Earth

Life cycles for birds, insects and trees are shifting in this current era of a rapidly changing climate. How migration patterns, in particular, are changing and whether birds can track climate change is an open question.

Kyle Horton, assistant professor at Colorado State University, led a new study analyzing nocturnal bird migration that he hopes will lead to more answers about shifting migration patterns. He and the research team used 24 years of radar data from NOAA, the National Oceanic and Atmospheric Administration, for the study.

The research team - including scientists from the Cornell Lab of Ornithology and the University of Massachusetts - found that spring migrants were likely to pass certain stops earlier now than they would have 20 years ago. Temperature and migration timing were closely aligned, with the greatest changes in migration timing occurring in regions warming most rapidly. During fall, shifts in migration timing were less apparent.

The study, one of the first to examine the impacts of climate change on migration timing at a continental scale, is published December 16 in Nature Climate Change.

Analysis using cloud computing revealed patterns of millions of birds

Horton described the breadth of the research as "critically important," with the team observing the nocturnal migratory behaviors of hundreds of species representing billions of birds.

"To see changes in timing at continental scales is truly impressive, especially considering the diversity of behaviors and strategies used by the many species the radars capture," he said. Yet while the team saw these shifts, Horton noted that this doesn't necessarily mean that migrants are keeping pace with climate change.

Migratory birds serve an important role in ecosystems. They eat and take insects off the land, disperse seeds and serve other significant functions, including measuring health in these ecosystems.

Andrew Farnsworth, the study's senior author and a research associate at Cornell Lab of Ornithology, said the team's research answered, for the first time, key questions on birds and climate change.

"Bird migration evolved largely as a response to changing climate," he said. "It's a global phenomenon involving billions of birds annually. And it's not a surprise that birds' movements track changing climates. But how assemblages of bird populations respond in an era of such rapid and extreme changes in climate has been a black box. Capturing scales and magnitudes of migration in space and time has been impossible until recently."

Researchers accessed NOAA datasets through Amazon Web Services as part of the agency's Big Data Project, designed to provide access to data in a more efficient way.

Horton said that this access to the data and cloud computing greatly enhanced the team's ability to synthesize the findings.

"To process all of these data, without cloud computing, it would have taken over a year of continuous computing," he said. Instead, the team crunched the numbers in about 48 hours.

While Amazon Web Services provided access to the data, new algorithms designed by scientists at the University of Massachusetts revealed the potential of these radar data for biologists. Specifically, the scientists designed new computer vision techniques to remove weather data, a problem that had challenged biologists from decades.

"Historically, a person had to look at each radar image to determine whether it contained rain or birds," said Dan Sheldon, associate professor of computer science at the University of Massachusetts Amherst. "We developed 'MistNet,' an artificial intelligence system to detect patterns in radar images and remove rain automatically."

Fall migration tends to be 'messier'

Horton, who works in the Department of Fish, Wildlife and Conservation Biology at CSU, said that the lack of change in fall migration patterns was a little surprising, though migration also tends to be a "little bit messier" during those months.

"In the spring, we see bursts of migrants, moving at a fairly rapid pace, ultimately to reach the breeding grounds," he explained. "However, during the fall, there's not as much pressure to reach the wintering grounds, and migration tends to move at a slower, more punctuated pace."

During the fall, birds are not competing for mates, and the path to reach their destination is more relaxed. There's also a wider age range of birds migrating, as the young eventually realize they need to migrate, too. The combination of these factors makes fall migration more challenging to study.

Horton said the findings have implications for understanding future patterns of bird migration, since the birds rely on food and other resources as they travel. Under climate change, the timing of blooming vegetation or emergence of insects may be out of sync with the passage of migratory birds. This seemingly subtle shift could have negative consequences for the health of migratory birds.

Researchers plan to expand their data analysis to include Alaska, where climate change is having more serious impacts than in the lower 48 states in the U.S.

Research on global biodiversity has long assumed that present-day biodiversity patterns reflect present-day factors, namely contemporary climate and human activities. A new study shows that climate changes and human impacts over the last 100,000 years continue to shape patterns of tropical and subtropical mammal biodiversity today -- a surprising finding.

The new research -- coauthored by Kaye E. Reed and Irene Smail, Arizona State University; Lydia Beaudrot, Rice University; Janet Franklin, University of California Riverside; and John Rowan, Andrew Zamora, and Jason M. Kamilar, University of Massachusetts Amherst -- will be published in the Proceedings of the National Academy of Sciences.

Understanding the factors that structure global biodiversity patterns -- the distribution and diversity of life on Earth -- has been of long-standing scientific interest. To date, much of this research has focused on present-day climate, such as average temperature or rainfall, because climate is well-known to influence species geographic distributions and because human-caused climate change is a major threat. Likewise, other recent human impacts are well-known to influence biodiversity and are well-studied, such as deforestation and urbanization of wild lands that destroy habitats for many species.

What many of these studies overlook, however, is that present-day biodiversity patterns are the outcome of thousands of years of changes in Earth's climate and, more recently, prehistoric human activity. Thus, present-day biodiversity patterns need not be primarily driven by recent climate or human impacts. A small but growing body of studies suggest that legacies of the ancient past continue to structure patterns of life on Earth today. Indeed, though this may be the case, global-scale analyses on this issue remained elusive until now.

To tackle this issue, the researchers analyzed a database of 515 mammal communities across the globe. For each community (i.e., an assemblage of mammal species occupying the same area), they collected data on the species present, their ecological characteristics (body size, diet, etc.) and their evolutionary relationships to one another. They used this information to measure the ecological and evolutionary structure of each community and then asked whether it was best explained by present-day climate (current temperature and rainfall), Quaternary paleoclimate changes (changes in temperature and rainfall from around 22,000 years ago and 6,000 years ago to the present), recent human activity (land-use change since the Industrial Revolution) or prehistoric human activity (human-driven mammal extinctions that happened over the last 100,000 years as humans spread across the globe).

The research findings show, for the first time, that current patterns of mammal diversity across the world's tropical and subtropical regions are structured by both past and present climate and human impacts, but specific effects vary by region.

"We have long been interested in finding overarching explanations for what drives mammal diversity across the globe," said John Rowan. "For our research group, this study made us realize that there probably isn't one -- every region of the world has its own distinct history, and that history matters today."

In the Neotropics (South and Central America), for example, mammal communities are strongly influenced by prehistoric human-driven extinctions over the last 100,000 years. When humans arrived in the Neotropics, they caused massive extinctions of the region's mammals, the effects of which linger today in the surviving communities. Conversely, Africa was lightly impacted by these extinctions, and the region's present-day communities are mainly shaped by current and prehistoric climates. Southeast Asia and Madagascar also have their own suite of past and present climatic and human factors that shape them.

These global differences highlight an important finding of the study -- there is no one-size-fits-all explanation for what structures mammal biodiversity across the world. Each of world's major regions has a unique ecological and evolutionary history, and these histories continue to strongly influence the distribution and diversity of mammalian life on Earth.

"Now that we have a global study of the similarities and differences of the overarching effects on mammal communities," said Kaye Reed, "we will continue to explore each region in depth to examine other factors that affected these communities in the past and what that might mean for the future."

The climatic and human-impact legacies of the ancient past can be, and often are, as or more important than their present-day counterparts. As scientists continue to understand global patterns of biodiversity, the researchers suggest that past climate and human impact factors should be incorporated into future studies. They propose that this will result in a more holistic understanding of what drives biodiversity and how it may respond to ongoing and future human-caused changes in the 21st century.

In an article published in Physical Review Letters, Bristol scientists have answered the fundamental question: "Is it possible to move without exerting force on the environment?", by describing the tractionless self-propulsion of active matter.

Understanding how cells move autonomously is a fundamental question for both biologists and physicists.

Experiments on cell motility are commonly done by looking at the motion of a cell on a glass slide under a microscope.

In those conditions, cells are observed to "crawl" on the surface. Crawling is well-understood: cells attach themselves to the surface and use these anchor points to push themselves forward (like crawling on the ground). However, crawling is very inefficient in vivo, where cells move through complex 3D environments.

Scientists from the School of Mathematics at Bristol have identified a different propulsion mechanism particularly suited for cell motion in tissues - one that doesn't rely on force transmission through anchor points.

They found that self-propulsion without traction (=local force on the surrounding environment) is possible if you are made of "active" matter, as cells are. They describe how a drop of active matter can move itself forward in a narrow channel without exerting any force on the walls around it.

Lead author, Dr Aurore Loisy, said: "Tractionless motion is very counterintuitive. We became really excited when we realised that not only it is possible, but also that it provides a plausible explanation to a problem as important as cell motility in tissues.

"Besides, part of the beauty of this tractionless self-propulsion lies in the fact that it is described by an analytical solution of remarkable and unusual simplicity. Due to the complexity (nonlinearity) of the equations that describe active matter, we did not expect to end up with something so simple!"

Active matter is a special kind of matter, ubiquitous in biology, in which metabolic energy is constantly converted into mechanical energy. This ability to generate mechanical forces internally, in the bulk, is what allows the drop to move without exerting forces at its boundaries (the walls).

Dr Loisy added: "A drop of active matter moving through tiny gaps is a minimal model to understand cell motility in tissues, which are crowded environments with intricate geometries.

"The mechanism we discovered provides a possible explanation to the open question of how cells move in those environments. Such motility is crucial to a multitude of physiological processes in living organisms, including immune response and wound healing, and its deregulation is key to cancer dissemination (metastasis)."

The next step is to observe this phenomenon experimentally, using a drop of cell extracts in a specifically engineered microchannel.

(Boston)--African-Americans are at higher risk for cancer-associated venous thromboembolism (VTE) as compared with patients from other races.

VTE is a condition in which a blood clot forms in a vein and then dislodges to travel in the bloodstream. In the U.S., VTE is responsible for an estimated 300,000 deaths annually and an estimated 20 percent of these deaths occur among patients with cancer. Several studies have shown that patients with cancer are at a significantly increased risk of developing VTE, yet the in?uence of race on cancer-associated VTE remains unexplored until now.

Researchers from Boston University School of Medicine (BUSM) identi?ed 16,498 subjects with organ and hematologic cancers from 2004 to 2018. Among this group they identified 186 VTE cases, of which the majority of the events occurred within the ?rst two years of cancer diagnosis. Overall, African American patients showed a three times higher incidence of VTE compared with Caucasian patients. This difference was observed in certain cancer types such as lung, gastric (stomach) and colorectal. In lung cancer, the odds of developing VTE in African American patients was 2.77-times greater than those in white patients.

Studies have shown that VTE is the second most common cause of non-cancer related deaths in patients with cancer and is a significant predictor of decreased survival during the first year for all cancer types. However, current models for predicting a patient's risk of developing VTE do not factor in race and, as such, are likely incomplete and inaccurate.

The BUSM researchers believe that this study has implications for creating new tools that integrate race as a risk factor to help clinicians more accurately predict the risk for developing VTE in patients with cancer. "The integration of race into treatment algorithms for anticoagulation in cancer patients may further optimize risk-predictive models and more accurately stratify the risk of cancer-associated VTE," explained by corresponding author Vipul Chitalia, MD, PhD, associate professor of medicine at BUSM.

Exposure to underwater pile driving noise, which can be associated with the construction of docks, piers, and offshore wind farms, causes squid to exhibit strong alarm behaviors, according to a study by Woods Hole Oceanographic Institution (WHOI) researchers published Dec. 16, 2019, in the journal Marine Pollution Bulletin.

"This study is the first to report behavioral effects of pile driving noise on any cephalopod, a group including squid, cuttlefish, and octopuses," says lead author Ian Jones, a student in the Massachusetts Institute of Technology-Woods Hole Oceanographic Institution Joint Program in Oceanography.

Squid use natural alarm and defense behaviors like inking, jetting, and changing color and patterns on their skin for communication and also for survival when they're trying to avoid capture. Squids' changeable skin gives them the ability to create extraordinary camouflage, enabling them to blend into the background and avoid becoming a meal.

Jones and his colleagues in the Sensory Ecology and Bioacoustics Lab at WHOI exposed longfin squid (Doryteuthis pealeii) to pile driving sounds originally recorded near the construction site of the Block Island Wind Farm in Rhode Island. The squid exhibited the same types of natural alarm and defense behaviors when they were exposed to the noises, but it's what they did next that surprised the researcher team.

"The alarm behaviors occurred within the first several noise impulses, but they diminished quickly within the first minute of playback," Jones says. "That suggests a learned lack of response to the noise, as the squid perceive the noise stimulus may not pose an immediate threat, unlike the imminent threat of a nearby predator. This phenomenon is called habituation."

Following a 24-hour rest period, the research team exposed the squid again. The squid exhibited similar responses and habituation rates, indicating that they had once again become sensitized to the noise.

"It was surprising that they basically showed the same responses on day two," says WHOI biologist Aran Mooney, a coauthor and Jones' advisor. "It was like the squid forgot the noise treatment from one day to the next, despite their super strong initial reactions. That kind of diminishing physiological or behavioral response to a noise may increase squids' susceptibility to predators."

In the next decade, the offshore wind industry is expected to expand rapidly in the Northeast U.S., causing concern among federal entities and commercial fishermen over how the behavior of commercially important fish and other species will be impacted.

Squid play a key role in the marine food web. Many marine mammals, seabirds, and fish feed off squid, as well as humans, who eat about three million metric tons of squid annually.

The results of the study could help management agencies and those in the offshore wind industry minimize disruptions to important fishery species like squid. The squid fishery on the east coast is valued at about 40 million dollars per year.

"Our results suggest that using longer periods between pile driving activity may discourage this type of long-term habituation, meaning squid will be more likely to respond to the noise with these alarm responses, and possibly more likely to successfully avoid predators with these responses as well," Jones says. "This study has given us a first look at how human-made noise can influence natural, ecologically important behaviors of these squid, and we still have much to learn about how these behavioral changes might influence squids' interactions with predators and with other squid".

Key takeaways:

Squid exhibit anti-predator defense behaviors at the onset of pile driving noise playback.

Fast habituation (a decrease in response to a repeated stimuli) may make squid more vulnerable to predation.

Response and habituation rates are similar for second exposures after 24-hour rest period.

Longer periods between pile driving activity may discourage long-term habituation.

Squids' alarm responses to pile driving noises suggest a disruption to their essential communication behaviors.

Polymers are used to develop various materials, such as plastics, nylons, and rubbers. In their most basic form, they are made up of many of identical molecules joined together over and over, like a chain. If you engineer molecules to join together in specific ways, you can control the characteristics of the resulting polymer.

Using this method, Sheng Shen, an associate professor of mechanical engineering at Carnegie Mellon University, and his research team created a polymer thermal regulator that can quickly transform from a conductor to an insulator, and back again. When it's a conductor, heat transfers quickly. When it's an insulator, heat transfer much more slowly. By switching between the two states, the thermal regulator can control its own temperature, as well as the temperature of its surroundings, such as a refrigerator or computer.

In order to switch between high to low conductivity, the very structure of the polymer has to change. This transformation is activated solely with heat. The polymer starts "with a highly-ordered crystalline structure," Shen said. "But once you increase the temperature of the polymer fiber, to around 340 Kelvin, then the molecular structure changes and becomes hexagonal."

The findings were published in Science Advances in a paper titled, "High-Contrast and Reversible Polymer Thermal Regulator by Structural Phase Transition." Collaborators included Carnegie Mellon's Michael Bockstaller, Renkun Chen of the University of California-San Diego, Sukwon Choi of the Pennsylvania State University, Kedar Hippalgaonkar of the Agency for Science Technology and Research (Singapore), and Tengfei Luo of the University of Notre Dame.

The transformation occurs because the heat targets the molecular bonds. "The bonding of the molecules becomes pretty weak," Shen said. "So the segments can rotate." And once the segments rotate, the structure becomes disordered, greatly reducing its thermal conductivity. This type of transition is known as a solid-solid transition; although the polymer reaches temperatures close to its melting point, it remains a solid through the process.

When studying the polymer's transformation, Shen concentrated his data on how its conductivity changed. He also gathered data on other phase transitions so he could compare the ratios. "When you look at all the materials we have on Earth, the conductivity change is, at most, a factor of four," Shen says. "Here, we've already discovered a new material that can have a conductivity change of around ten."

Additionally, the structural change can happen quickly, within a range of five Kelvin. It's also reversible, which allows it to be turned on and off like a switch. It can handle much higher temperatures than other thermal regulators, remaining stable up to 560 Kelvin. It's hard to break down, so it can survive many transitions. And since it's heat-based, it doesn't use as many moving parts as typical cooling methods, making it much more efficient.

While this research has been explored theoretically in the past, Shen's work is the first time it's been shown experimentally. Shen believes that the polymer will have real-world applications. "This control of heat flow at the nanoscale opens up new possibilities," said Shen, "Such as developing switchable thermal devices, solid-state refrigeration, waste heat scavenging, thermal circuits, and computing."

This work builds on previous research in Shen's lab, where his team had developed a polymer nanofiber that was strong, lightweight, thermally conductive, electrically insulating, and bio-compatible--all at less than 100 nanometers wide.

Ewing sarcoma, an aggressive tumor that commonly affects bones in adolescents and young adults, is diagnosed in about 225 American children and teens every year, accounting for about 1 percent of pediatric cancers. Although Ewing sarcoma has been studied for decades, it has no effective cure and a survival rate of just 20-30% for patients who relapse; furthermore, most treatment require surgical resections or amputation and this impacts quality of life of the patients. But a research team at Houston Methodist aims to change those odds.

A new possibility for treatment is proposed by Stephen Wong, Ph.D., John S. Dunn Sr. Presidential Distinguished Chair in Biomedical Engineering and professor of computer science and bioengineering in oncology at Houston Methodist. He is proposing a combination of two well-known drugs as a new treatment option for Ewing sarcoma--the chemo drug imatinib and the diabetes drug metformin.

ITHACA, N.Y. - In the not-so-distant future, city streets could be flooded with autonomous vehicles. Self-driving cars can move faster and travel closer together, allowing more of them to fit on the road - potentially leading to congestion and gridlock on city streets.

A new study by Cornell researchers developed a first-of-its-kind model to control traffic and intersections in order to increase car capacity on urban streets, reduce congestion and minimize accidents.

"For the future of mobility, so much attention has been paid to autonomous cars," said Oliver Gao, professor of civil and environmental engineering and senior author of the study, which published in Transportation Research Part B.

"If you have all these autonomous cars on the road, you'll see that our roads and our intersections could become the limiting factor," Gao said. "In this paper we look at the interaction between autonomous cars and our infrastructure on the ground so we can unlock the real capacity of autonomous transportation."

The researchers' model allows groups of autonomous cars, known as platoons, to pass through one-way intersections without waiting, and the results of a microsimulation showed it increased the capacity of vehicles on city streets up to 138% over a conventional traffic signal system, according to the study. The model assumes only autonomous cars are on the road; Gao's team is addressing situations with a combination of autonomous and human-driven cars in future research.

Car manufacturers and researchers around the world are developing prototypes of self-driving cars, which are expected to be introduced by 2025. But until now, little research has focused on the infrastructure that will support these driverless cars.

Autonomous vehicles will be able to communicate with each other, offering opportunities for coordination and efficiency. The researchers' model takes advantage of this capability, as well as smart infrastructure, in order to optimize traffic so cars can pass quickly and safely through intersections.

"Instead of having a fixed green or red light at the intersection, these cycles can be adjusted dynamically," Gao said. "And this control can be adjusted to allow for platoons of cars to pass."

Cancer development is associated with the gradual accumulation of DNA defects over time. Thus, cancer is considered an age-related disease. But why do children develop cancer? An international team of researchers, led by Charité - Universitätsmedizin Berlin and the Memorial Sloan Kettering Cancer Center in New York, now reveal that mysterious rings of DNA known as extrachromosomal circular DNA can contribute to cancer development in children. Producing the first detailed map of circular DNA, the scientists have shed new unanticipated insights on long standing questions in the field of cancer genetics. The work has been published in Nature Genetics*.

Every year, nearly half a million people in Germany develop cancer. Approximately 2,100 cancer patients are children under the age of 18. The fact that the majority of cancers develop in old adults is due to the mechanisms contributing to cancer development. A range of exogenous factors, including tobacco smoke and radiation, can cause damage to cellular DNA. If this type of DNA damage is left to accumulate over many years, affected cells may lose control over cell division and growth. This results in cancer development. Children, however, are not old enough to be affected by this mechanism of cancer development. What, then, is the reason for childhood cancers? A team of researchers, led by Dr. Anton Henssen of Charité's Department of Pediatrics, Division of Oncology and Hematology and the Experimental and Clinical Research Center (ECRC,) an institution jointly operated by Charité and the Max Delbrück Center for Molecular Medicine (MDC), are a large step closer to finding an answer. Working alongside a team of scientists led by Dr. Richard Koche from the Memorial Sloan Kettering Cancer Center and other international partners, the groups of researchers were able to show that rings of DNA can cause disruption of our cells' genetic information, which can contribute to cancer development.

Scientists have known about these ring-shaped sections of DNA for decades. Found inside our cells, they do not form part of our normal genetic information, which is stored in the form of chromosomes. It is for this reason that they are referred to as extrachromosomal circular DNA. But even nowadays, scientists know relatively little about their function, mainly because they have lacked technologies for a more detailed analysis of circular DNA. In their now published study, the researchers combined state-of-the-art sequencing techniques with pioneering bioinformatics algorithms to perform the first-ever detailed mapping of circular DNA in neuroblastoma, a deadly childhood tumor . Based on their findings, the researchers were able to draw important conclusions regarding the development of this type of cancer.

Working with colleagues from the Barcelona Supercomputing Center, the researchers analyzed neuroblastoma tissue samples from a total of 93 children. Their analysis revealed that the prevalence and diversity of circular DNA is far greater than previously anticipated. According to the researchers' findings, each tissue sample contained on average 5,000 circular DNA copies. DNA sequencing also revealed the process by which specific DNA sections separate from a chromosome to form circular DNA before reintegrating into the chromosome at a different location. "This can potentially cause cancer if it results in the original sequence of genetic information being disrupted," explains the Emmy Noether Independent Junior Research Group's leader, Dr. Henssen, who is also a researcher at the German Cancer Consortium (DKTK) in Berlin and a Berlin Institute of Health (BIH) Clinician Scientist. Stressing the significance of the researchers' findings, Dr. Henssen says: "The detailed processes involved had not previously been elucidated in this manner and provide insight into how even young cells, like those found in children, can transform into cancer cells."

"We were also able to show that certain types of circular DNA may accelerate neuroblastoma growth," explains Dr. Koche and adds: "Testing for their presence may therefore make it easier to predict the course of the disease. Additionally, studying this process in the relatively quiet genomes of these pediatric tumors may help illuminate similar mechanisms which were previously missed in more complex adult cancers. Given the recent interest in circular DNA in a variety of normal and disease contexts, the current study may have implications for a broad range of tumor types and associated clinical outcomes."

The research groups plan to conduct a follow-up study to verify the diagnostic validity of circular DNA. "We also want to conduct more detailed research into the origins of circular DNA in order to better understand why it is that children develop cancer," says Dr. Henssen.

Washington, DC-- Every school child learns about the water cycle--evaporation, condensation, precipitation, and collection. But what if there were a deep Earth component of this process happening on geologic timescales that makes our planet ideal for sustaining life as we know it?

New work published in the Proceedings of the National Academy of Sciences by Carnegie's Yanhao Lin and Michael Walter--along with former Carnegie scientists and ongoing collaborators Ho-Kwang "Dave" Mao and Qingyang Hu of the Center for High Pressure Science and Technology Advanced Research Shanghai and Yue Meng of Argonne National Laboratory--demonstrates that a key mineral called stishovite is capable of storing and transporting large amounts of water even under extreme conditions like those found in Earth's lower mantle.

This is important, because it shows that substantial quantities of water could be present farther into the mantle than previously thought, indicating that a whole-mantle water cycle is possible.

"To get down into the mantle, water must be incorporated into minerals on the surface and then be stably maintained in those structures under the conditions found deep inside the planet," explained lead author Lin.

The researchers used lab-based mimicry to study the mineral stishovite, which is a high-pressure form of quartz, when it's with water under high pressure and temperature conditions. We already know substantial amounts of water can be stored in silicate minerals in the Earth's upper mantle, which exists between 100 and 670 kilometers (or 62 to 416 miles) deep. But the team examined stishovite and water under simulated conditions like those found deep in the lower mantle, which exists between 670 and 2,900 kilometers (or 416 to 1,802 miles) down, where it was thought that much less water could be stably stored in minerals.

"Stishovite is a silica-based mineral and a major component of the oceanic crust." explained Mao. "In plate tectonics, there are areas called subduction zones where an oceanic plate slides beneath a continental plate, sinking from the Earth's surface into its depths. When this happens, stishovite is transported into the mantle."

The discovery of diamonds with water-containing mineral inclusions that come from depths to about 700 kilometers (or 535 miles) down in the mantle revealed that water indeed gets at least that far down if it finds the right mineral with which to hitch a ride.

Stishovite is one such mineral, but is it capable of taking water even deeper, down into the lower mantle? This is what the researchers set out to discover.

They subjected tiny samples of stishovite with water to a range of about 320,000 to 510,000 times normal atmospheric pressure and heated it to a range of about 1,000 to 1,500 degrees Celsius simulating a gradient transiting from upper mantle conditions to lower mantle conditions. Remarkably, they found that stishovite can accommodate large amounts water even under these conditions.

"If water can be stored in minerals at lower mantle pressures and temperatures, it could indicate that there is a global water cycle occurring on very long geologic time scales," explained Walter. "This could alter our understanding of how deep planetary interiors may influence or control the water content at the surface."

You might think that prey would invariably flee in terror from a predator. But what if an animal was apathetic in the face of danger?

A new study in Frontiers in Ecology and Evolution investigates why some moths are more relaxed fliers in the face of bat attacks. The research reveals that less appetizing moths are more nonchalant when attacked by bats, whereas more palatable moths tend to employ evasive maneuvers.

The work demonstrates the complex risks and rewards of anti-predator strategies where mistakes invariably mean death, and may let scientists predict the evasive behaviors of rare or even extinct species.

Many prey animals have evolved defense mechanisms to evade and deter potential predators. In moths, these include chemical defenses that make them less appetizing, ultrasonic hearing to hear bats coming, and mid-flight evasive maneuvers -- such as swoops and dives -- that help them to escape.

However, researchers understand relatively little about how these factors are linked and how they vary between different species. Dr. Nicolas Dowdy of the Milwaukee Public Museum and Wake Forest University in the US, noticed unusual behavior in certain species of tiger moths, which seemed to be relatively relaxed when attacked by predatory bats.

Intrigued by this behavior, Dowdy and his colleagues set out to identify the factors that contribute to this apparent nonchalance. They hypothesized that nonchalant moths have evolved chemical defenses that made them unpalatable, meaning they have less motivation to evade bats than their more delicious moth counterparts.

Why not just evade the bats anyway? Well, there are risks and rewards for specific anti-predator strategies. For instance, performing panicked evasive maneuvers might help a moth avoid a bat, but it might also land it in a spider's web or away from a food source or mate (in addition to being pretty exhausting). Dowdy speculated that unappetizing moths may often take the lazier and potentially safer option by relying on their chemical defenses rather than roll the dice on an emergency flight.

To test his hypothesis, Dowdy and his colleagues collected five different species of tiger moths and then released them in an outdoor "flight arena" at night, where wild bats would frequently swoop in to feed. Using infrared cameras, the team monitored interactions between the bats and moths and recorded how often different species displayed evasive or nonchalant behavior during a bat attack. They also measured how palatable the moths were to the bats by observing if the bats consumed the moths or spat them out.

"Strikingly, we observed that moths with weak or no chemical defenses often dive away to escape bat attacks," explained Dowdy. "However, moths with more potent chemical defenses are more 'nonchalant', performing evasive maneuvers less often."

This correlation allowed the researchers to predict the evasive or nonchalant behavior of the moths based on their palatability. It may be possible that this relationship between palatability and nonchalance exists elsewhere in the animal kingdom but future studies are needed.

An exciting extension of this work may be reconstructing behaviors of rare or even extinct species. By measuring levels of unappetizing compounds in preserved animal specimens as an estimate of a species' palatability, it could be possible to deduce whether or not these extinct creatures would have actively evaded predators or been more casual in their defensive behaviors.

At least there's a silver lining for disgusting moths: being repulsive means that you can rest a little easier in the face of danger.

Black teenagers experience daily racial discrimination, most frequently online, which can lead to negative mental health effects, according to a Rutgers researcher.

The study, published in the Journal of Applied Developmental Psychology, examined how often black teens experience racial discrimination each day - either personally or vicariously and online or offline.

The researchers surveyed 101 black youth between ages 13 and 17 from predominantly black neighborhoods in Washington, D.C., each day for two weeks about their experiences with racial discrimination and measured changes in their depressive symptoms across that period.

The teens reported more than 5,600 experiences of racial discrimination in total - an average of more than five experiences per day.

"This research reflects what researchers and activists have asserted for years: Black adolescents are forced to face antiblack microaggressions on a daily basis. Importantly, this study expands the research on the many ways that discrimination happens, whether it is being teased by peers, asked to speak for their racial group in class or seeing a racist post on social media," said lead author Devin English, an assistant professor at Rutgers School of Public Health.

The experiences reported in the study, which ranged from teasing about physical appearance to overt discrimination, mainly occurred online and led to short-term increases in depressive symptoms. Examples of discrimination included teasing by peers about wearing their hair natural, seeing jokes about their race online and witnessing a family member or friend being treated poorly due to their race or ethnicity.

"Racial teasing is important because it is one of the most common ways adolescents communicate about race," English noted. "Critically, young people and adults, such as teachers, often see this teasing as harmless and choose not to address it. Our results, however, show several types of racial teasing are harmful for black adolescents."

"Although public discourse can indirectly or directly blame health inequities on black youth, our study provides evidence that racial discrimination in society is a fundamental cause of these health inequities," he continued. "Knowing this, people in positions of power such as clinicians, school administrators and policy makers have a responsibility to consider discrimination as a critical aspect of the daily experience and health of black teens. Racial discrimination prevention should be a public health imperative."

Some of the most well-known literary works were left unfinished when the authors died, masterpieces like The Trial by Franz Kafka, Maria or The Wrongs of Woman by Mary Wollstonecraft and The Canterbury Tales by Geoffrey Chaucer.

The unfinished manuscript of the opening chapter of what would have been the novel "Sapphira Wade" may be such a work for acclaimed contemporary American author Gloria Naylor who died in 2016 at the age of 66. The authors of a new paper about the manuscript included among Naylor's collected papers have transcribed the handwritten document for the first time.

Best known for her 1982 National Book Award-winning novel The Women of Brewster Place — which was adapted into a beloved TV miniseries that was produced by and starring Oprah Winfrey — Naylor stands among the most influential contemporary American authors. She authored numerous novels illuminating aspects of the experiences of African Americans, particularly African American women, including Linden Hills, Bailey's Cafe and Mama Day.

There is evidence that Naylor hoped for "Sapphira Wade" to be a capstone of her literary career, report researchers Suzanne M. Edwards, Associate Professor of English at Lehigh University and Trudier Harris, University Distinguished Research Professor of English at The University of Alabama in an upcoming paper. In the paper, Edwards and Harris write about Naylor's plans for "Sapphira Wade" gleaned from the author's notes, interviews and personal correspondence and, for the first time, publish excerpts from Naylor's 131-page manuscript. The paper, titled "Gloria Naylor's 'Sapphira Wade': An Unfinished Manuscript from the Archive," was just published online and appears in the winter issue of African American Review. The complete manuscript of "Sapphira Wade" is currently being digitized and will be available through the author's archive in 2020.

"Perhaps the most striking feature of the material in the archive is that Naylor wrote privately about Sapphira Wade across more than twenty years," said Edwards, who is also Director of the Humanities Center and core faculty in Women's, Gender, and Sexuality Studies at Lehigh.

Sapphira Wade is a character in Naylor's acclaimed 1988 novel Mama Day. She is the great-grandmother of the novel's title character. Mama Day, the matriarch of the fictional community of Willow Springs, an island off the coasts of Georgia and South Carolina. In the novel, Sapphira's life is both legendary and mysterious to her ancestors on the island. She is known to have been sold to Bascombe Wade in 1819 and, in some unknown way, to have gained the deed to Willow Springs from him before he died in 1823. It is at that point that the island became an autonomous community of free African Americans during the pre-Civil War era. The manuscript represents the planned novel's opening chapter and details the early life of Bascombe Wade in Norway, from his birth to his departure for England with plans to travel to India as a Christian missionary.

According to Edwards and Harris, Naylor said in a 2000 interview that her intention for the novel "Sapphira Wade" was to tell the story leading up to Sapphira's acquisition of the land following Wade's journey from Norway in the 19th century and Sapphira's journey from Senegal leading up to their meeting in Savannah, Georgia.

About the unfinished manuscript, the authors write: "How that 35,000-word narrative, dated 2006, may have connected to the events of 1823, when 'a man named Bascombe Wade sectioned up the island and deeded the entire thing to the black people who were [there] with him,' remains unknown..."

Though scholars and readers may be disappointed to find that the character Sapphira Wade does not appear in the manuscript's pages, the authors note: "Naylor's published interviews as well as the letters, journal entries, and research materials in the archive at Sacred Heart University offer some hints about 'Sapphira Wade' beyond Bascombe's story."

Still, says Edwards, while what is missing from the manuscript is striking, what the manuscript does contain is also striking.

"The narrative covers almost 20 years of Bascombe Wade's life and fleshes out a character from Mama Day in unexpected ways," says Edwards. "We are introduced to a man who crosses cultural, linguistic, and religious barriers between a Norwegian island settlement and the indigenous, nomadic Sami before journeying to the urban center of Trondheim on his way to missionary work abroad."

"After completing her book tour for Bailey's Cafe in 1992," write the authors, "Naylor turned her attention to 'Sapphira Wade' which she anticipated would be her next novel. In a letter dated June 1, 1993 she speaks to her research agenda: 'I'm going to Africa in July--Ivory Coast, Senegal, and Gambia to attend a writer's conference and then to travel a bit with research for my new novel, Sapphira Wade' (Personal correspondence). Over the years, Naylor took more trips to Africa and Norway as part of her 'intensive research' for the novel: 'I had to physically go to the place in order to walk the terra firma...to breathe the air with this novel'..."

The manuscript, they write, "...stands as a monument to a mysterious, restless genius who traveled halfway around the world to ensure that her conception of a character and his origins was as substantive as history and culture would allow."

Sapphira Wade was Naylor's "muse"

Though the manuscript is dated 2006, Edwards and Harris note that the earliest reference to "Sapphira Wade" among Naylor's papers is in a journal entry from 1981, when Naylor was a master's degree student at Yale University. In it, Naylor ruminates about the future, writing: "...After Willie and Lester will come Mom Day and somewhere after her Sapphira. And probably many more in between..."

In a 2006 letter to author Julia Alvarez, Naylor refers to Sapphira as her "muse" and alludes to why she may have put the writing of the novel aside, writing: "I have lived with this story a long time. This woman's face first came to me when I was working the midnight shift on a hotel switchboard back in the late 70s. I drew it and put it away, knowing that she was my muse. I believe that she has guided me all these years; protected me when I couldn't protect myself. And I have tried to protect her: that's why I put away all of my material in 1996 and wrote the Men of Brewster Place..."

Naylor wrote at length about Sapphira in the 2006 letter to Alvarez, write Edwards and Harris: "Describing her sense of obligation to the character, Naylor explains that she could not begin to write Sapphira's story without first restoring her own 'sense of self' after the challenges detailed in 1996: 'She deserved to have her story told in language that was the best I could find.' Poetry, Naylor enthuses, has allowed her to begin access to that language..."

Naylor refers to a series of poems she has been crafting that could assist her in accessing that language and concludes, "[F]or now, I'm living one of the lines of my poem":

A woman must tell stories
To save her life (Letter to Alvarez)"

Though the manuscript and the archives do not answer the question of how the white slave-owner Bascombe Wade — born a "bastard" and fathered by "God" — and the enslaved Sapphira came together and how the land was eventually deeded to her, it does offer biographical details of Bascombe Wade that serve to humanize him for readers.

Edwards and Harris write: "In 'Sapphira Wade,' Naylor eschews the Africa-to-North America pathway and invites readers to consider a different kind of potential slaveholder. Certainly, African American narrators occasionally mention English or Irish slaveholders in their narratives, but there is no information about how those foreigners were developed socially and culturally or how they came to enslave human beings. With Bascombe Wade, Naylor makes clear that he is simply a boy and a man, shaped by his illegitimate status (which might influence his nonslaveholding attitude as well), and who exhibits limited interest in politics or the social conditions of Norway beyond what affects his village...As Bascombe embarks on the trip to England, he is essentially a clean political and social slate on which the requirements for practicing slavery would have to be written (if that were possible). At this point, however, he is a likeable, talented young man with whom readers sympathize without qualification"

The archive does contain some clues about Naylor's plans to explain how Bascombe Wade and Sapphira meet. Still, the details surrounding Sapphira Wade's history remain mysterious. Edwards and Harris reveal that the archives contain some written fragments that apply more directly to Sapphira, including these sentences: "Sapphira accepted that she loved this man. The moonlight that coated the wisps of his golden hair. The thin line that ran down the outer edge of the lips that caressed her neck. And she accepted the dagger that lay under her pillow which she could reach back and stiffen his life's blood with. Sapphira had arrived"

Despite the absence of the completed version, the authors conclude that "... 'Sapphira Wade' succeeds in a crucial way. It extends the respect that Gloria Naylor has earned as an artist who was devoted unconditionally to her craft, who produced solid work, and who challenged herself down to the minutiae of that creativity."

Naylor's collected papers offer insight into the process of this influential author who wrote in a 1981 journal entry, prophetically given the unfinished work she left behind: "...I will die with a pen in my hand."

By tracking the motions of cold atom clouds, astronomers can learn much about the physical processes which play out in the depths of space. To make these measurements, researchers currently use instruments named 'cold atom inertial sensors' which, so far, have largely been operated inside the lab. In new work published in EPJ D, a team of physicists at Muquans and LNE-SYRTE (the French national metrology laboratory for time, frequency and gravimetry) present an innovative prototype for a new industrial laser system. Their design paves the way for the development of cold atom inertial sensors in space.

The insights gathered by the team could offer significant improvements in the accuracy of tests of fundamental physics, as well as assessments of the Earth's gravitational field. Studies in the past have made significant strides towards mobile laser systems for cold atom inertial sensing which are more compact, but these have not yet widely proven suitable for measurements in space. In their study, the researchers' updated laser system was implemented onto a ground-based atomic sensor at LNE-SYRTE. This enabled them to prove that their prototype was ready to carry out real experiments measuring the subtle variations in the Earth's gravitational field using matter wave interferometry techniques. Their work was carried out in collaboration with Sodern in the frame of a more general study led by the European Space Agency (ESA), whose objective was to assess and improve the maturity of cold atom technologies.

The design involves industrial lasers which are typically used for telecommunications; with their frequencies doubled. This setup benefited from a wide availability of components, as well as extensive previous research into the properties of the lasers. Through further testing in space-like environments, the team hopes that their system could soon allow researchers to probe various aspects of the physical environment of space in unprecedented levels of detail.

The fragmentation of natural habitats by fences and human settlements is threatening the survival of the white rhinoceros. It prevents dispersal from the family group and leads to mating among close relatives. Additionally female rhinoceros favour individual males for mating over others and sire several offspring with the same partner over consecutive breeding periods. These factors lead to a high degree of inbreeding. The results come from the largest scientific study to date on the sexual preferences of white rhinos, published in the journal "Evolutionary Applications". The scientists propose specific measures to ensure the long term survival of the species.

Understanding sexual behaviour and mate choice is important for optimising conservation efforts of white rhinos. During the colonial period, intense hunting decimated white rhinos to a few individuals. All currently living white rhinos originate from this small founder population. As a consequence, all white rhinos are depauperate in terms of their genetic diversity. The findings of this new scientific study suggest that the unusual mating behaviour of the white rhinos encourages the loss of genetic diversity. "We need to keep the white rhinos as genetically diverse as possible, if we want to give them a chance to adapt to anthropogenic challenges such as poaching, climate change or diseases", explains Dr Petra Kretzschmar, the leading author of the study and a scientist at the Leibniz Institute for Zoo and Wildlife Research (Leibniz-IZW).

The scientists were surprised by their findings. They did not expect females to keep mating with the same male for several reproductive cycles because long-term bonds with mating partners were previously unknown for rhinos. "They live on their own and only get together shortly before mating," says Dr Kretzschmar. "This is why it took us 13 years of field research to uncover the secrets of their mating behaviour", she continues. The combination of field data with the genetic analysis of paternity of 172 individuals identified three aspects of the mating behaviour of white rhinos that encourage the loss of genetic diversity. Many females stick to the same partner over several consecutive breeding periods, so all their offspring inherit genes from the same father. Moreover, rhinos do not avoid reproducing with family members, as known for many other species. Finally, the reproductive success of males is very unequal, so that a few males dominate the gene pool in the next generation.

In the past, this mating behaviour was presumably not problematic because rhinos were able to leave the home ranges of their mothers and were thus not living near family members. "Today, all remaining rhinos live in modestly sized conservation areas and private game reserves surrounded by fences or human settlements. They cannot disperse far enough to avoid inbreeding," comments Dr Alexandre Courtiol, senior author of the study. The researchers therefore recommend permanent monitoring of offspring and their genetic relatedness to rhinos nearby and a regular exchange of unrelated animals between protected areas. "This is the only way to preserve the long-term genetic heritage of the species," concludes Dr Kretzschmar.