The headache of adapting to the cold, literally

Frequency of the adaptive allele in several human populations (from the 1000 Genomes dataset).

A common genetic variant implicated in migraine headaches may have proliferated because it helped early humans adapt to cold weather in northern climates. Felix Key of the Max Planck Institute for Evolutionary Anthropology and colleagues report these findings in a new study published May 3rd, 2018 in PLOS Genetics.

Within the last 50,000 years, some humans left the warm climate of Africa to colonize colder locales in Asia, Europe, and other parts of the world. "This colonization could have been accompanied by genetic adaptations that helped early humans respond to cold temperatures" says Aida Andres, who supervised the study. To find evidence of this adaptation, researchers took a closer look at TRPM8, a gene that codes for the only known receptor that enables a person to detect and respond to cool and cold temperatures. They discovered that a genetic variant upstream from the gene, which may regulate it, became increasingly common in populations living in higher latitudes during the last 25,000 years. Only 5% of people with Nigerian ancestry carry the variant, compared to 88% of people with Finnish ancestry. Currently, the percentage of people in a population that carry the variant increases at higher latitudes and with colder climates. Interestingly, scientists had already identified this variant as being strongly associated with migraine headaches.

Migraine is a debilitating neurological disorder that affects millions worldwide. The percentage of people who suffer from the disorder varies across human populations, but is highest in individuals of European descent, which is also the population with the highest frequency of the cold-adaptive variant. The researchers suspect that adaptation to cold temperatures in early human populations may have contributed, to some extent, to the variation in migraine prevalence that exists among human groups today. Felix Key pointed out that "this study nicely shows how past evolutionary pressures can influence present-day phenotypes."

From Science Daily

Revealing the remarkable nanostructure of human bone

Interweaving mineral and protein form continuous networks to provide the strength essential for functional bones.

Scientists have produced a 3D nanoscale reconstruction of the mineral structure of bone.

Bone performs equally well whether in an accelerating cheetah or in a heavy elephant, thanks to its toughness and strength.

The properties of bone can be attributed to its hierarchical organisation, where small elements form larger structures.

However, the nanoscale organisation and relationship between bone's principle components -- mineral and protein -- have not been fully understood.

Using advanced 3D nanoscale imaging of the mineral in human bone, research teams from the University of York and Imperial College London have shown that the mineral crystals of bone have a hierarchical structure integrated into the larger-scale make-up of the skeleton.

Researchers combined a number of advanced electron microscopy-based techniques, and found that the principal building blocks of mineral at the nanometre scale are curved needle-shaped nanocrystals that form larger twisted platelets that resemble propeller blades.

The blades continuously merge and split throughout the protein phase of bone. The interweaving mineral and protein form continuous networks to provide the strength essential for functional bones.

Lead author, Associate Professor Roland Kröger, from the University of York's Department of Physics, said: "Bone is an intriguing composite of essentially two materials, the flexible protein collagen and the hard mineral called apatite."

"There is a lot of discussion about the way these two stiff and flexible phases uniquely combine to provide toughness and strength to bone.

"The combination of the two materials in a hierarchical manner provides bone with mechanical properties that are superior to those of its individual components alone and we find that there are 12 levels of hierarchy in bone."

Dr Natalie Reznikov, formerly of Imperial College, London and an author on the paper, said: "If we compare this arrangement, for example, to an individual living in a room of a house, this extends to a house in a street, then the street in a neighbourhood, a neighbourhood in a city, a country and on it goes. If you continue to 12 levels you are reaching the size of a galaxy! "

Professor Molly Stevens, from Imperial College, London, added: "This work builds on the shoulders of many beautiful previous studies investigating the fundamental properties and structure of bone and helps to unlock an important missing piece of the puzzle."

Besides the large number of nested structures in bone, a common feature of all of them is a slight curvature, providing twisted geometry. To name a few, the mineral crystals are curved, the protein strands (collagen) are braided, the mineralized collagen fibrils twist, and the entire bones themselves have a twist, such as those seen in the curving shape of a rib for example.

Fractals are common in Nature: you can see self-similar patterns in lightning bolts, coast lines, tree branches, clouds and snowflakes. This means that the structure of bone follows a fundamental order principle in Nature.

Read more at Science Daily

Cracking open the formation of fossil concretions

Gigantic concretions formed in mudstone on New Zealand's Moeraki coast; about 50 million years old. The present research shows that even concretions of this size formed very rapidly, within several decades.

All over the world, spectacular fossils have frequently been found preserved inside solid, roughly spherical rocks called "concretions." From geologists to casual observers, many have wondered why these hardened masses of carbonate formed around dead organisms, with round shapes and sharp boundaries with the surrounding material, typically in marine mud and mudstone.

Several important questions regarding concretions have long puzzled scientists. What conditions cause them to form? How long do they take to grow? Why do they stop growing? Why are they so distinct from the surrounding rock or sediments?

Now, researchers led by Nagoya University have developed a method to analyze concretions using L-shaped "cross-plot diagrams" of diffusion and growth rate, reported in a new study published in Scientific Reports. With this method, they analyzed dozens of concretions from three sites across Japan and compared them with concretions from England and New Zealand.

The results of this new study dramatically impact understanding of the rate at which concretions form. "Until now, the formation of spherical carbonate concretions was thought to take hundreds of thousands to millions of years," co-author Koshi Yamamoto says. "However, our results show that concretions grow at a very fast rate over several months to several years." This rapid sealing mechanism could explain why some concretions contain well-preserved fossils of soft tissues that are rarely fossilized under other conditions.

Study first author Hidekazu Yoshida explains, "The concretions maintained their characteristics, with well-preserved fossils at their centers or textures indicative of the original presence of organic matter. Simple mass balance calculations also demonstrate that the carbon fixed in the carbonate concretions came predominantly from the organs of organisms inside the concretions."

All of the studied concretions were composed of calcite, with relatively consistent compositions throughout, distinct from the surrounding muddy matrix. Fine-grained, generally clay-rich sediments were found to be important to limit diffusion and permeability, and to slow the migration of solutes. Thus, bicarbonate concentrations would rise high enough at a reaction front to cause rapid precipitation of calcium carbonate, with sharp boundaries from the surrounding mud.

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First-in-world robot-assisted spinal surgery

Noah Pernikoff is back to his life in New York City after becoming the first patient in the world to undergo a complex three-part, robotic-assisted surgery. The robotic arms made it possible for the multidisciplinary team at Penn to successfully remove a rare tumor from Noah's neck, where the skull meets the spine. The ground breaking surgery was completed by a multi-surgeon team, led by Dr. Neil Malhotra, at the Hospital of the University of Pennsylvania in August 2017 over a span of two days and more than 20 hours.

Chordoma is a rare type of cancer that occurs in the bones of the skull base and spine. A chordoma tumor usually grows slowly and is often asymptomatic for years. In the case of 27-year-old Noah Pernikoff, a 2016 car accident revealed his surprising diagnosis.

Among his injuries from the accident, Noah -- who was working in New York City for a commercial contracting firm -- tore his rotator cuff and had several herniated discs. More important, however, was his post-accident nagging neck pain, which lead to an x-ray that revealed a concerning lesion in his neck, on his cervical spine. The lesion was clearly unrelated to the accident, and far more concerning than the minor injuries he had endured. After making a recovery from the accident, Pernikoff's father, a physician, encouraged his son to see a neurosurgeon for evaluation of the injury. The neurosurgeon Pernikoff saw ultimately recommended a biopsy of the spot, which resulted in a diagnosis of chordoma.

"I'm lucky because they caught mine early. For a lot of people, if it's not found and treated early, it's lethal," Pernikoff said. "The doctor said if I hadn't discovered it through the car accident it probably would have kept growing until it came to a point on my spinal cord where it caused paralysis or death. I feel very lucky in that regard." Unfortunately, the neurosurgeon explained to Pernikoff, while surgery is known to be the best option for chordoma, Pernikoff's would be too difficult to resect and he would have to try the second option, radiation with proton therapy.

Chordoma is extremely rare; it affects only one in 1 million people each year. Pernikoff's specific type of chordoma, located on his C2 vertebrae, is even rarer, making treatment a challenge. Pernikoff's neurosurgeon immediately referred him to Penn, where a multidisciplinary team reviewed his case, and his options, and began crafting a treatment plan -- not through radiation, but a complex surgery that had never been performed before.

Neil Malhotra, MD, an assistant professor of Neurosurgery and Orthopaedic Surgery and the vice chair of operations in the department of Neurosurgery, gathered a multidisciplinary team of physicians to treat Pernikoff's chordoma. Malhotra planned to remove the tumor through a rare and complex spinal surgery approach. Bert W. O'Malley Jr., MD, a professor and chairman of the department of Otorhinolaryngology: Head and Neck Surgery, planned to aid Malhotra's approach and improve Pernikoff's recovery by using a trans-oral robotic (TORS) approach for the second part of the surgery. TORS is the world's first group of minimally invasive robotic surgery techniques, invented at Penn, to remove benign and malignant tumors of the mouth and throat.

"This would be a first ever use of a robot in this manner -- a rare approach to an already rare and complex case," Malhotra said. "Our team needed to reconstruct the removed area of Pernikoff's spine using bone and rods, and that was only the beginning."

The stakes were high. Because of the placement of the tumor, Malhotra said removal could compromise the structural integrity of Pernikoff's spine, causing permanent paralysis. There was also a risk of complications such as bone and tissue breakdown, loss of sense of smell, fine motor skill issues, and complete paralysis. And, he said, "if we couldn't remove the entire tumor, it would likely grow back, perhaps more aggressive than before."

The surgery was performed in three parts. First, the neurosurgeons went through the back of Pernikoff's neck and cut the spine around the tumor to prepare for the second stage, removing the tumor through his mouth. The key to this stage would be to make ultrasonic bone cuts -- removing a piece of bone -- around the tumor without touching it, and without injuring the spinal cord that lay between the neurosurgeon and the tumor/spinal column. With stage one success, O'Malley and a team of three head and neck surgeons used the surgical robot to clear a path so Malhotra could remove the tumor, and part of the spinal column, in its entirety through the mouth. Finally, the team reconstructed Pernikoff's spinal column, which was now missing an important bone in his neck, using some of Pernikoffs' own bone from his hip and rods to finalize stabilization of the newly built portion of his spine.

Read more at Science Daily

Gray hair linked to immune system activity and viral infection

Researchers at UAB and NIH report that loss of hair pigmentation, or gray hair, is associated with innate immune activation in mouse.

A new study on mice offers insights into why some people's hair may turn gray in response to a serious illness or chronic stress. Publishing May 3 in the open access journal PLOS Biology, researchers at the National Institutes of Health and the University of Alabama, Birmingham have discovered a connection between the genes that contribute to hair color and the genes that notify our bodies of a pathogenic infection.

When a body is under attack from a virus or bacteria, the innate immune system kicks into gear. All cells have the ability to detect foreign invaders and they respond by producing signaling molecules called interferons. Interferons signal to other cells to take action by turning on the expression of genes that inhibit viral replication, activate immune effector cells, and increase host defenses.

The connection between hair pigmentation and innate immune regulation was initially a bit surprising. Melissa Harris, primary author and assistant professor within the Department of Biology at UAB explains, "Genomic tools allow us to assess how all of the genes within our genome change their expression under different conditions, and sometimes they change in ways that we don't anticipate. We are interested in genes that affect how our stem cells are maintained over time. We like to study gray hair because it's an easy read-out of melanocyte stem cell dysfunction." Melanocyte stem cells are essential to hair color as they produce the melanocytes that are responsible for making and depositing pigment into the hair shaft.

In this case, an unexpected link was found between gray hair, the transcription factor MITF, and innate immunity. MITF is best known for its role in regulating the many functions within melanocytes. But the researchers found that MITF also serves to keep the melanocytes' interferon response in check. If MITF's control of the interferon response is lost in melanocyte stem cells, hair-graying results. Furthermore, if innate immune signaling is artificially activated in mice that are predisposed for getting gray hair, increased numbers of gray hairs are also produced.

"This new discovery suggests that genes that control pigment in hair and skin also work to control the innate immune system," said William Pavan, study co-author and chief of the Genetic Disease Research Branch at NIH's National Human Genome Research Institute (NHGRI). "These results may enhance our understanding of hair graying. More importantly, discovering this connection will help us understand pigmentation diseases with innate immune system involvement like vitiligo." Vitiligo, which causes discolored skin patches, affects between 0.5 percent to 1 percent of all humans.

Read more at Science Daily

Researchers defy biology: Mice remain slim on burger diet

Mouse eating cheese.

We are our own worst enemy when it comes to developing obesity. The body is naturally geared to assimilate energy from the food we eat and store it as fat until it is needed. This is the result of millions of years of evolution under the pressure of low food availability.

But today, where many of us have constant access to high calorie foods, our body's impressive ability to convert food into fat has, ironically, become problematic. Consequently, the number of overweight people worldwide is skyrocketing, leading to large health consequences for both the individual and society.

However, as part of a new study, researchers at the University of Copenhagen have now managed to inhibit the body's ability to store fat. They genetically delete the enzyme NAMPT in fat tissue of mice, and this renders the animals completely resistant to becoming overweight or obese, even on a very fatty diet.

'We gave the mice a diet that more or less corresponds to continuously eating burgers and pizza. Still, it was impossible for them to expand their fat tissue. Our ultimate goal is that by understanding these fundamental underpinnings of how we become obese, we can apply our finding to the development of novel treatment strategies for metabolic disease,' says Karen Nørgaard Nielsen, first author on the publication and a Ph.D. student at the Novo Nordisk Foundation Center for Basic Metabolic Research.

High-Fat Food, Same Weight

The findings are in line with results obtained from humans. Several studies have shown that the presence of large amounts of the enzyme NAMPT in blood and in stomach fat tissue is significantly connected with being overweight or obese. However, this study provides the first evidence that NAMPT is absolutely required to become overweight or obese and that lack of NAMPT in fat tissue fully protects against obesity.

In the University of Copenhagen study, the researchers compared how normal mice and mice lacking NAMPT in fat tissue gained weight when given either high-fat food or a healthier, lower-fat diet. When on the healthy diet, there was no difference in body weight or the amount of fat between the normal mice and the mice lacking NAMPT.

However, when the mice were given high-fat food, the control mice became very obese, yet the mice lacking NAMPT gained no more weight from high-fat food than when they were on the healthier diet. In addition, the mice lacking NAMPT maintained better control of blood glucose than normal mice when eating high-fat food.

Contradicts the General View

The result challenges the general view of NAMPT, which is largely seen as an enzyme that should be boosted for therapeutic purposes.

'NAMPT appears to increase the metabolic functionality of almost every tissue in the body in which it has been studied. For example, there are indications that the liver and skeletal muscle may benefit from increased NAMPT activity. We similarly find that NAMPT is critical for fat tissue function. Unfortunately, that function is efficiently storing fat. NAMPT in fat tissue was likely once an extraordinary benefit to our ancestors but in today's society full of high-fat, calorically-dense foods, it may now pose a liability', says Associate Professor Zachary Gerhart-Hines from the Novo Nordisk Foundation Center for Basic Metabolic Research and corresponding author on the study.

He does not necessarily believe that generally decreasing NAMPT is a viable treatment strategy in humans. There would be too great a risk for potentially harmful consequences in other tissues of the body.

Read more at Science Daily

What the gorilla microbiome tells us about evolution and human health

A study of the microbiomes of wild gorillas and chimpanzees offers insights into the evolution of the human microbiome and might even have implications for human health. The research project was led by scientists at the Center for Infection and Immunity (CII) at Columbia University's Mailman School of Public Health. Findings appear in the journal Nature Communications.

The researchers used genetic sequencing to analyze fecal samples collected by the Wildlife Conservation Society (WCS) from wild African great apes living the Sangha region of the Republic of Congo over the course of three years. Their goal was to understand the mix of gut microbes living in gorillas and chimpanzees and compare them to those already documented in other non-human primates and human populations. They found that gorilla and chimpanzee microbiomes fluctuate with seasonal rainfall patterns and diet, switching markedly during the summer dry period when succulent fruits abound in their environment and make up a larger proportion of their diet, as opposed to their usual, more fiber-rich diet of leaves and bark.

These seasonal shifts in the microbiomes of gorillas and chimpanzees are similar to seasonal microbiome changes observed in the human Hadza hunter-gatherers from Tanzania, who also rely heavily on the seasonal availability of foods in their environment. Seasonal shifts in the microbiomes of human industrialized cultures, such as the United States, are likely less prevalent owing to reduced reliance on seasonally available foods and globalization of the food supply, as evident in any grocery store.

"While our human genomes share a great deal of similarity with those of our closest living relatives, our second genome (the microbiome) has some important distinctions, including reduced diversity and the absence of bacteria and archaea that appear to be important for fiber fermentation," says first author Allison L. Hicks, MS, a researcher at CII. "Understanding how these lost microbes influence health and disease will be an important area for future studies."

"We observed dramatic changes in the gorilla and chimpanzee microbiomes depending on seasons and what they are eating," says senior author Brent L. Williams, PhD, assistant professor of Epidemiology at CII. "Bacteria that help gorillas break down fibrous plants are replaced once a year by another group of bacteria that feed on the mucous layer in their gut during the months they are eating fruits.

"The fact that our microbiomes are so different from our nearest living evolutionary relatives says something about how much we've changed our diets, consuming more protein and animal fat at the expense of fiber," says Williams. "Many humans may be living in a constant state of fiber deficiency. Such a state may be promoting the growth of bacteria that degrade our protective mucous layer, which may have implications for intestinal inflammation, even colon cancer."

All great apes are endangered or critically endangered. Down to fewer than 500,000, their numbers have been reduced through deforestation-which destroys their habitat-and through hunting, including for meat. Even infectious disease is a major factor-as many as one-quarter of the world's gorilla population has died because of Ebola.

"We are losing biodiversity on a global scale," cautions co-author Sarah Olson, PhD, associate director of wildlife health at WCS. "In fact, our own human microbiome is not immune to this phenomenon. There is an ever growing need for conservation efforts to preserve environments that are vital to the health of animal populations."

Read more at Science Daily

Flares in the universe can now be studied on Earth

Solar flares are caused by magnetic reconnection in space and can interfere with our communications satellites, affecting power grids, air traffic and telephony. Now, researchers at Chalmers University of Technology, Sweden, have found a new way to imitate and study these spectacular space plasma phenomena in a laboratory environment.

Solar flares, cosmic radiation, and the northern lights are well known phenomena. But exactly how their enormous energy arises is not as well understood.

Now, physicists at Chalmers University of Technology, Sweden, have discovered a new way to study these spectacular space plasma phenomena in a laboratory environment. The results have been published in the journal Nature Communications.

"Scientists have been trying to bring these space phenomena down to earth for a decade. With our new method we can enter a new era, and investigate what was previously impossible to study. It will tell us more about how these events occur," says Longqing Yi, researcher at the Department of Physics at Chalmers.

The research concerns so-called 'magnetic reconnection' -- the process which gives rise to these phenomena. Magnetic reconnection causes sudden conversion of energy stored in the magnetic field into heat and kinetic energy. This happens when two plasmas with anti-parallel magnetic fields are pushed together, and the magnetic field lines converge and reconnect. This interaction leads to violently accelerated plasma particles that can sometimes be seen with the naked eye -- for example, during the northern lights.

Magnetic reconnection in space can also influence us on earth. The creation of solar flares can interfere with communications satellites, and thus affect power grids, air traffic and telephony.

In order to imitate and study these spectacular space plasma phenomena in the laboratory, you need a high-power laser, to create magnetic fields around a million times stronger than those found on the surface of the sun. In the new scientific article, Longqing Yi, along with Professor Tünde Fülöp from the Department of Physics, proposed an experiment in which magnetic reconnection can be studied in a new, more precise way. Through the use of grazing incidence of ultra-short laser pulses, the effect can be achieved without overheating the plasma. The process can thus be studied very cleanly, without the laser directly affecting the internal energy of the plasma.

The proposed experiment would therefore allow us to seek answers to some of the most fundamental questions in astrophysics.

"We hope that this can inspire many research groups to use our results. This is a great opportunity to look for knowledge that could be useful in a number of areas. For example, we need to better understand solar flares, which can interfere with important communication systems. We also need to be able to control the instabilities caused by magnetic reconnection in fusion devices," says Tünde Fülöp.

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Frequent sauna bathing reduces risk of stroke

Frequent sauna bathing reduces the risk of stroke.

Frequent sauna bathing is associated with a reduced risk of stroke, according to a new international study. In a 15-year follow-up study, people taking a sauna 4-7 times a week were 61% less likely to suffer a stroke than those taking a sauna once a week. This is the first prospective large-scale study on this topic, and the findings were reported in Neurology.

Stroke is one of the leading causes of disability worldwide, placing a heavy human and economic burden on societies. The reduced risk associated with sauna bathing was found by a team of scientists from the Universities of Eastern Finland, Bristol, Leicester, Atlanta, Cambridge and Innsbruck.

The findings are based on the population-based Kuopio Ischaemic Heart Disease Risk Factor (KIHD) study and involved 1,628 men and women aged 53 to 74 years living in the eastern part of Finland. Based on their frequency of taking traditional Finnish sauna baths (relative humidity 10-20%), the study participants were divided into three groups: those taking a sauna once a week, those taking a sauna 2-3 times a week, and those taking a sauna 4-7 times a week.

The more frequently saunas were taken, the lower was the risk of stroke. Compared to people taking one sauna session per week, the risk was decreased by 14% among those with 2-3 sessions and 61% among those with 4-7 sessions. The association persisted even when taking into account conventional stroke risk factors, such as age, sex, diabetes, body mass index, blood lipids, alcohol consumption, physical activity and socio-economic status. The strength of association was similar in men and women.

Previous results from the KIHD study at the University of Eastern Finland have shown that frequent sauna bathing also significantly reduces the risk of cardiovascular and all-cause mortality. According to the researchers, mechanisms driving the association of sauna bathing with reduced stroke may include a reduction in blood pressure, stimulation of immune system, a positive impact on the autonomic nervous system, and an improved cardiovascular function. In a recent experimental study, the same group of scientists also showed that sauna bathing has acute effects on the stiffness of the arterial wall, hence influencing blood pressure and cardiac function parameters.

From Science Daily

Engraved Crimean stone artifact may demonstrate Neanderthal symbolism

The engraved flint flake from Kiik-Koba layer IV.

A flint flake from the Middle Paleolithic of Crimea was likely engraved symbolically by a skilled Neanderthal hand, according to a study published May 2, 2018 in the open-access journal PLOS ONE by Ana Majkic from the University of Bordeaux, France and colleagues. The authors developed a detailed framework for interpreting engravings on stone artifacts.

Engraved stone artifacts are important clues to the history of human culture and cognition. Incisions on the cortex (soft outer layer) of flint or chert flakes are known from Middle and Lower Paleolithic sites across Europe and the Middle East. However, it can be difficult to determine the action that created an incision: was it an accidental scrape or purposeful engraving? To address this issue, Majkic and colleagues created an interpretive framework that allows researchers to classify the structure and patterns of engraved cortexes and cross-check these attributes with a list of possible causal actions.

They tested this methodology with an engraved flake from the cave site of Kiik-Koba in Crimea. The many stone artifacts at the site are associated with Neanderthal remains and date to around 35,000 years ago. Following microscopic examination of the grooved lines on the flint cortex, the researchers concluded that the incisions represent deliberate engravings that would have required fine motor skills and attention to detail. These engravings appear to have been made with symbolic or communicative intent.

If this interpretation is correct, this engraved flake would join a growing list of signs that Neanderthals engaged in symbolic activities, along with evidence of intentional burial, personal ornaments, and other decorated objects. This has implications for the question of when and how many times this sort of cultural expression has evolved among hominin populations. The researchers hope to hone their framework further for use with artifacts of varying ages and cultural contexts.

From Science Daily

Recent work challenges view of early Mars, picturing a warm desert with occasional rain

The Grand Canyon (a) versus a Martian dendritic river system (b) (Arabia quadrangle; 12 degrees N, 43 degrees E). Slight morphologic differences between terrestrial and Martian comparisons may be attributed to the great differences in age. Scale bar is 60 km long.

The climate of early Mars is a subject of debate. While it has been thought that Mars had a warm and wet climate, like Earth, other researchers suggested early Mars might have been largely glaciated. A recent study by Ramses Ramirez from the Earth-Life Science Institute (Tokyo Institute of Technology, Japan) and Robert Craddock from the National Air and Space Museum's Center for Earth and Planetary Studies (Smithsonian Institution, USA) suggests that the early Martian surface may not have been dominated by ice, but instead it may have been modestly warm and prone to rain, with only small patches of ice.

While there is little debate about whether water previously existed on Mars, the debate regarding what the climate of Mars was like around 4 billion years ago has persisted for decades. Mars has a surprisingly diverse landscape, made up of valley networks, lake basins and possible ocean shorelines. These ancient fluvial features all provide clues that early Mars may have had a warm and wet climate, similar to Earth's.

However, this idea has challenges. First, the amount of solar energy entering the atmosphere at the time was considered to be too low to support a warm and wet climate. Secondly, recent climate studies have argued that Mars' ancient fluvial features can be accounted for with an icy climate, where widespread surfaces of ice promoted cooling by reflecting solar radiation. Occasional warming events would have triggered large amounts of ice-melt, and fluvial activity as a result. However, Ramses Ramirez (Earth-Life Science Institute, Japan) and Robert Craddock (Smithsonian Institution, USA) suggest that early Mars was probably warm and wet, and not so icy, after a careful geological and climatological analysis revealed little evidence of widespread glaciation.

Recently, the authors' study, published in Nature Geoscience, argues that volcanic activity on a relatively unglaciated planet could explain Mars' fluvial features. Volcanic eruptions releasing CO2, H2, and CH4 may have contributed to the greenhouse effect, which in turn may have promoted warming, precipitation (including rain), and the flow of water that carved out the valleys and fluvial features. However, this climate would not have been as warm and wet as Earth's, with precipitation rates of around 10 centimeters per year (or less), similar to Earth's semi-arid regions. This drier climate suggests that small amounts of ice deposits could have also existed, though these would have been thin, and liable to melt, contributing to the fluvial system.

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Scientists find the first bird beak, right under their noses

Fossil reconstruction and illustration of Ichthyornis dispar.

Researchers have pieced together the three-dimensional skull of an iconic, toothed bird that represents a pivotal moment in the transition from dinosaurs to modern-day birds.

Ichthyornis dispar holds a key position in the evolutionary trail that leads from dinosaurian species to today's avians. It lived nearly 100 million years ago in North America, looked something like a toothy seabird, and drew the attention of such famous naturalists as Yale's O.C. Marsh (who first named and described it) and Charles Darwin.

Yet despite the existence of partial specimens of Ichthyornis dispar, there has been no significant new skull material beyond the fragmentary remains first found in the 1870s. Now, a Yale-led team reports on new specimens with three-dimensional cranial remains -- including one example of a complete skull and two previously overlooked cranial elements that were part of the original specimen at Yale -- that reveal new details about one of the most striking transformations in evolutionary history.

"Right under our noses this whole time was an amazing, transitional bird," said Yale paleontologist Bhart-Anjan Bhullar, principal investigator of a study published in the journal Nature. "It has a modern-looking brain along with a remarkably dinosaurian jaw muscle configuration."

Perhaps most interesting of all, Bhullar said, is that Ichthyornis dispar shows us what the bird beak looked like as it first appeared in nature.

"The first beak was a horn-covered pincer tip at the end of the jaw," said Bhullar, who is an assistant professor and assistant curator in geology and geophysics. "The remainder of the jaw was filled with teeth. At its origin, the beak was a precision grasping mechanism that served as a surrogate hand as the hands transformed into wings."

The research team conducted its analysis using CT-scan technology, combined with specimens from the Yale Peabody Museum of Natural History; the Sternberg Museum of Natural History in Fort Hays, Kan.; the Alabama Museum of Natural History; the University of Kansas Biodiversity Institute; and the Black Hills Institute of Geological Research.

Co-lead authors of the new study are Daniel Field of the Milner Centre for Evolution at the University of Bath and Michael Hanson of Yale. Co-authors are David Burnham of the University of Kansas, Laura Wilson and Kristopher Super of Fort Hays State University, Dana Ehret of the Alabama Museum of Natural History, and Jun Ebersole of the McWane Science Center.

"The fossil record provides our only direct evidence of the evolutionary transformations that have given rise to modern forms," said Field. "This extraordinary new specimen reveals the surprisingly late retention of dinosaur-like features in the skull of Ichthyornis -- one of the closest-known relatives of modern birds from the Age of Reptiles."

The researchers said their findings offer new insight into how modern birds' skulls eventually formed. Along with its transitional beak, Ichthyornis dispar had a brain similar to modern birds but a temporal region of the skull that was strikingly like that of a dinosaur -- indicating that during the evolution of birds, the brain transformed first while the remainder of the skull remained more primitive and dinosaur-like.

"Ichthyornis would have looked very similar to today's seabirds, probably very much like a gull or tern," said Hanson. "The teeth probably would not have been visible unless the mouth was open but covered with some sort of lip-like, extra-oral tissue."

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Hubble detects helium in the atmosphere of an exoplanet for the first time

The exoplanet WASP-107b is a gas giant, orbiting a highly active K-type main sequence star. The star is about 200 light-years from Earth. Using spectroscopy, scientists were able to find helium in the escaping atmosphere of the planet -- the first detection of this element in the atmosphere of an exoplanet.

Astronomers using the NASA/ESA Hubble Space Telescope have detected helium in the atmosphere of the exoplanet WASP-107b. This is the first time this element has been detected in the atmosphere of a planet outside the Solar System. The discovery demonstrates the ability to use infrared spectra to study exoplanet extended atmospheres.

The international team of astronomers, led by Jessica Spake, a PhD student at the University of Exeter in the UK, used Hubble's Wide Field Camera 3 to discover helium in the atmosphere of the exoplanet WASP-107b This is the first detection of its kind.

Spake explains the importance of the discovery: "Helium is the second-most common element in the Universe after hydrogen. It is also one of the main constituents of the planets Jupiter and Saturn in our Solar System. However, up until now helium had not been detected on exoplanets -- despite searches for it."

The team made the detection by analysing the infrared spectrum of the atmosphere of WASP-107b. Previous detections of extended exoplanet atmospheres have been made by studying the spectrum at ultraviolet and optical wavelengths; this detection therefore demonstrates that exoplanet atmospheres can also be studied at longer wavelengths.

"The strong signal from helium we measured demonstrates a new technique to study upper layers of exoplanet atmospheres in a wider range of planets," says Spake "Current methods, which use ultraviolet light, are limited to the closest exoplanets. We know there is helium in the Earth's upper atmosphere and this new technique may help us to detect atmospheres around Earth-sized exoplanets -- which is very difficult with current technology."

WASP-107b is one of the lowest density planets known: While the planet is about the same size as Jupiter, it has only 12% of Jupiter's mass. The exoplanet is about 200 light-years from Earth and takes less than six days to orbit its host star.

The amount of helium detected in the atmosphere of WASP-107b is so large that its upper atmosphere must extend tens of thousands of kilometres out into space. This also makes it the first time that an extended atmosphere has been discovered at infrared wavelengths.

Since its atmosphere is so extended, the planet is losing a significant amount of its atmospheric gases into space -- between ~0.1-4% of its atmosphere's total mass every billion years.

As far back as the year 2000, it was predicted that helium would be one of the most readily-detectable gases on giant exoplanets, but until now, searches were unsuccessful.

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Physicists find signs of a time crystal

Yale physicists looked for a signature of a discrete time crystal within a crystal of monoammonium phosphate.

Yale physicists have uncovered hints of a time crystal -- a form of matter that "ticks" when exposed to an electromagnetic pulse -- in the last place they expected: a crystal you might find in a child's toy.

The discovery means there are now new puzzles to solve, in terms of how time crystals form in the first place.

Ordinary crystals such as salt or quartz are examples of three-dimensional, ordered spatial crystals. Their atoms are arranged in a repeating system, something scientists have known for a century.

Time crystals, first identified in 2016, are different. Their atoms spin periodically, first in one direction and then in another, as a pulsating force is used to flip them. That's the "ticking." In addition, the ticking in a time crystal is locked at a particular frequency, even when the pulse flips are imperfect.

Scientists say that understanding time crystals may lead to improvements in atomic clocks, gyroscopes, and magnetometers, as well as aid in building potential quantum technologies. The U.S. Department of Defense recently announced a program to fund more research into time crystal systems.

Yale's new findings are described in a pair of studies, one in Physical Review Letters and the other in Physical Review B. The studies represent the second known experiment observing a telltale signature for a discrete time crystal (DTC) in a solid. Previous experiments led to a flurry of media attention in the past year.

"We decided to try searching for the DTC signature ourselves," said Yale physics professor Sean Barrett, principal investigator for the two new studies. "My student Jared Rovny had grown monoammonium phosphate (MAP) crystals for a completely different experiment, so we happened to have one in our lab."

MAP crystals are considered so easy to grow that they are sometimes included in crystal growing kits aimed at youngsters. It would be unusual to find a time crystal signature inside a MAP crystal, Barrett explained, because time crystals were thought to form in crystals with more internal "disorder."

The researchers used nuclear magnetic resonance (NMR) to look for a DTC signature -- and quickly found it. "Our crystal measurements looked quite striking right off the bat," Barrett said. "Our work suggests that the signature of a DTC could be found, in principle, by looking in a children's crystal growing kit."

Another unexpected thing happened, as well. "We realized that just finding the DTC signature didn't necessarily prove that the system had a quantum memory of how it came to be," said Yale graduate student Robert Blum, a co-author on the studies. "This spurred us to try a time crystal 'echo,' which revealed the hidden coherence, or quantum order, within the system," added Rovny, also a Yale graduate student and lead author of the studies.

Barrett noted that his team's results, combined with previous experiments, "present a puzzle" for theorists trying to understand how time crystals form.

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Butchered Rhino Suggests Humans Lived in the Philippines 709,000 Years Ago

Homo erectus

Since the discovery in 2007 of Callao Man — represented by a Homo sapiens foot bone excavated at Callao Cave — humans were thought to have first lived in the Philippines about 67,000 years ago.

Now that number needs to be multiplied nearly 11 times, as an international team of researchers has just discovered strong evidence that early humans were in the Philippines by at least 709,000 years ago. The evidence, reported in the journal Nature, consists of 57 stone tools and an almost complete disarticulated skeleton of a butchered rhinoceros.

"There are obviously two questions to answer at present," lead author Thomas Ingicco of the National Museum of Natural History in Paris told Seeker. "One is who made the stone tools and butchered the rhino."

"The other question is the origin of the dispersion," he added, referring to how the toolmakers and rhino wound up in a bucolic part of the Philippines.

The new findings, as well as prior research, provide clues.

First, there is the location of the artifacts and animal bones, which also include the remains of brown deer, monitor lizards, freshwater turtles, and stegodons — members of an extinct genus similar to elephants and mammoths. All were found at a site called Kalinga in the Cagayan Valley of northern Luzon Island, Philippines.

"By 700,000 years ago, Homo erectus seems to have been present everywhere in Asia," Ingicco said. "We have fossils from China and Java in Indonesia, and some are much older than the Kalinga site as we have evidence as early as 1.8 million years ago in those places."

The Kalinga toolmakers therefore could have been Homo erectus individuals. They might have traveled to the Philippines along one of four possible gateways, according to Ingicco and his team. The first, a northern route, is from China via Taiwan. The second, a southern approach, is from Sulawesi via the Sangihe Islands. The third, a southwestern route, is from Borneo via the Sulu Archipelago, and the fourth, a northwestern approach, is from Borneo via Palawan Island.

The trip perhaps was not intentional.

"Colonization of the islands could have been possible thanks to natural rafts, such as floating mangroves that typhoons occasionally break off the coast," Ingicco said. "These floating islands would have come with animals and possibly hominins (early humans) on them. Such natural rafts are quite well documented for historical periods and it is therefore a likely way of colonizing Luzon Island during the mid-Pleistocene by hominins."

He added, however, that "floating islands cannot be recovered by archaeological means nor can some kind of watercraft for such an old archaeological site."

The latter is important, because the scientists cannot rule out that the Kalinga toolmakers constructed their own boat, raft, or other means of water transportation. The distance then was too far for human swimming, so the scientists can at least negate that idea.

"If these hominins were capable of constructing some sort of watercraft, then it would indeed be an extraordinary discovery," Ingicco said.

Professor Chris Stringer of the Natural History Museum holds his hand over a Homo floresiensis skull (L) that was found at a cave site called Liang Bua that belonged to an individual who, while fully adult, was barley a meter tall and had a skull the size of a grapefruit.

The researchers also cannot rule out that the Kalinga toolmakers were Homo floresiensis, aka the Hobbit Humans, so named because of their diminutive size and the popularity of "The Lord of the Rings" film series that was in theaters during the time of the hominins' discovery. The island of Flores, where Homo floresiensis remains were found, is just south of the Philippines.

Conversely, the Kalinga toolmakers could have eventually made their way down to Flores, and Homo floresiensis evolved from them. They could have been small even before they took such a hypothetical journey.

Ingicco explained, "Luzon Island might have been the place for similar endemic evolution of hominins into dwarfism, just like what happened on Flores."

Caley Orr of the University of Colorado, Denver has studied Homo floresiensis and other early humans. Orr told Seeker that it has been previously theorized "that a population of Homo erectus was stranded on the island of Flores and became 'dwarfed' over time, which sometimes happens to larger animals that adapt to small island environments."

Orr added, "Homo floresiensis probably went extinct by at least 13,000 years ago." That is relatively recent, in terms of overall human history.

Ignicco and his colleagues say it is also possible that an entirely different and as-of-yet unknown hominin made the Kalinga tools and was the first to settle the Philippines. The tools unfortunately do not shed light on this matter.

Made from pebbles, the tools were simple in construction but knapped — that is, shaped by striking, which in this case occurred on anvils.

"Anvil technology is actually found in different places around the world, and it seems to always be used whenever the pebbles are too hard to be knapped in these other places," Ignicco said. "In France, for example, anvils were used to produce tools from quartzite by 1.1 million years ago."

One excavated pebble at Kalinga was five times larger than the rest. The researchers do not think that it arrived at the site by natural transport, such as flowing in from a river, so they suspect that it was intentionally brought to the area by the early humans, who perhaps used it as an anvil or in their butchering of the rhino.

The rhino — the now-extinct Rhinoceros philippinensis — appears to have been savored. Cut marks reveal that its consumers likely stripped off the meat and smashed its bones to gain access to the animal's marrow. Remarkably, 75 percent of the rhino's remains were found during the excavation.

Prehistoric human migrants often seemed to adhere to a simple rule: follow the meat — or fish. Evidence is mounting that early humans tracked animal migrations on land, leading them into new territories. During settlement of the Americas, for example, the kelp highway hypothesis holds that some of the first Americans colonized the New World by following coastlines and seafood-rich kelp forests from north to south.

Read more at Seeker

Ample warning of supervolcano eruptions likely, experts say

Erupting volcano

Concern over the potential imminent eruptions of Earth's supervolcanoes, like Taupo in New Zealand or Yellowstone in the United States, may be quelled by the results of a new study suggesting that geological signs pointing to a catastrophic eruption would be clear far in advance.

To help forecast supervolcano eruptions, the study led by the University of Illinois has quantified the often-overlooked effects of tectonic stress on the rocks that house these sleeping giants, and suggests that people need not be quick to panic -- at least not yet.

In the study, researchers set out to investigate regional-scale tectonic stress and unexpectedly found that their models could help forecast supervolcano eruption timing and inform experts on what to expect, geologically, well before an eruption.

"Traditionally, it is thought that eruptions occur when the pressure caused by hot magma overtakes the strength of a volcano's roof rock," said geology professor Patricia Gregg. "But supervolcanoes tend to occur in areas of significant tectonic stress, where plates are moving toward, past or away from each other. That plate motion will affect model calculations."

Gregg, graduate student Haley Cabaniss and Pomona College geology professor Eric Grosfils published their findings in the journal Geophysical Research Letters.

The team created a model based on the Taupo Volcanic Zone in northern New Zealand. They chose this system because of its relatively uncomplicated extensional tectonic setting -- the type of area often associated with supervolcanoes. However, their models found that any tectonic stress would have a profound effect on the stability of supervolcanoes.

"It does not matter if it is extensional, compressional or shear stress," Cabaniss said. "Any tectonic stress will help destabilize rock and trigger eruptions, just on slightly different timescales. The remarkable thing we found is that the timing seems to depend not only on tectonic stress, but also on whether magma is being actively supplied to the volcano."

Using their model, the team looked at scenarios with different amounts of stress, tectonic plate movement and magma supply. They found that in any given tectonic setting, the magma reservoirs inside of supervolcanoes appear to remain stable for hundreds to thousands of years while new magma is being actively suppled to the system.

"We were initially surprised by this very short timeframe of hundreds to thousands of years," Gregg said. "But it is important to realize that supervolcanes can lay dormant for a very long time, sometimes a million years or more. In other words, they may remain stable, doing almost nothing for 999,000 years, then start a period of rejuvenation leading to a large-scale eruption."

Of course, panic sets in whenever Yellowstone or Taupo experience any change in seismic or geyser activity, but this research suggests that the precursors to catastrophic eruption will be far greater and long-lasting than anything yet documented, the researchers said.

"When new magma starts to rejuvenate a supervolcano system, we can expect to see massive uplift, faulting and earthquake activity," Gregg said. "Far greater than the meter-scale events we have seen in recent time. We are talking on the range of tens to hundreds of meters of uplift. Even then, our models predict that the system would inflate for hundreds to thousands of years before we witness catastrophic eruption."

Read more at Science Daily

Reef fish inherit tolerance to warming oceans

The study species, spiny chromis (Acanthochromis polyacanthus) on the Great Barrier Reef.

In a rapidly changing climate, the decline of animal populations is a very real concern. Today, an international team of researchers report new evidence of reef fish adjusting to global warming conditions at the genetic level.

For the first time, researchers from the ARC Centre of Excellence for Coral Reef Studies (Coral CoE) and the King Abdullah University of Science & Technology (KAUST), have found that reef fish can inherit from their parents the genetic tools to adjust to ocean warming.

"When parents are exposed to an increase in water temperature, we found that their offspring improved their performance in these otherwise stressful conditions by selectively modifying their epigenome," said senior author Prof Philip Munday of Coral CoE at James Cook University.

Epigenetic change refers to chemical modifications in the DNA that signals genes to be switched on or off. A range of factors, including disease, famine, or in the case of this research, heat stress, can stimulate these subtle changes.

In this study, when both parent and offspring experienced the same elevated water temperatures, responsive changes in their epigenome, via selective DNA methylation, were observed that enhanced the next generation's ability to cope with the new, warmer temperatures.

"We reared spiny chromis damselfish, a common Indo-Pacific reef fish, for two generations under three different water temperatures, up to 3 degrees Celsius warmer than current-day ocean temperatures," explained co-author Prof Timothy Ravasi of KAUST.

"The next generation appeared to be advantaged by parental exposure to elevated temperatures. The offspring's altered gene expression, also referred to as 'acclimation,' allowed them to maximise oxygen consumption and energy use."

"Acclimation may buffer populations against the impacts of rapid environmental change and provide time for genetic adaptation to catch up over the longer term," said Prof Munday.

Read more at Science Daily

Old data, new tricks: Fresh results from NASA's Galileo spacecraft 20 years on

In this illustration, the moon Ganymede orbits the giant planet Jupiter. Ganymede is depicted with auroras, which were observed by NASA's Hubble Space Telescope.

Far across the solar system, from where Earth appears merely as a pale blue dot, NASA's Galileo spacecraft spent eight years orbiting Jupiter. During that time, the hardy spacecraft -- slightly larger than a full-grown giraffe -- sent back spates of discoveries on the gas giant's moons, including the observation of a magnetic environment around Ganymede that was distinct from Jupiter's own magnetic field. The mission ended in 2003, but newly resurrected data from Galileo's first flyby of Ganymede is yielding new insights about the moon's environment -- which is unlike any other in the solar system.

"We are now coming back over 20 years later to take a new look at some of the data that was never published and finish the story," said Glyn Collinson, lead author of a recent paper about Ganymede's magnetosphere at NASA's Goddard Space Flight Center in Greenbelt, Maryland. "We found there's a whole piece no one knew about."

The new results showed a stormy scene: particles blasted off the moon's icy surface as a result of incoming plasma rain, and strong flows of plasma pushed between Jupiter and Ganymede due to an explosive magnetic event occurring between the two bodies' magnetic environments. Scientists think these observations could be key to unlocking the secrets of the moon, such as why Ganymede's auroras are so bright.

In 1996, shortly after arriving at Jupiter, Galileo made a surprising discovery: Ganymede had its own magnetic field. While most planets in our solar system, including Earth, have magnetic environments -- known as magnetospheres -- no one expected a moon to have one.

Between 1996 and 2000, Galileo made six targeted flybys of Ganymede, with multiple instruments collecting data on the moon's magnetosphere. These included the spacecraft's Plasma Subsystem, or PLS, which measured the density, temperature and direction of the plasma -- excited, electrically charged gas -- flowing through the environment around Galileo. New results, recently published in the journal Geophysical Research Letters, reveal interesting details about the magnetosphere's unique structure.

We know that Earth's magnetosphere -- in addition to helping make compasses work and causing auroras -- is key to in sustaining life on our planet, because it helps protect our planet from radiation coming from space. Some scientists think Earth's magnetosphere was also essential for the initial development of life, as this harmful radiation can erode our atmosphere. Studying magnetospheres throughout the solar system not only helps scientists learn about the physical processes affecting this magnetic environment around Earth, it helps us understand the atmospheres around other potentially habitable worlds, both in our own solar system and beyond.

Ganymede's magnetosphere offers the chance to explore a unique magnetic environment located within the much larger magnetosphere of Jupiter. Nestled there, it's protected from the solar wind, making its shape different from other magnetospheres in the solar system. Typically, magnetospheres are shaped by the pressure of supersonic solar wind particles flowing past them. But at Ganymede, the relatively slower-moving plasma around Jupiter sculpts the moon's magnetosphere into a long horn-like shape that stretches ahead of the moon in the direction of its orbit.

Flying past Ganymede, Galileo was continually pummeled by high-energy particles -- a battering the moon is also familiar with. Plasma particles accelerated by the Jovian magnetosphere, continually rain down on Ganymede's poles, where the magnetic field channels them toward the surface. The new analysis of Galileo PLS data showed plasma being blasted off the moon's icy surface due to the incoming plasma rain.

"There are these particles flying out from the polar regions, and they can tell us something about Ganymede's atmosphere, which is very thin," said Bill Paterson, a co-author of the study at NASA Goddard, who served on the Galileo PLS team during the mission. "It can also tell us about how Ganymede's auroras form."

Ganymede has auroras, or northern and southern lights, just like Earth does. However, unlike our planet, the particles causing Ganymede's auroras come from the plasma surrounding Jupiter, not the solar wind. When analyzing the data, the scientists noticed that during its first Ganymede flyby, Galileo fortuitously crossed right over Ganymede's auroral regions, as evidenced by the ions it observed raining down onto the surface of the moon's polar cap. By comparing the location where the falling ions were observed with data from Hubble, the scientists were able to pin down the precise location of the auroral zone, which will help them solve mysteries, such as what causes the auroras.

As it cruised around Jupiter, Galileo also happened to fly right through an explosive event caused by the tangling and snapping of magnetic field lines. This event, called magnetic reconnection, occurs in magnetospheres across our solar system. For the first time, Galileo observed strong flows of plasma pushed between Jupiter and Ganymede due to a magnetic reconnection event occurring between the two magnetospheres. It's thought that this plasma pump is responsible for making Ganymede's auroras unusually bright.

Read more at Science Daily

Physics of a glacial 'slushy' reveal granular forces on a massive scale

The ice ridge in the photo shows the terminus of Jakobshavn Glacer at the ice-ocean border, and the broken clog of icebergs in front of it, known as an ice mélange.

The laws for how granular materials flow apply even at the giant, geophysical scale of icebergs piling up in the ocean at the outlet of a glacier, scientists have shown.

The Proceedings of the National Academy of Sciences (PNAS) published the findings, describing the dynamics of the clog of icebergs -- known as an ice mélange -- in front of Greenland's Jakobshavn Glacier. The fast-moving glacier is considered a bellwether for the effects of climate change.

"We've connected microscopic theories for the mechanics of granular flowing with the world's largest granular material -- a glacial ice mélange," says Justin Burton, an assistant professor of physics at Emory University and lead author of the paper. "Our results could help researchers who are trying to understand the future evolution of the Greenland and Antarctica ice sheets. We've showed that an ice mélange could potentially have a large and measurable effect on the production of large icebergs by a glacier."

The National Science Foundation funded the research, which brought together physicists who study the fundamental mechanics of granular materials in laboratories and glaciologists who spend their summers exploring polar ice sheets.

"Glaciologists generally deal with slow, steady deformation of glacial ice, which behaves like thick molasses -- a viscous material creeping towards the sea," says co-author Jason Amundson, a glaciologist at the University of Alaska Southeast, Juneau. "Ice mélange, on the other hand, is fundamentally a granular material -- essentially a giant slushy -- that is governed by different physics. We wanted to understand the behavior of ice mélange and its effects on glaciers."

For thousands of years, the massive glaciers of Earth's polar regions have remained relatively stable, the ice locked into mountainous shapes that ebbed in warmer months but gained back their bulk in winter. In recent decades, however, warmer temperatures have started rapidly thawing these frozen giants. It's becoming more common for sheets of ice -- some one kilometer tall -- to shift, crack and tumble into the sea, splitting from their mother glaciers in an explosive process known as calving.

Jakobshavn Glacier is advancing as fast as 50 meters per day until it reaches the ocean edge, a point known as the glacier terminus. About 35 billion tons of icebergs calve off of Jakobshavn Glacier each year, spilling out into Greenland's Ilulissat fjord, a rocky channel that is about five kilometers wide. The calving process creates a tumbling mix of icebergs which are slowly pushed through the fjord by the motion of the glacier. The ice mélange can extend hundreds of meters deep into the water but on the surface it resembles a lumpy field of snow which inhibits, but cannot stop, the motion of the glacier.

"An ice mélange is kind of like purgatory for icebergs, because they've broken off into the water but they haven't yet made it out to open ocean," Burton says.

While scientists have long studied how ice forms, breaks and flows within a glacier, no one had quantified the granular flow of an ice mélange. It was an irresistible challenge to Burton. His lab creates experimental models of glacial processes to try to quantify their physical forces. It also uses microscopic particles as a model to understand the fundamental mechanics of granular, amorphous materials, and the boundary between a free-flowing state and a rigid, jammed-up one.

"Granular material is everywhere, from the powders that make up pharmaceuticals to the sand, dirt and rocks that shape our Earth," Burton says. And yet, he adds, the properties of these amorphous materials are not as well understood as those of liquids or crystals.

In addition to Amundson, Burton's co-authors on the PNAS paper include glaciologist Ryan Cassotto -- formerly with the University of New Hampshire and now with the University of Colorado Boulder -- and physicists Chin-Chang Kuo and Michael Dennin, from the University of California, Irvine.

The researchers characterized both the flow and mechanical stress of the Jacobshavn ice mélange using field measurements, satellite data, lab experiments and numerical modeling. The results quantitatively describe the flow of the ice mélange as it jams and unjams during its journey through the fjord. The paper also showed how the ice mélange can act as a "granular ice shelf" in its jammed state, buttressing even the largest icebergs calved into the ocean.

Read more at Science Daily

Study explores link between curiosity and school achievement

Researchers know that certain factors give children a leg up when it comes to school performance. Family income, access to early childhood programs and home environment rank high on the list.

Now, researchers are looking at another potentially advantageous element: curiosity.

The more curious the child, the more likely he or she may be to perform better in school -- regardless of economic background -- suggests a new study published in Pediatric Research.

Researchers at University of Michigan C.S. Mott Children's Hospital and the Center for Human Growth and Development analyzed data from 6,200 kindergartners from the Early Childhood Longitudinal Study, Birth Cohort. The cohort is a nationally representative, population-based study sponsored by the U.S. Department of Education that has followed thousands of children since birth in 2001.

The U-M team measured curiosity based on a behavioral questionnaire from parents and assessed reading and math achievement among kindergartners.

The most surprising association offered new insight: Children with lower socioeconomic status generally have lower achievement than peers, but those who were characterized as curious performed similarly on math and reading assessments as children from higher income families.

"Our results suggest that while higher curiosity is associated with higher academic achievement in all children, the association of curiosity with academic achievement is greater in children with low socioeconomic status," says lead researcher Prachi Shah, M.D., a developmental and behavioral pediatrician at Mott and an assistant research scientist at U-M's Center for Human Growth and Development.

The findings present an opportunity for families, educators and policymakers.

"Curiosity is characterized by the joy of discovery and the desire for exploration and is characterized by the motivation to seek answers to the unknown," Shah says. "Promoting curiosity in children, especially those from environments of economic disadvantage may be an important, underrecognized way to address the achievement gap."

Cultivating curious kids

When it comes to nurturing curiosity, the quality of the early environment matters.

Children who grow up in financially secure conditions tend to have greater access to resources to encourage reading and math academic achievement, whereas those from poorer communities are more likely to be raised in less stimulating environments, Shah notes. In less-stimulating situations, the drive for academic achievement is related to a child's motivation to learn, or curiosity, she explains.

Parents of children enrolled in the longitudinal study were interviewed during home visits; the children were assessed when they were nine months and two years old, and again when they entered preschool and kindergarten. Reading levels, math skills and behavior were measured in these children when they reached kindergarten in 2006 and 2007.

U-M researchers factored in another important known contributor to academic achievement known as "effortful control," or the ability to stay focused in class. They found that even independent of those skills, children who were identified as curious fared well in math and reading.

"These findings suggest that even if a child manifests low effortful control, they can still have more optimal academic achievement, if they have high curiosity" Shah says. "Currently, most classroom interventions have focused on the cultivation of early effortful control and a child's self-regulatory capacities, but our results suggest that an alternate message, focused on the importance of curiosity, should also be considered."

Shah notes that fostering early academic achievement in young children has been a longstanding goal for pediatricians and policymakers, with a growing awareness of the role social-emotional skills in school readiness.

And while more study is needed, similar efforts to boost curiosity could one day follow.

"While our results suggest that the promotion of curiosity may be a valuable intervention target to foster early academic achievement, with particular advantage for children in poverty, further research is needed to help us better understand how to develop interventions to cultivate curiosity in young children.

Read more at Science Daily

We still don't know how strange celibate animals evolve

This is one of the species in the study: Rotaria macrura.

A new study has cast doubt on leading theory for how tiny creatures have evolved for tens of millions of years -- without ever having sex.

Most animals reproduce sexually, a process which shuffles genes from parent to offspring. This makes natural selection more efficient and allows animals to evolve defences against changing environmental conditions more rapidly, especially new diseases.

Bdelloid rotifers however appear to be an exception to this rule: they are all female, and their offspring are clones of their mothers. Bdelloids are microscopic animals that live in freshwater and damp habitats across the world. Despite their apparent lack of sex, we know they have evolved for tens of millions of years into more than 500 species.

By studying their genomes -- the set of all the genes that define an animal's characteristics -- researchers thought they had identified an explanation for how bdelloids had 'gotten away' with no sex for millions of years.

However, a new study, published today in PLOS Biology and led by Imperial College London researchers, reveals this mechanism may not be the main explanation for the bdelloids' success.

Many species of bdelloid endure periods of drying out, called desiccation. Although they survive desiccation, the process damages their DNA, which they need to repair when rehydrated.

Based on a previous study of the genome of a species that survives desiccation, researchers had proposed that the repair of DNA might remove some of the problems of being asexual, for example by removing harmful mutations and possibly allowing occasional recombination of genes to occur.

This theory made key predictions about what the genomes of the small number of bdelloid species that cannot survive desiccation should look like. The new study looked at the genomes of three further species, including some that do not undergo desiccation.

The researchers found that the predicted differences between species that can and cannot survive desiccation were not observed. This suggests that DNA repair following desiccation may not be as important as previously thought, and that other factors may need to be considered to explain bdelloid evolution.

Senior researcher Professor Tim Barraclough, from the Department of Life Science at Imperial, said: "We have been building up this story of how these creatures manage to change based on their remarkable ability to survive desiccation.

"However, when we open up the investigation to other sexless species of bdelloid that do not dry out, we find that the story does not play out. We thought we were understanding more about these creatures, but this is a spanner in the works."

Although the latest study shows that desiccation is not key to genome changes, the team did confirm that all the species investigated so far show unusual levels of 'horizontal gene transfer' -- which means they incorporate and use foreign DNA from distantly related organisms in their genomes.

Bdelloid species are known to have taken up thousands of genes from plants, bacteria, fungi, and single-celled organisms. Different species appear to have adapted to their unique environments by taking up DNA that benefits their survival, providing another route to evolution.

It is not known exactly how bdelloids incorporate foreign DNA, but DNA repair following desiccation has been proposed as one route for those species that undergo drying out. Next, the team want to look more closely at these foreign genes for clues as to how they were acquired.

They also want to study the genomes of individuals within the same population over time to see how their genomes change.

Finally, although no males have ever been found, this new study of rotifers' genomes suggests scientists can't rule out sex as firmly as previously thought. Previous evidence had suggested that the structure of the bdelloid genome made conventional sex impossible.

Sexual animals have two copies of each gene arranged along matching chromosomes, one from the father and one from the mother. The first bdelloid genome sequenced revealed that the two copies of genes were often on the same chromosome, which is incompatible with their inheritance on chromosomes from a father and a mother. The new study, however, did not find these same patterns in the three new genomes.

Read more at Science Daily

Vultures reveal critical Old World flyways

These are movements of tracked Egyptian vultures over the course of a year.

It's not easy to catch an Egyptian vulture. Evan Buechley knows. He's hunkered down near garbage dumps from Ethiopia to Armenia, waiting for the highly intelligent birds to trigger a harmless trap. But no matter how well he and other researchers hid the traps, he says, "somehow the birds could always sense that something was up."

Eventually Buechley, a postdoctoral scholar at the University of Utah and HawkWatch International, and his colleagues caught and tagged a total of 45 vultures from 2012-2016. The Egyptian Vulture is an endangered species, and by tracking them Buechley and colleagues were able to learn more about where they eat, breed and migrate.

These vultures migrated along the Red Sea Flyway -- a large area connecting the summer and winter ranges of birds in Eastern Europe, Central Asia, the Middle East and Africa -- and their travel routes revealed migratory bird corridors and bottlenecks. Identifying bottlenecks -- i.e. places where birds concentrate on migration -- helps bird conservationists know what areas to focus on and get the most bang for their buck, since a large percentage of a species' population can pass through these small areas.

"The Red Sea Flyway connects birds from Eastern Europe, Central Asia, the Middle East -- all those birds that migrate into Africa," Buechley says. "But because of political instability in some countries and harsh desert environs throughout, it's minimally studied. There's not a lot of conservation happening. It's a big research gap."

Buechley and his international colleagues (see full list at bottom) published their results in two papers, one appearing in Biodiversity and Conservation on March 19, 2018, and another appearing in the Journal of Avian Biology today.

Migration routes

The data shows that the vultures traveled as far as 7,500 miles (12,000 kilometers) in a single migration, at up to around 223 miles (360 km) per day. "They're traveling far and traveling fast," Buechley says.

The vultures are just one species out of around 35 large soaring bird species that migrate along the Red Sea Flyway. There are dozens more small birds that migrate here, as well. It's the second-largest migratory flyway in the world, behind only the Americas Flyway, which connects North and South America.

On some flyways, migratory birds are funneled into narrow passageways over land due to geographic features, Buechley says. Large birds like Egyptian vultures need to glide to conserve energy. They use rising columns of thermal air to keep soaring without needing to constantly flap their 5.6 foot-wingspan (1.7 m) -- a kind of avian cruise control. These thermals rarely exist over the ocean, so birds tend to hug coasts and mountain ridges.

That's borne out in the flight paths Buechley and his colleagues reported. The main bottlenecks are the Bab-el-Mandeb Strait for southern-bound birds and the Suez Canal zone for northern-bound birds. The former is where the birds enter Africa from the Arabian Peninsula, by hopping over the narrow strait at the southern end of the Red Sea.

With the key bottlenecks identified, the researchers then looked at how well protected these areas were. Unfortunately, none of the areas within the most important bird bottlenecks receive any federal protection from the nations in which they sit, the analyses show. However, Important Bird and Biodiversity Areas (IBAs) -- places recognized for their international importance for conservation -- do overlap some of these areas and future work could focus at these sites. Steffen Oppel, a scientist who works in the global network of BirdLife International which is responsible for designating IBAs, says that recognizing the importance of such bottlenecks is vital to influence developments that may harm birds on migration. The Migratory Soaring Bird Sensitivity Tool allows developers of wind farms, for example, to assess how likely it is that their turbines may affect migrating birds.

Wind turbines are just one of the major hazards that vultures face along their journeys. Illegal shooting and poisoning is a concern throughout their ranges, Buechley says. Also, the birds rest on power distribution structures, which present the risk of collision and electrocution.

How we can help

Although the report seems dire, Buechley says there's hope. The Africa side of the Bab-el-Mandeb Strait sits in the nation of Djibouti. "It's bordered by Yemen and Somalia, but Djibouti is a safe and stable country," he says. "And that's where the bottleneck is. The most important place for the birds is actually a place where researchers and conservationists can work."

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If pigs could fly: How can forests regenerate without birds?

The trunk of a native cycad, Cycas micronesica, arches gracefully over the karst floor of a limestone forest on Guam.

Human activity continues to shape environmental systems around the world creating novel ecosystems that are increasingly prevalent in what some scientists call the Anthropocene (the age of humans). The island of Guam is well known as a textbook case for the devastating effects of invasive species on island ecosystems with the extirpation of most of the forest dwelling birds due to brown tree snake predation. The loss of native birds has resulted in a loss of forest seed dispersers. Recent research conducted by lead author Ann Marie Gawel, based on her University of Guam master's thesis, has found an unlikely forest ally, feral pigs.

With the loss of birds in the limestone forests on Guam, seed dispersal for native plants has become problematic. The damage caused by ungulates, introduced deer and pigs, has been documented in tropical forests worldwide. Less documented is the effect of these animals on seed dispersal of native and nonnative forest plant species.

Gawel's study examined scat from deer and pigs foraging in the limestone karst forests of northern Guam. Her findings indicate that pigs, featherless and flightless, might be one of the last seed dispersers left on the island to assist in forest regeneration. Particular to limestone forests, where pigs would be hard pressed to find places to wallow and root, this study found negative impacts from the presence of deer but did not detect negative impacts from pigs.

This finding is important for informing conservation and forest restoration practices. Although the removal of ungulates has proven beneficial in managing forest systems; for Guam, removing pigs from limestone forests may have a detrimental effect on the regeneration of the plant communities of those forests. "The browsing preferences of ungulates on the island of Guam have directly impacted the diversity and make up of forest species for many years. Our research indicates the need for ungulate control that addresses the ecological role that pigs have been providing to limestone forests since the loss of native seed dispersers," noted Gawel.

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Stellar thief is the surviving companion to a supernova

Seventeen years ago, astronomers witnessed supernova 2001ig go off 40 million light-years away in the galaxy NGC 7424, in the southern constellation Grus, the Crane. Shortly after, scientists photographed the supernova with the European Southern Observatory's Very Large Telescope (VLT) in 2002. Two years later, they followed up with the Gemini South Observatory, which hinted at the presence of a surviving binary companion. As the supernova's glow faded, scientists focused Hubble on that location in 2016. They pinpointed and photographed the surviving companion, which was possible only due to Hubble's exquisite resolution and ultraviolet sensitivity. Hubble observations of SN 2001ig provide the best evidence yet that some supernovas originate in double-star systems.

Seventeen years ago, astronomers witnessed a supernova go off 40 million light-years away in the galaxy called NGC 7424, located in the southern constellation Grus, the Crane. Now, in the fading afterglow of that explosion, NASA's Hubble has captured the first image of a surviving companion to a supernova. This picture is the most compelling evidence that some supernovas originate in double-star systems.

"We know that the majority of massive stars are in binary pairs," said Stuart Ryder from the Australian Astronomical Observatory (AAO) in Sydney, Australia and lead author of the study. "Many of these binary pairs will interact and transfer gas from one star to the other when their orbits bring them close together."

The companion to the supernova's progenitor star was no innocent bystander to the explosion. It siphoned off almost all of the hydrogen from the doomed star's stellar envelope, the region that transports energy from the star's core to its atmosphere. Millions of years before the primary star went supernova, the companion's thievery created an instability in the primary star, causing it to episodically blow off a cocoon and shells of hydrogen gas before the catastrophe.

The supernova, called SN 2001ig, is categorized as a Type IIb stripped-envelope supernova. This type of supernova is unusual because most, but not all, of the hydrogen is gone prior to the explosion. This type of exploding star was first identified in 1987 by team member Alex Filippenko of the University of California, Berkeley.

How stripped-envelope supernovas lose that outer envelope is not entirely clear. They were originally thought to come from single stars with very fast winds that pushed off the outer envelopes. The problem was that when astronomers started looking for the primary stars from which supernovas were spawned, they couldn't find them for many stripped-envelope supernovas.

"That was especially bizarre, because astronomers expected that they would be the most massive and the brightest progenitor stars," explained team member Ori Fox of the Space Telescope Science Institute in Baltimore. "Also, the sheer number of stripped-envelope supernovas is greater than predicted." That fact led scientists to theorize that many of the primary stars were in lower-mass binary systems, and they set out to prove it.

Looking for a binary companion after a supernova explosion is no easy task. First, it has to be at a relatively close distance to Earth for Hubble to see such a faint star. SN 2001ig and its companion are about at that limit. Within that distance range, not many supernovas go off. Even more importantly, astronomers have to know the exact position through very precise measurements.

In 2002, shortly after SN 2001ig exploded, scientists pinpointed the precise location of the supernova with the European Southern Observatory's Very Large Telescope (VLT) in Cerro Paranal, Chile. In 2004, they then followed up with the Gemini South Observatory in Cerro Pachón, Chile. This observation first hinted at the presence of a surviving binary companion.

Knowing the exact coordinates, Ryder and his team were able to focus Hubble on that location 12 years later, as the supernova's glow faded. With Hubble's exquisite resolution and ultraviolet capability, they were able to find and photograph the surviving companion -- something only Hubble could do.

Prior to the supernova explosion, the orbit of the two stars around each other took about a year.

When the primary star exploded, it had far less impact on the surviving companion than might be thought. Imagine an avocado pit -- representing the dense core of the companion star -- embedded in a gelatin dessert -- representing the star's gaseous envelope. As a shock wave passes through, the gelatin might temporarily stretch and wobble, but the avocado pit would remain intact.

In 2014, Fox and his team used Hubble to detect the companion of another Type IIb supernova, SN 1993J. However, they captured a spectrum, not an image. The case of SN 2001ig is the first time a surviving companion has been photographed. "We were finally able to catch the stellar thief, confirming our suspicions that one had to be there," said Filippenko.

Perhaps as many as half of all stripped-envelope supernovas have companions -- the other half lose their outer envelopes via stellar winds. Ryder and his team have the ultimate goal of precisely determining how many supernovas with stripped envelopes have companions.

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