Culture

Pierfranco Demontis said in 1988, "Ice becomes a fast-ion conductor at high pressure and high temperatures," but his prediction was only hypothetical until recently. After 30 years of study, superionic water ice was verified experimentally in 2018. Superionicity may eventually explain the strong magnetic field in giant planetary interiors.

What about Earth, whose interiors are also under extreme pressure and temperature conditions? Although three-quarters of Earth's surface is covered by water, standalone water or ice rarely exists in Earth's interiors. The most common unit of "water" is hydroxyl, which is associated with host minerals to make them hydrous minerals. Here, a research group led by Dr. Qingyang Hu, Dr. Duckyoung Kim, and Dr. Jin Liu from the Center for High Pressure Science and Technology Advanced Research discovered that one such hydrous mineral also enters an exotic superionic phase, similar to water ice in giant planets. The results are published in Nature Geosciences.

"In superionic water, hydrogen will get released from oxygen and become liquid-like, and move freely within the solid oxygen lattice. Similarly, we studied a hydrous mineral iron oxide-hydroxide (FeOOH), and the hydrogen atoms move freely in the solid oxygen lattice of FeO2," said Dr. He, who conducted the computational simulation.

"It developed into the superionic phase above about 1700°C and 800,000 times normal atmospheric pressure. Such pressure and temperature conditions ensure a large portion of Earth's lower mantle can host the superionic hydrous mineral. These deep regions may have rivers made of protons, which flow through the solids." added Dr. Kim.

Guided by their theoretical predictions, the team then tried to verify this predicted superionic phase in hot FeOOH by carrying out high-temperature and high-pressure experiments using a laser-heating technique in a diamond anvil cell.

"It is technically challenging to recognize the motion of H atoms experimentally; however, the evolution of O-H bonding is sensitive to Raman spectroscopy," said Dr. Hu, one of the lead-authors. "So, we tracked the evolution of the O-H bond and captured this exotic state in its ordinary form."

They found that the O-H bonding softens abruptly above 73,000 times normal atmospheric pressure, along with ~ 55% weakening of the O-H Raman peak intensity. These results indicate that some H+ may be delocalized from oxygen and become mobile, thus, weakening the O-H bonding, consistent with simulations. "The softening and weakening of the O-H bonding at high-pressure and room-temperature conditions can only be regarded as a precursor of the superionic state because high temperature is required to increase the mobility beyond the unit cell," explained Dr. Hou.

In superionic materials, there will be an obvious conductivity change, which is robust evidence of superionization. The team measured the electrical-conductivity evolution of the sample at high-temperature and pressure conditions. They observed an abrupt increase in electrical conductivity around 1500-1700°C and 121,000 times normal atmospheric pressure, indicating the diffusive hydrogen had covered the entire solid sample and thus, entered a superionic state.

"The pyrite-type FeO2Hx is just the first example of superionic phases in the deep lower mantle," remarked Dr. Liu, a co-lead author of the work. "It is very likely that hydrogen in the recently-discovered dense hydrogen-bearing oxides that are stable under the deep lower mantle's high P-T conditions, such as dense hydrous phases, may also exhibit superionic behavior."

Women are largely being excluded from decisions about conservation and natural resources, with potentially detrimental effects on conservation efforts globally, according to research.

A University of Queensland and Nature Conservancy study reviewed a swathe of published conservation science, investigating the cause and impact of gender imbalance in the field.

UQ PhD candidate and Nature Conservancy Director of Conservation in Melanesia Robyn James said it was no secret that females were underrepresented in conservation science.

"In fact, according to a recent analysis of 1051 individual top?publishing authors in ecology, evolution and conservation research, only 11 per cent were women," Ms James said.

"We analysed more than 230 peer-reviewed articles attempting to address this very problem, confirming an uncomfortable truth: women's voices are critically lacking in conservation.

"We found that gender discrimination is systemic and consistent, from small and remote communities in places such as the Solomon Islands to large conservation and natural resource management organisations, where women are still underrepresented in leadership and decision-making positions.

"And this seemingly impacts conservation outcomes directly.

"Ten of the reviewed studies investigated the relationship between women's involvement and conservation success - all found explicitly measured and demonstrated positive impacts."

Consevation scientist Dr Nathalie Butt said the research revealed that existing gender roles and dynamics limited women over the course of their lifetimes -- with more than one barrier to overcome.

"Firstly, to address this problem, we need to continually challenge the assumption that leadership positions are best held by men," Dr Butt said.

"There's a persistent perception that men should be decision makers and leaders in most contexts, both within conservation organisations and within communities where conservation work is undertaken.

"Without women in scientific research and leadership or decision-making positions, gender-based discrimination and discrepancies are rarely even recognised as a problem to be solved.

"We must also do more research to understand women's aspirations and agency within conservation and natural resource management.

"It's critical to recognise and address the heavier workloads women carry outside the workplace -tasks such as caring and providing for the household - as these were evident in every culture we studied.

"Finally, we need to bridge the lack of understanding of the gendered use of resources, and the different access to resources that men and women often have."

Dr Butt said initial efforts were working to help turn the tide, but much more needed to be done.

"In Papua New Guinea, The Nature Conservancy has partnered with CARE on a gender audit of their conservation program and is working with all staff to undertake gender-based training," she said.

"They've also developed a new program called Mangoro Market Meri, led by co-author Ruth Konia, which is enabling women to lead conservation and economic decisions around mangrove resources in their communities.

"And at UQ, we're signatories to the Athena SWAN Charter - 10 key principles to help advance gender equity, diversity and inclusion.

"It's a start, but there's still a long way to go - this is a global problem - so let's build a more equal planet, while we work to protect it."

One of the world's rarest tree species has been transformed into a sophisticated model that University of Queensland researchers say is the future of plant research.

"Macadamia jansenii is a critically endangered species of macadamia which was only described as a new species in 1991," said Robert Henry, Professor of Innovation at the Queensland Alliance for Agriculture and Food Innovation (QAAFI).

"It grows near Miriam Vale in Queensland and there are only around 100 known trees in existence."

However, with funding from Hort Innovation's Tree Genomics project, and UQ's Genome Innovation Hub Macadamia jansenii has now become the world's most sophisticated plant research model.

Professor Henry said Macadamia jansenii was probably the best studied species on the planet in terms of its genetics.

"Macadamia jansenii has potentially become the model for assembling all future plant genomes," he said.

Professor Henry said the entire jansenii species grows in one small area. "This means we have the potential to study the diversity of the whole species," he said.

"This is unusual, even for rare or endangered plants - it means we can get a lot of information about how rare plant species survive the impact of small population size and the associated genetic bottleneck.

Professor Henry said that particular characteristics of Macadamia jansenii made it useful for improving the technology and methodology for sequencing and assembling plant genomes.

"We investigated the different sequencing technologies, all the different software and algorithms that you can use in genomic sequencing, and then applied each of them to the same sample to find out what worked best," he said.

"It's a long, complex and very expensive process, so we wanted to use the latest technology to improve its efficiency."

The Genome Innovation Hub's Ms Valentine Murigneux analysed the genome sequence and QAAFI researchers then assembled all 14 chromosomes for the species, in collaboration with laboratories in the United States. This work was published in GigaScience.

Professor Henry said the work is of great interest globally.

"High quality genome sequences are proving much more useful than rough draft sequences with less errors and better outcomes for plant breeding," he said.

Macadamia jansenii was first brought to the attention of Western plant scientists in 1983, by Ray Jansen, a canefarmer and skilled amateur botanist from a South Kolan in Central Queensland.

Ms Denise Bond, Executive Officer of the Macadamia Conservation Trust said since 2018 about 60 new mature Macadamia jansenii trees have been located, although a quarter of these were destroyed in the bush fires of 2019.

"We very much welcome the genomic research on Macadamia jansenii as it will help prioritise future conservation efforts, although right now the most critical thing is to protect the remaining wild trees in their original habitat," Ms Bond said.

She said the remaining three macadamias species - M. ternifolia, M. tetraphylla and M. integrifola - were listed on the International Union for Conservation of Nature's Red List of Threatened Species in 2020.

"This is a wake-up call to Australia to take better care of our native macadamia species."

Professor Henry said all four macadamia species - tetraphylla, integrifolia, ternifolia and jansenii have now undergone the same analysis.

"It is fitting this work has been developed in Queensland using the Macadamia genus - one of Australia's few additions to the world's food crops," he said

The macadamia genomic work forms part of a five-year project to develop detailed high quality genome sequencing for five of Australia's key horticultural tree crops - avocado, macadamia, mango, citrus and almond - which account for 80 percent of Australian horticulture tree crop value.

"The macadamia data we have generated has been fed through to a range of projects including research on sustainably intensifying tree crop production and breeding for key commercial attributes in macadamia production," Professor Henry said.

In a perfect world, what you see is what you get. If this were the case, the job of artificial intelligence systems would be refreshingly straightforward.

Take collision avoidance systems in self-driving cars. If visual input to on-board cameras could be trusted entirely, an AI system could directly map that input to an appropriate action -- steer right, steer left, or continue straight -- to avoid hitting a pedestrian that its cameras see in the road.

But what if there's a glitch in the cameras that slightly shifts an image by a few pixels? If the car blindly trusted so-called "adversarial inputs," it might take unnecessary and potentially dangerous action.

A new deep-learning algorithm developed by MIT researchers is designed to help machines navigate in the real, imperfect world, by building a healthy "skepticism" of the measurements and inputs they receive.

The team combined a reinforcement-learning algorithm with a deep neural network, both used separately to train computers in playing video games like Go and chess, to build an approach they call CARRL, for Certified Adversarial Robustness for Deep Reinforcement Learning.

The researchers tested the approach in several scenarios, including a simulated collision-avoidance test and the video game Pong, and found that CARRL performed better -- avoiding collisions and winning more Pong games -- over standard machine-learning techniques, even in the face of uncertain, adversarial inputs.

"You often think of an adversary being someone who's hacking your computer, but it could also just be that your sensors are not great, or your measurements aren't perfect, which is often the case," says Michael Everett, a postdoc in MIT's Department of Aeronautics and Astronautics (AeroAstro). "Our approach helps to account for that imperfection and make a safe decision. In any safety-critical domain, this is an important approach to be thinking about."

Everett is the lead author of a study outlining the new approach, which appears in IEEE's Transactions on Neural Networks and Learning Systems. The study originated from MIT PhD student Björn Lütjens' master's thesis and was advised by MIT AeroAstro Professor Jonathan How.

Possible realities

To make AI systems robust against adversarial inputs, researchers have tried implementing defenses for supervised learning. Traditionally, a neural network is trained to associate specific labels or actions with given inputs. For instance, a neural network that is fed thousands of images labeled as cats, along with images labeled as houses and hot dogs, should correctly label a new image as a cat.

In robust AI systems, the same supervised-learning techniques could be tested with many slightly altered versions of the image. If the network lands on the same label -- cat -- for every image, there's a good chance that, altered or not, the image is indeed of a cat, and the network is robust to any adversarial influence.

But running through every possible image alteration is computationally exhaustive and difficult to apply successfully to time-sensitive tasks such as collision avoidance. Furthermore, existing methods also don't identify what label to use, or what action to take, if the network is less robust and labels some altered cat images as a house or a hotdog.

"In order to use neural networks in safety-critical scenarios, we had to find out how to take real-time decisions based on worst-case assumptions on these possible realities," Lütjens says.

The best reward

The team instead looked to build on reinforcement learning, another form of machine learning that does not require associating labeled inputs with outputs, but rather aims to reinforce certain actions in response to certain inputs, based on a resulting reward. This approach is typically used to train computers to play and win games such as chess and Go.

Reinforcement learning has mostly been applied to situations where inputs are assumed to be true. Everett and his colleagues say they are the first to bring "certifiable robustness" to uncertain, adversarial inputs in reinforcement learning.

Their approach, CARRL, uses an existing deep-reinforcement-learning algorithm to train a deep Q-network, or DQN -- a neural network with multiple layers that ultimately associates an input with a Q value, or level of reward.

The approach takes an input, such as an image with a single dot, and considers an adversarial influence, or a region around the dot where it actually might be instead. Every possible position of the dot within this region is fed through a DQN to find an associated action that would result in the most optimal worst-case reward, based on a technique developed by recent MIT graduate student Tsui-Wei "Lily" Weng PhD '20.

An adversarial world

In tests with the video game Pong, in which two players operate paddles on either side of a screen to pass a ball back and forth, the researchers introduced an "adversary" that pulled the ball slightly further down than it actually was. They found that CARRL won more games than standard techniques, as the adversary's influence grew.

"If we know that a measurement shouldn't be trusted exactly, and the ball could be anywhere within a certain region, then our approach tells the computer that it should put the paddle in the middle of that region, to make sure we hit the ball even in the worst-case deviation," Everett says.

The method was similarly robust in tests of collision avoidance, where the team simulated a blue and an orange agent attempting to switch positions without colliding. As the team perturbed the orange agent's observation of the blue agent's position, CARRL steered the orange agent around the other agent, taking a wider berth as the adversary grew stronger, and the blue agent's position became more uncertain.

There did come a point when CARRL became too conservative, causing the orange agent to assume the other agent could be anywhere in its vicinity, and in response completely avoid its destination. This extreme conservatism is useful, Everett says, because researchers can then use it as a limit to tune the algorithm's robustness. For instance, the algorithm might consider a smaller deviation, or region of uncertainty, that would still allow an agent to achieve a high reward and reach its destination.

In addition to overcoming imperfect sensors, Everett says CARRL may be a start to helping robots safely handle unpredictable interactions in the real world.

"People can be adversarial, like getting in front of a robot to block its sensors, or interacting with them, not necessarily with the best intentions," Everett says. "How can a robot think of all the things people might try to do, and try to avoid them? What sort of adversarial models do we want to defend against? That's something we're thinking about how to do."

Tokyo, Japan - Researchers from Tokyo Metropolitan University have studied the properties of mixtures of silicone-coated "magic sand", a popular kid's toy, and normal sand. Silicone-coated sand particles were found to interact with each other only, and not with other sand particles. The team discovered that adding silicone-coated sand beyond a certain threshold leads to an abrupt change in clustering and rigidity, a simple, useful way to potentially tune the flow of granular materials for industry.

Sand is a fascinating material. It can flow and be poured like a liquid, but retains many of the properties of solids, clogging pipes or forming sand dunes. The behavior of collections of small particles like sand is known as granular physics, and is an immensely important field for the handling and transport of the wide range of granular materials out there like grains, rice, powders, and the vast amounts of sand used in the construction industry.

A key conundrum of this branch of physics is the sheer numbers involved. Grains interact via simple, Newtonian mechanics, but because so many particles are interacting at once, there is an emergent complexity of flow behavior that cannot yet be explained by simple equations. Scientists are thus not only looking for better theoretical models to explain granular behavior, but convenient "model systems" that can be handled and tuned in the lab to give insights into how the microscopic structure of granular materials gives rise to their macroscopic properties.

A team led by Assistant Professor Marie Tani and Professor Rei Kurita of Tokyo Metropolitan University have been studying what happens to sand when sand gets wet. It is well known that beach sand, for example, behaves completely differently; sand castles would be tricky to build when dry! This behavior is largely due to the formation of "bridges" of liquid between particles, known as capillary bridges, strongly tying grains together to form load-bearing structures. However, homogeneous wet sand is notoriously hard to prepare in the lab; it's hard to mix evenly, and dries very quickly. To overcome this issue, they instead used "magic sand," hydrophobic sand particles coated in silicone oil, commonly available as a kid's toy. The team found that not only does "magic sand" strongly attract each other via thin strands of oil, but it completely ignores normal sand, simply bumping into it like dry grains. By mixing "magic sand" and normal sand in different ratios, the team could freely study how wet sand behaves down to even the smallest liquid fractions, where only some grains are connected via capillary bridges.

Using three independent methods involving sieving, measuring density and forming stable mounds of sand, they found that the mechanical properties of the mixture changes drastically when the fraction of magic sand to normal sand exceeds 20%. This agreed with findings from percolation theory, which studies how connections between particles span space without any breakages, letting the sand mixture behave significantly more solid-like and bear its own weight. This behavior is known for polymer gels, and helps unify theoretical approaches applied to completely different materials.

The team's mixtures also provide a convenient material for industry with mechanical properties that can be easily modified. Importantly, the method provides a new, convenient, accurate and informative way to explore granular physics, and may become the new default for scientists in future investigations.

New York, NY (March 5, 2021) - Overweight children who were exposed to lead in utero and during their first weeks of life have the potential for poorer kidney function in adulthood, according to an Icahn School of Medicine at Mount Sinai study published in Environment International in March.

The study found that children with high body mass indexes who had been exposed to lead had lower estimated glomerular filtration rate (eGFR), a measure of how well the kidneys are filtering or cleaning the blood. The researchers measured blood levels during mothers' pregnancy and later measured eGFR levels in the children when they were between 8 and 12 years old.

Decreased kidney function is a driver of hypertension, which is a major risk factor for cardiovascular disease, the leading cause of death in the developed world. Obesity is a well-known risk factor for hypertension and chronic kidney disease, and before now, the convergence of kidney toxicants found in the environment and childhood obesity had not been previously studied.

"This is the first study to assess an association between perinatal lead exposure at multiple times in early life with eGFR measured in preadolescence," said senior author Alison Sanders, PhD, Assistant Professor of Environmental Medicine and Public Health, and Pediatrics, at Icahn Mount Sinai. "Future longitudinal assessments of exposure to kidney toxicants and preadolescent kidney function will improve our understanding of risk factors for kidney impairment and associated comorbidities."

This epidemiological study of Mexican children is ongoing and will follow the children into adolescence. The study was conducted in Mexico because children there are exposed to higher levels of lead and experience higher risk for kidney problems than American children. Additional study is needed to confirm the relevance of these findings in other populations.

Researchers from University of Houston and University of Bochum published a new paper in the Journal of Marketing that examines how variable compensation plans for salespeople can lead to lower health.

The study, forthcoming in the Journal of Marketing, is titled "Variable Compensation and Salesperson Health" and is authored by Johannes Habel, Sascha Alavi, and Kim Linsenmayer.

Sales compensation plans typically comprise a variable component. Variable compensation is issued on top of a base salary and the amount is contingent on performance. For example, a salesperson with an annual target salary of $100,000 and a variable compensation share of 80% would receive $20,000 as a fixed amount with the remaining $80,000 contingent on the achievement of predetermined sales targets. Variable compensation is widely used and accounts for approximately 40% of total sales compensation in the United States--equivalent to more than $320 billion. However, variable compensation can conjure substantial compensation uncertainty for salespeople.

Variable compensation has been frequently shown to motivate salespeople to work harder and thus achieve higher performance. However, this research shows that variable compensation also induces performance pressure, which causes stress, burnout, and sickness. These "hidden costs" of variable compensation directly counter the hoped-for positive effects on performance.

The researchers conducted four studies to investigate this situation. The first study examined a business that reduced the variable share in salespeople's compensation plan from 80% to 20%. After reducing the share, salespeople's sales performance decreased, but interestingly, the number of days salespeople fell sick also decreased, by approximately 30%. Thus, when receiving a higher fixed salary, salespeople worked less hard, but gained health in return.

The second and third studies surveyed salespeople from various companies and industries to better understand the relationship between variable compensation, performance, and health. Results indicate that variable compensation shares lead salespeople to experience increased stress and burnout, particularly if these shares are relatively high (> 30%). However, these experiences strongly depend on the individual salesperson's ability and social resources. First, high ability reduces the uncertainty regarding which compensation the salesperson achieves. Second, salespeople who have social resources in the form of a good relationship with their leaders and teams can cope better with the pressure from variable compensation. Thus, these salespeople experience less stress and burnout (by approximately 15%).

In the fourth study, the researchers examined how managers make decisions about sales team's variable compensation. This study reveals that managers choose lower variable compensation shares if they were made aware of the stress induced by their decisions. These managers were particularly likely to choose lower variable compensation shares if they were empathic. Empathy seems to allow managers to understand and appreciate the hidden costs associated with high levels of stress, such as low staff morale, high absenteeism, and turnover.

As Habel explains, "Based on our findings, we recommend that companies that incentivize their sales teams through variable compensation shares strive to mitigate the potential health problems those incentives create." First, if a company's variable compensation share is high, managers should carefully screen salespeople and sales supervisors before hiring them. Specifically, when hiring salespeople, managers should determine their ability and social resources that will enable them to cope with the stress from variable compensation plans. For example, while interviewing salespeople and reviewing references, managers might probe the stability of their past performance, their experience, and their tendency to build relationships with leaders and peers. If these resources are lacking or unobservable (e.g., for first-time employees), managers might screen for other stress-related resources, such as strong personal resilience or social networks. When hiring sales supervisors, managers also should screen for these applicants' ability to help salespeople cope with stress and the ability to build strong relationships with and among team members.

Second, managers should help salespeople build their job-related resources. For example, by encouraging salespeople to manage their sales pipeline in a way that secures a steady stream of sales, managers can help them reduce compensation uncertainty and thus stress. Regarding social resources, companies should train supervisors to adopt leadership techniques related to relationship and community building. Relatedly, companies could encourage supportive networks among salespeople, such as through team-building events.

Third, if legally and culturally possible, managers could personalize incentive schemes. They could assign a high variable compensation share to salespeople with high ability and social resources, but limit the variable compensation share for more stress-vulnerable salespeople.

Fourth, companies concerned with their salespeople's stress and health should sensitize their managers to the health-harming effects of their compensation decisions. Raising awareness of these effects may encourage managers to design more sustainable compensation plans. "Our study may help companies and managers set variable compensation shares that effectively balance economic interests with employees' health," says Alavi.

DURHAM, N.C. -- When you think about what separates humans from chimpanzees and other apes, you might think of our big brains, or the fact that we get around on two legs rather than four. But we have another distinguishing feature: water efficiency.

That's the take-home of a new study that, for the first time, measures precisely how much water humans lose and replace each day compared with our closest living animal relatives.

Our bodies are constantly losing water: when we sweat, go to the bathroom, even when we breathe. That water needs to be replenished to keep blood volume and other body fluids within normal ranges.

And yet, research published March 5 in the journal Current Biology shows that the human body uses 30% to 50% less water per day than our closest animal cousins. In other words, among primates, humans evolved to be the low-flow model.

An ancient shift in our body's ability to conserve water may have enabled our hunter-gatherer ancestors to venture farther from streams and watering holes in search of food, said lead author Herman Pontzer, associate professor of evolutionary anthropology at Duke University.

"Even just being able to go a little bit longer without water would have been a big advantage as early humans started making a living in dry, savannah landscapes," Pontzer said.

The study compared the water turnover of 309 people with a range of lifestyles, from farmers and hunter-gatherers to office workers, with that of 72 apes living in zoos and sanctuaries.

To maintain fluid balance within a healthy range, the body of a human or any other animal is a bit like a bathtub: "water coming in has to equal water coming out," Pontzer said.

Lose water by sweating, for example, and the body's thirst signals kick in, telling us to drink. Chug more water than your body needs, and the kidneys get rid of the extra fluid.

For each individual in the study, the researchers calculated water intake via food and drink on the one hand, and water lost via sweat, urine and the GI tract, on the other hand.

When they added up all the inputs and outputs, they found that the average person processes some three liters, or 12 cups, of water each day. A chimpanzee or gorilla living in a zoo goes through twice that much.

Pontzer says the researchers were surprised by the results because, among primates, humans have an amazing ability to sweat. Per square inch of skin, "humans have 10 times as many sweat glands as chimpanzees do," Pontzer said. That makes it possible for a person to sweat more than half a gallon during an hour-long workout -- equivalent to two Big Gulps from a 7-Eleven.

Add to that the fact that the great apes -- chimpanzees, bonobos, gorillas and orangutans -- live lazy lives. "Most apes spend 10 to 12 hours a day resting or feeding, and then they sleep for 10 hours. They really only move a couple hours a day," Pontzer said.

But the researchers controlled for differences in climate, body size, and factors like activity level and calories burned per day. So they concluded the water-savings for humans were real, and not just a function of where individuals lived or how physically active they were.

The findings suggest that something changed over the course of human evolution that reduced the amount of water our body uses each day to stay healthy.

Then as now, we could likely still only survive a few days without drinking, Pontzer said. "You probably don't break that ecological leash, but at least you get a longer one if you can go longer without water."

The next step, Pontzer says, is to pinpoint how this physiological change happened.

One hypothesis, suggested by the data, is that our body's thirst response was re-tuned so that, overall, we crave less water per calorie compared with our ape relatives. Even as babies, long before our first solid food, the water-to-calories ratio of human breast milk is 25% less than the milks of other great apes.

Another possibility lies in front of our face: Fossil evidence suggests that, about 1.6 million years ago, with the inception of Homo erectus, humans started developing a more prominent nose. Our cousins gorillas and chimpanzees have much flatter noses.

Our nasal passages help conserve water by cooling and condensing the water vapor from exhaled air, turning it back into liquid on the inside of our nose where it can be reabsorbed.

Having a nose that sticks out more may have helped early humans retain more moisture with each breath.

"There's still a mystery to solve, but clearly humans are saving water," Pontzer said. "Figuring out exactly how we do that is where we go next, and that's going to be really fun."

Using genetic engineering, researchers at UT Southwestern and Indiana University have reprogrammed scar-forming cells in mouse spinal cords to create new nerve cells, spurring recovery after spinal cord injury. The findings, published online today in Cell Stem Cell, could offer hope for the hundreds of thousands of people worldwide who suffer a spinal cord injury each year.

Cells in some body tissues proliferate after injury, replacing dead or damaged cells as part of healing. However, explains study leader Chun-Li Zhang, Ph.D., professor of molecular biology and a W.W. Caruth, Jr. Scholar in Biomedical Research at UTSW, the spinal cord typically does not generate new neurons after injury - a key roadblock to recovery. Because the spinal cord acts as a signal relay between the brain and the rest of the body, he adds, its inability to self-repair permanently halts communication between these two areas, leading to paralysis, loss of sensation, and sometimes life-threatening consequences such as an inability to control breathing or heart rate.

Zhang notes that the brain has some limited capacity to produce new nerve cells, relying on progenitor cells to turn on distinct regenerative pathways. Using this knowledge as inspiration, he and his colleagues looked for cells that might have similar potential for regeneration in the spinal cord.

\Working with a mouse model of spinal cord injury, the researchers looked in the animals' injured spinal cords for a marker normally found in immature neurons. Not only was this marker also present in the spinal cord after injury, Zhang says, but he and his team tracked down the cells that produce it: non-neuronal cells called NG2 glia.

NG2 glia serve as progenitors for cells called oligodendrocytes, which produce the insulating fat layer that surrounds neurons. They are also well-known to form glial scars following injury. Zhang's team showed that when the spinal cord was injured, these glia transiently adopted molecular and morphological markers of immature neurons.

To determine what causes NG2 glia to change, the researchers focused on SOX2, a stem cell protein induced by injury. They genetically manipulated these cells to inactivate the gene that makes this protein. When spinal cords of mice that had been manipulated were cut, the researchers saw far fewer immature neurons in the days following injury, suggesting that SOX2 plays a key role in helping NG2 glia make these cells. However, even with normal levels of SOX2, these immature neurons never matured into replacements for those affected by the injury.

Taking an opposite tack, Zhang and his colleagues used a different genetic manipulation technique to make NG2 glia overproduce SOX2. Excitingly, in the weeks after spinal cord injury, mice with this manipulation produced tens of thousands of new mature neurons. Further investigation showed that these neurons integrated into the injured area, making the new connections with existing neurons that are necessary to relay signals between the brain and body.

Even more promising, says Zhang, is that this genetic engineering led to functional improvements after spinal cord injury. Animals engineered to overproduce SOX2 in their NG2 glia performed markedly better on motor skills weeks after spinal cord injury compared with those that made normal SOX2 amounts. The reasons for this improved performance seemed to be multifold. Not only did these animals have new neurons that appeared to take over for those damaged during injury, Zhang explains, but they also had far less scar tissue at the injury site that could hinder recovery.

Zhang notes that, eventually, researchers may be able to discover safe and effective ways to overproduce SOX2 in human spinal cord injury patients, helping repair their injuries with new neurons while reducing scar tissue formation.

"The field of spinal cord injury has extensively researched trying to heal the damage with stem cells that produce new neurons, but what we're proposing here is that we may not need to transplant cells from the outside," Zhang says. "By encouraging NG2 glia to make more SOX2, the body can make its own new neurons, rebuilding from within."

In order to stay alive, the cell must provide its various organelles with all the energy elements they need, which are formed in the Golgi apparatus, its centre of maturation and redistribution of lipids and proteins. But how do the proteins that carry these cargoes - the kinesins - find their way and direction within the cell's "road network" to deliver them at the right place? Chemists and biochemists at the University of Geneva (UNIGE), Switzerland, have discovered a fluorescent chemical dye, making it possible for the first time to track the transport activity of a specific motor protein within a cell. A discovery to be read in the magazine Nature communication.

"It all started from a research that didn't go as planned," laughs Nicolas Winssinger, professor at the Department of Organic Chemistry of the Faculty of Science at UNIGE. "Initially, we wanted to develop a molecule that would make it possible to visualise the stress level of the cell, i.e. when it accumulates too much active oxygen species. During the experiment, the molecule did not work, but crystallised. Why did it crystallise? What were these crystals?"

Three hypotheses emerged as possible and the team reached out to Charlotte Aumeier, professor in the Department of Biochemistry of the Faculty of Sciences of the UNIGE to verify them. The first hypothesis suggested that crystallisation was due to the microtubules that polymerise. "Microtubules are small, rigid tubes that can grow or shrink and constitute the "road network" that allows molecules to move around the cell," explains Charlotte Aumeier. The second hypothesis made Golgi's apparatus responsible for this chemical reaction. The last possibility suggested that the crystals were the result of the small steps made by the kinesin proteins in the microtubules as they moved within the cell.

The biochemists' little thumb

To verify these different options, the UNIGE team joined forces with the National Institute of Health (NIH) in Bethesda (USA), which specialises in electron microscopy. "We first recreated microtubules that we purified, which takes 14 hours," explains Charlotte Aumeier. "For the kinesins, the motor proteins that move on microtubules and transport cargo, we isolated them from bacteria." The scientists then put together about 20 different mixtures containing the small molecule QPD, which is systematically present in the crystals, and observed which solution worked. "We wanted to know what was needed to form the crystals. The microtubules? The kinesin? Yet another protein?" asks Nicolas Winssinger.

Following various experiments, the team discovered that the formation of these crystals was caused by one of the 45 types of kinesin present in the cell. "With each small step that this kinesin protein takes on the microtubule, it uses energy that leaves a trace identified by the QPD molecule," continues the Geneva-based researcher. It is from this recognition that the crystals are formed. In this way, the crystals are chemically left behind by the passage of the kinesin, which can be tracked by scientists like a small thumb.

The opening of a new field of study

"Until now, it has not been possible to track a particular protein. With current techniques, we couldn't separate the individual kinesins, so we couldn't see which path they took precisely," continues Charlotte Aumeier. "Thanks to the development of our new chemical fluorescent dye, we can observe in detail how a protein behaves, which route it takes, its direction or even its preferred path." For the first time, scientists can visualise the walking path of motor proteins and study the fundamental question of the transport activity and distribution of cargoes in cells.

Satellite imagery shows that the area covered by kelp forests off the coast of Northern California has dropped by more than 95 percent, with just a few small, isolated patches of bull kelp remaining. Species-rich kelp forests have been replaced by "urchin barrens," where purple sea urchins cover a seafloor devoid of kelp and other algae.

A new study led by researchers at UC Santa Cruz documents this dramatic shift in the coastal ecosystem and analyzes the events that caused it. This was not a gradual decline, but an abrupt collapse of the kelp forest ecosystem in the aftermath of unusual ocean warming along the West Coast starting in 2014, part of a series of events that combined to decimate the kelp forests.

Published March 5 in Communications Biology, the study shows that the kelp forests north of San Francisco were resilient to extreme warming events in the past, surviving other strong marine heatwaves and El Niño events. But the loss of a key urchin predator, the sunflower sea star, due to sea star wasting disease left the kelp forests of Northern California without any predators of sea urchins, which are voracious grazers of kelp.

"There were a lot of disruptions at one time that led to this collapse, and the system now persists in this altered state," said first author Meredith McPherson, a graduate student in ocean science at UC Santa Cruz. "It's a naturally dynamic system that has been really resilient to extreme events in the past, but the die-off of sunflower stars caused the resilience of the ecosystem to plummet. As a result, the kelp forests were not able to withstand the effects of the marine heatwave and El Niño event combined with an insurgence of sea urchins."

The researchers used satellite imagery from the U.S. Geological Survey's Landsat missions going back to 1985 to assess historical changes in kelp forest canopy cover.

Bull kelp is the dominant canopy-forming kelp species north of San Francisco Bay, while giant kelp is dominant to the south. Both species thrive when strong upwelling of cold, deep water brings nutrients to the surface along the coast. Marine heatwaves and El Niño events suppress coastal upwelling, resulting in warm water and low nutrient conditions in which kelp grows poorly.

"There have been big changes before, when a strong El Niño has reduced the kelp canopy dramatically, but in the past it's always come back," said coauthor Raphael Kudela, professor and chair of ocean science at UC Santa Cruz. "The loss of resiliency is what made this time different--the combination of ocean warming and the loss of the sea stars allowed the urchins to take over."

Sea star wasting disease first appeared in 2013, affecting all types of sea stars along the West Coast. The sunflower sea star was among the hardest hit species and was recently was listed as critically endangered by the International Union for Conservation of Nature.

Late 2014 saw the advent of an unusual marine heatwave in the Northeast Pacific which became known as "the blob" as it spread down the West Coast in 2015. A strong El Niño event began to develop around the same time, bringing warm water up the coast from the south. The warm water coincided with an increase in sea urchin populations along the North Coast.

"The alignment of all of those events resulted in an incredibly dramatic loss of kelp," Kudela said.

Kelp forests declined all along the California coast, but not to the same extent as in Northern California. Bull kelp is an annual species that regrows each year, which may make it more sensitive to these stressors than giant kelp. But another critical difference in Northern California is the absence of other urchin predators such as sea otters, which have enabled patches of healthy kelp forest to persist in Monterey Bay, for example.

"Sea otters haven't been seen on the North Coast since the 1800s," McPherson said. "From what we observed in the satellite data from the last 35 years, the kelp had been doing well without sea otters as long as we still had sunflower stars. Once they were gone, there were no urchin predators left in the system."

What that means for the future, she said, is that the prospects for recovery of the Northern California kelp forests are poor unless sunflower sea stars or some other urchin predator returns to the system. Even if temperature and nutrient conditions are good for kelp growth, new kelp plants will have a hard time getting established in the midst of the urchin barrens.

There have been some efforts to have divers manually remove urchins from selected areas and see if that can help the kelp to recover, led by the Reef Check California Program (which contributed subtidal survey data for the study). An outbreak of sea urchin disease could also potentially lead to mass mortality of urchins and give the kelp a chance to recover. In the absence of some mechanism to reduce the urchin populations, however, it will be hard to restore and maintain the kelp forests, according to McPherson.

"There's a lot of research and discussion now about the best management strategies for the future," she said. "It's important to understand and monitor the whole system. If we're going to undertake restoration efforts, we need to make sure to do it when the temperature and nutrient conditions are right for the kelp."

Kudela said ocean temperatures are beginning to cool down along the coast, after remaining above normal since 2014. "This year we are finally seeing ocean temperatures starting to cool off, so we're hoping that it reverses naturally and the kelp is able to take off again," he said. "There's really not much we can do except to keep monitoring it. Of course, the long-term solution is to reduce our carbon emissions so we don't have these extreme events."

What The Study Did: Researchers examined the association of increased anti-immigrant rhetoric during the 2016 presidential campaign with changes in the use of health care services among undocumented patients.

Authors: Joseph Nwadiuko, M.D., M.P.H., M.S.H.P., of the University of Pennsylvania Perelman School of Medicine in Philadelphia, is the corresponding author.

To access the embargoed study: Visit our For The Media website at this link https://media.jamanetwork.com/

(doi:10.1001/jamanetworkopen.2021.0763)

Editor's Note: Editor's Note: The article includes conflicts of interest and funding/support disclosures. Please see the article for additional information, including other authors, author contributions and affiliations, conflict of interest and financial disclosures, and funding and support.

Researchers from the Pan African Programme: The Cultured Chimpanzee (PanAf) at the Max Planck Institute for Evolutionary Anthropology (MPI-EVA) and a team of international researchers, collected over 5000 fecal samples from 55 sites in 18 countries across the chimpanzee range over 8 years. This is by far the most complete sampling of the species to date, with a known location of origin for every sample, thus addressing the sampling limitations of previous studies. "Collecting these samples was often a daunting task for our amazing field teams. The chimpanzees were almost all unhabituated to human presence, so it took a lot of patience, skill and luck to find chimpanzee dung at each of the sites," explains Mimi Arandjelovic, co-director of the PanAf and senior author of the study.

Jack Lester, first author of the study, explains: "We used rapidly-evolving genetic markers that reflect the recent population history of species and, in combination with the dense sampling from across their range, we show that chimpanzee subspecies have been connected, or, more likely, reconnected, for extended periods during the most recent maximal expansion of African forests."

So although chimpanzees were separated into different subspecies in their distant past, prior to the rise of recent anthropogenic disturbances, the proposed subspecies-specific geographic barriers were permeable to chimpanzee dispersal. Paolo Gratton, co-author of the study and researcher at the Università di Roma "Tor Vergata" adds: "It is widely thought that chimpanzees persisted in forest refugia during glacial periods, which has likely been responsible for isolating groups of populations which we now recognize as subspecies. Our results from fast-evolving microsatellite DNA markers however indicate that genetic connectivity in the most recent millennia mainly mirrors geographic distance and local factors, masking the older subspecies subdivisions."

Furthermore, "these results suggest that the great behavioural diversity observed in chimpanzees are therefore not due to local genetic adaptation but that they rely on behavioural flexibility, much like humans, to respond to changes in their environment," notes Hjalmar Kuehl, co-director of the PanAf and researcher at the German Centre for Integrative Biodiversity Research (iDiv).

The team also observed signals of reductions in diversity at some sites that appeared to be associated with recent anthropogenic pressures. In fact, at some locations PanAf teams visited no, or few, chimpanzees were detected despite recordings of their presence within the last decades. "Although not unforeseen, we were disheartened to already find the influence of human impacts at some field sites where genetic diversity was markedly lower than what we expected," says Jack Lester.

These results highlight the importance of genetic connectivity for chimpanzees in their recent history. "Every effort should be made to re-establish and maintain dispersal corridors across their range, with perhaps special attention to trans-national protected areas," notes Christophe Boesch, co-director of the PanAf and director of the Wild Chimpanzee Foundation. Chimpanzees are known to be adaptable to human disturbance and can survive in human-modified landscapes, however, habitat loss, zoonotic diseases, bushmeat and pet trades are all threats to chimpanzee survival. These results warn of future critical impacts on their genetic health and viability if habitat fragmentation and isolation continue unabated.

A combined treatment of irradiation and essential oil vapors could effectively destroy insects, bacteria and mold in stored grains. A team from the Institut national de la recherche scientifique (INRS), led by Professor Monique Lacroix, has demonstrated the effect of this process on insects affecting rice. The study was published in the Radiation Physics and Chemistry journal.

Microorganisms and insects are the main enemies of stored grains. Currently, the food industry uses fumigants to destroy them. However, these compounds, which evaporate or decompose into gases into air or water, are threatening human health and the environment. "When grain is fumigated, a small amount of gas is absorbed by the grain and released into the atmosphere. For food irradiation, the treatment is physical. If "new molecules" are produced, they are no different than those produced by normal processes applied to food, such as heat," says Professor Monique Lacroix.

Food irradiation refers to the exposure of food to ionizing radiation, including gamma rays and X-rays. The research team has determined the effectiveness of these two processes, both with and without essential oils.

Increasing radiosensitivity

The study aimed at testing whether the energy level of the irradiation source with variable flow rate could affect the dose (or treatment time) needed to kill 90% of insects or molds. The research team showed that gamma rays were more effective against insects than X-rays. In addition, a higher dose rate with gamma rays proved to be more effective than a low dose rate. Moreover, by adding eucalyptus and tea tree essential oils, the effectiveness significantly improved. "With the addition of essential oils, the dose needed was four to six times smaller depending on gamma dose rates. In fact, oils increase the sensitivity of insects to radiation" says Professor Lacroix.

Similar results can be seen for bacteria and moulds, even though they are more resistant to radiation. According to a previous study, microorganisms' sensitivity to irradiation increased by about 1.5 times with the addition of thyme and oregano essential oils.

The team also conducted experiments with essential oil vapors diffused in 5 kg bags of rice. In the future, the team would like to test the process in an industrial setting, through partnership with companies.

What The Study Did: In this study, many children and adolescents hospitalized for COVID-19 or multisystem inflammatory syndrome in children had neurologic involvement, mostly transient symptoms. A range of life-threatening and fatal neurologic conditions associated with COVID-19 infrequently occurred. Effects on long-term neurodevelopmental outcomes are unknown.

Authors: Adrienne G. Randolph, M.D., of Boston Children's Hospital, is the corresponding author.

To access the embargoed study: Visit our For The Media website at this link https://media.jamanetwork.com/

(doi:10.1001/jamaneurol.2021.0504)

Editor's Note: The article includes conflict of interest and funding/support disclosures. Please see the article for additional information, including other authors, author contributions and affiliations, conflict of interest and financial disclosures, and funding and support.