and seals were discovered, the researchers found an elaborate cylinder seal dating to a much earlier time, the 9th-7th century BC Assyrian period. Assyria refers to a major Mesopotamian kingdom that, at its peak, stretched from Cyprus and the East Mediterranean to Iran, and from what is now Armenia and Azerbaijan in the Caucasus, to the Arabian Peninsula, Egypt, and eastern Libya.

The scientists were able to take a clear photo of the Assyrian cylinder seal.

"The seal was used as in modern administrative procedures — to function like a signature and authorize a treaty, letter, or other official document,” Wicke said. “One has to bear in mind, that the Assyrian documents were written in cuneiform script on wet, clay tablets, which later dried or got baked to last."

The cylinder seal depicts two winged genies with a purifying "cone" and a bucket of purifying liquid that was most likely water. The genies, he said, "flank a sacred tree expressing purification," which is "a standard topic in neo-Assyrian art."

"It is difficult to pinpoint an exact meaning to it, but this image was very often depicted in the royal palaces and appears to act as a beneficiary motif used to magically protect the king and inhabitants of the palace or palaces," he said.

On the back of this seal, opposite the tree, is a spade associated with the Babylonian god Marduk. This suggests that the seal was made and used when there were strong connections between Assyria and Babylonia, which was another ancient empire at the time.

Also dating to the 9th-7th century BC is a terraced, stone wall. The archaeologists believe it was part of a watchtower.

Wicke said that the land at the site was, and still is, "very fertile," making it an attractive location for settlement. Additionally, springs upstream of the site provide a near-continuous supply of fresh water, even during the hot and arid summer months.

It is little wonder then that people thrived on the Shahrizor plain during the much later era of the loom, which to an untrained eye looks a bit like a skeleton stretched out in a grave. The pieces instead are what is left of the large standing device that featured vertical hanging threads, which were pulled vertically straight by the clay loom weights. The threads were then woven horizontally.

"This is one of the oldest arrangements of a loom," Wicke said.

Excavated corner of room with remnants of the loom between the wall (top) and a bench of six mud bricks. The round loom weights made from clay are visible, as are slabs of mud once forming some kind of shelving.
Wicke suspected that for many centuries prior to around 4 AD it was home to a small farming community, but now they are rethinking its significance.

"It looks as if the site was taking part in a larger, overarching network of the textile trade, but this, of course, needs further examination," he said. "Why it was burnt, I really can't say."

The loom and seals came as a surprise to the researchers, who are studying the region's ceramic history that currently "still lacks a coherent pattern chronology," Wicke said. This work has been funded since 2015 by the local antiquities cervice, the Thyssen Foundation, and the Enki e.V. Association located at Goethe.

Read more at Seeker

Nov 15, 2017

Why hot water freezes faster than cold water

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A team of researchers from Universidad Carlos III de Madrid, the Universidad de Extremadura and the Universidad de Sevilla have defined a theoretical framework that could explain the Mpemba effect, a counterintuitive physical phenomenon revealed when hot water freezes faster than cold water.

The researchers, who have recently published the findings in Physical Review Letters, have confirmed how this phenomenon occurs in granular fluids, that is, those composed of particles that are very small and interact among those that lose part of their kinetic energy. Thanks to this theoretical characterization, "we can simulate on a computer and make analytical calculations to know how and when the Mpemba effect will occur," said Antonio Lasanta. Lasanta is from the UC3M Gregorio Millán Barbany University Institute for Modeling and Simulation on Fluid Dynamics, Nanoscience and Industrial Mathematics. "In fact," he said, "we find not only that the hottest can cool faster but also the opposite effect: the coldest can heat faster, which would be called the inverse Mpemba effect."

The fact that preheated liquids freeze faster than those that are already cold was observed for the first time by Aristotle in the 4th century AD. Francis Bacon, the father of scientific empiricism, and René Descartes, the French philosopher, were also interested in the phenomenon, which became a theory when, in 1960, a Tanzanian student named Erasto Mpemba explained to his teacher in a class that the hottest mixture of ice cream froze faster than the cold one. This anecdote inspired a technical document about the subject, and the effect began to be analyzed in educational and science magazines. However, its causes and effects have hardly been studied until now.

"It is an effect that, historically, has not been addressed in a rigorous manner but merely as an anomaly and a didactic curiosity," said Antonio Prados, one of the researchers from the Universidad de Sevilla Department of Theoretical Physics. "From our perspective, it was important to study it in a system with the minimum ingredients to be able to control and understand its behavior," he said. This has enabled them to understand what scenarios it is easier to occur in, which is one of the main contributions of this scientific study. "Thanks to this, we have identified some of the ingredients so that the effect occurs in some physical systems that we can describe well theoretically," stated researcher Francisco Vega Reyes and Andrés Santos, from the Universidad de Extremadura Instituto de Computación Científica Avanzada (Institute of Advanced Scientific Computation).

"The scenario that the effect will most easily occur in is when the velocities of the particles before heating or cooling have a specific disposition -- for example, with a high dispersion around the mean value," he said. This way, the evolution of the temperature of the fluid can be significantly affected if the state of the particles is prepared before the cooling.

Read more at Science Daily