Earth

A Florida State University researcher is part of a team that has found varying projections on global warming trends put forth by climate change scientists can be explained by differing models' predictions regarding ice loss and atmospheric water vapor.

The work will help climate scientists reconcile various models to improve their accuracy, said Florida State University Meteorology Professor Ming Cai, one of the authors of the study published in Nature Communications .

Climate scientists agree that the Earth's surface temperature is warming, but the details of exactly where and by how much are less clear. A worst-case climate change scenario (known as the "Representative Concentration Pathway 8.5") predicted a likely increase in average global temperatures of about 2.6 degrees Celsius to 4.8 degrees Celsius (or about 4.7 degrees Fahrenheit to 8.6 degrees Fahrenheit) by 2100.

"This uncertainty limits our ability to foresee the severity of the global warming impacts on nature and human civilization," Cai said. "The more information we have about the effects of climate change around the world, the better prepared we will be."

The difference in those conclusions would mean the difference between a sea level rise of about a half-meter to close to one meter, for example.

As scientists around the world have studied the climate, they have developed their own models. Although the major components of these climate models are based on the same general physical principles, such as conservations of energy and mass, they still differ from one another in many details, which is what leads to a range of conclusions about something like the future average global temperature.

"What are the best ways to represent those details in a climate model?" Cai said. "That's something that climate science is still working to answer. The model gets into the 'art' part of science."

The researchers investigated the variability among 25 climate models that participated in the United Nations' Intergovernmental Panel on Climate Change. They found that climate models that predicted higher average temperatures for the Earth's surface overall also yielded results that showed more polar ice loss and more water vapor in the atmosphere.

"We found that these two factors explain close to 99 percent of the difference in global-mean warming forecasts among these 25 climate models," Cai said. "Our findings suggest that variability among climate models could be significantly reduced by narrowing the uncertainty in models simulating ice-albedo and water vapor feedbacks."

The research also found that cloud cover is less important than scientists previously thought for explaining variation among models.

These models are tools for making forecasts for things like sea level rise, flood risk, the viability of crops and wildlife and other considerations.

"Knowing that polar ice and water vapor in the atmosphere are the most important drivers of variability in different climate models will help climate scientists further refine those models," Cai said.

With growing interest in its potential health benefits and new legislation favoring legalization in more states, cannabis use is becoming more common among older adults.

University of California San Diego School of Medicine researchers report that older adults use cannabis primarily for medical purposes to treat a variety of common health conditions, including pain, sleep disturbances and psychiatric conditions like anxiety and depression.

The study, published online October 7, 2020 in the Journal of the American Geriatrics Society, found that of 568 patients surveyed, 15 percent had used cannabis within the past three years, with half of users reporting using it regularly and mostly for medical purposes.

"Pain, insomnia and anxiety were the most common reasons for cannabis use and, for the most part, patients reported that cannabis was helping to address these issues, especially with insomnia and pain," said Christopher Kaufmann, PhD, co-first author of the study and assistant professor in the Division of Geriatrics and Gerontology in the Department of Medicine at UC San Diego.

Patients surveyed in the study were seen at the Medicine for Seniors Clinic at UC San Diego Health over a period of 10 weeks.

The researchers also found that 61 percent of the patients who used cannabis had initiated use after age 60.

"Surprisingly, we found that nearly three-fifths of cannabis users reported using cannabis for the first time as older adults. These individuals were a unique group compared to those who used cannabis in the past," said Kevin Yang, co-first author and third-year medical student at UC San Diego.

"New users were more likely to use cannabis for medical reasons than for recreation. The route of cannabis use also differed with new users more likely to use it topically as a lotion rather than by smoking or ingesting as edibles. Also, they were more likely to inform their doctor about their cannabis use, which reflects that cannabis use is no longer as stigmatized as it was previously."

Given the rise in availability of CBD-only products, which is a non-psychoactive cannabinoid in contrast to THC-containing products, the researchers said it is likely that future surveys will continue to document a larger proportion of older adults using cannabis or cannabis-based products for the first time.

"The findings demonstrate the need for the clinical workforce to become aware of cannabis use by seniors and to gain awareness of both the benefits and risks of cannabis use in their patient population," said Alison Moore, MD, senior author and chief of the Division of Geriatrics in the Department of Medicine at UC San Diego School of Medicine. "Given the prevalence of use, it may be important to incorporate evidence-backed information about cannabis use into medical school and use screening questions about cannabis as a regular part of clinic visits."

The researchers said future studies are imperative to better understanding the efficacy and safety of different formulations of cannabis in treating common conditions in older adults, both to maximize benefit and minimize harm.

"There seems to be potential with cannabis, but we need more evidence-based research. We want to find out how cannabis compares to current medications available. Could cannabis be a safer alternative to treatments, such as opioids and benzodiazepines? Could cannabis help reduce the simultaneous use of multiple medications in older persons? We want to find out which conditions cannabis is most effective in treating. Only then can we better counsel older adults on cannabis use," said Kaufmann.

Philadelphia, October 7, 2020 - With a steady growth in online grocery shopping, a new study in the Journal of Nutrition Education and Behavior, published by Elsevier, examines the availability of nutrition-related information on leading grocery store websites.

Researchers from the University of Minnesota assessed 12 US grocery websites and evaluated the availability of nutrition-related features for 26 different food items on leading grocery store websites. Nutrition facts panels and ingredient statement information were available for 85 percent of the packaged foods and nutrition facts panel information was accessible within one click of the product page for the majority of food items. However, nutrition facts panels and ingredient statement information were not universally available for food items for which labeling on product packaging is mandatory, and this information was not always easily accessed or legible.

Additionally, research found that most online stores offer the ability to filter food search results based on nutrition-related food attribute. For example, consumers may search for gluten-free options. However, the ability to sort search results by a nutrition attribute like sodium quantity per serving was not an option on any of the online stores.

"At the time we were designing this study there were very few published articles evaluating online grocery stores and very few articles evaluating even how consumers shop for groceries online in any capacity." stated Kelly Olzenak, MPH, RD, Graduate School of Public Health, University of Minnesota, Minneapolis, MN, USA. Consequently, this research paves the way for many future studies on the topic of online grocery shopping and its effect on the nutritional choices of consumers.

An analysis of published studies has found a relatively high prevalence of suicidal behaviors among physicians. The findings are published in Suicide and Life-Threatening Behavior.

The analysis included 35 studies with a total of 70,368 physicians. The lifetime prevalence of suicidal thoughts was 17.4%, while the 1-year prevalence was 8.6%, 6-month prevalence was 11.9%, and 1-month prevalence was 8.6%. The lifetime prevalence of suicidal attempts was 1.8%, while the 1-year prevalence was 0.3%.

Geographic region was associated with lifetime and 1-year prevalence of suicidal thoughts--for example, rates were higher in Europe than in the United States.

A new review published in the Journal of Research in Science Teaching highlights the potential of machine learning--a subset of artificial intelligence--in science education. Although the authors initiated their review before the COVID-19 outbreak, the pandemic highlights the need to examine cutting-edge digital technologies as we re-think the future of teaching and learning.

Based on a review of 47 studies, investigators developed a framework to conceptualize machine learning applications in science assessment. The article aims to examine how machine learning has revolutionized the capacity of science assessment in terms of tapping into complex constructs, improving assessment functionality, and facilitating scoring automaticity.

Based on their investigation, the researchers identified various ways in which machine learning has transformed traditional science assessment, as well as anticipated impacts that it will likely have in the future (such as providing personalized science learning and changing the process of educational decision-making).

"Machine learning is increasingly impacting every aspect of our lives, including education," said lead author Xiaoming Zhai, an assistant professor in the University of Georgia's Mary Frances Early's Department of Mathematics and Science Education. "It is anticipated that the cutting-edge technology may be able to redefine science assessment practices and significantly change education in the future."

From ants to primates, 'Napoleonic' intelligence has evolved to help animals contend with the myriad cognitive challenges arising from interactions with rival outsiders, suggest researchers at the University of Bristol in a paper published in Nature Communications today [Tuesday 6 October].

Antagonistic and co-operative social interactions within groups have long been suggested to drive the evolution of big brains. But animals from across the social spectrum must constantly juggle threats and opportunities from outsiders too.

Interactions with outsiders have been little considered in the context of cognitive evolution. Drawing on their varied backgrounds in animal cognition, intergroup conflict and social evolution, the Bristol scientists have expanded the Social Intelligence Hypothesis to include this missing social axis.

Dr Ben Ashton, honorary research associate and lead author from the School of Biological Sciences, said: "Outside threats and opportunities likely present a range of cognitive challenges. Animals have to defend their territories, find mates and compete for resources - we believe negotiating such challenges requires considerable brain power."

Andy Radford, Professor of Behavioural Ecology and senior author, continued: "A vast amount of time and effort in the animal kingdom is devoted to gathering information about outsiders, and to avoiding, exploiting and winning interactions with them. But this aspect of sociality has traditionally been ignored in explanations of animal brain evolution."

Dr Patrick Kennedy, research associate and co-author added: "Biologists have shown how interactions with groupmates can generate 'Machiavellian' intelligence, the House of Cards-style cunning needed to get ahead in social politics within groups. We argue that animals also need 'Napoleonic' intelligence, the more Game of Thrones-style sharpness necessary to triumph in a world packed with rival outsiders."

Niccolò Machiavelli is perhaps best-known for his political treatise The Prince, a commentary on how to establish and retain power; the term Machiavellian subsequently became synonymous with ruthless realpolitik. Napoleon Bonaparte is considered one of the greatest military minds in history; the strategic intelligence underlying the Napoleonic campaigns is still used as an example in textbook warfare today.

Dr Ashton, now at Macquarie University, Australia, said: "Cognitive evolution is one of the most hotly debated topics in biology, with considerable uncertainty remaining over the predominant drivers. Some of that uncertainty might be because a whole social axis - interactions with rival outsiders - has been largely ignored in both theoretical and empirical work."

Dr Kennedy added: "The possibility that outsiders have shaped intelligence has been suggested before, in particular by two of the pioneers of social evolution - Richard Alexander and William Hamilton. However, these brainy primates were thinking only of our own species; it is time to expand their insights beyond human cognition."

Professor Radford concluded: "What do big-brained animals have in common with Napoleon Bonaparte? We suspect that their ancestors possessed the intelligence to triumph in one of the highest-stakes games of all: outmanoeuvring outsiders."

Training parents of children with autism spectrum disorder virtually about early behavioral intervention is an accessible and effective approach during the coronavirus pandemic or in other instances when in-person instruction is not possible, according to a Rutgers researcher.

The study, which was published in The Journal of Applied Behavioral Analysis, broadens the treatment options for parents of children with autism who lack access to in-person training as they do now during the coronavirus pandemic.

"Since parents play an important role in the treatment of their children's autism symptoms, developing effective, efficient, socially acceptable and accessible training so they can implement these interventions is critically important," said lead author Wayne Fisher, director of the Rutgers Center for Autism Research, Education and Services at the Rutgers Brain Health Institute. "However, many parents do not have access to this complex training due to geographic, economic and time barriers -- or more recently the pandemic, which has made in-person training difficult."

Autism spectrum disorder affects approximately one in 59 children in the United States. Children who do not receive early intensive behavioral intervention - part of the applied behavior analysis-based treatment (ABA) approach - have been shown to find it difficult to secure employment, maintain friends and live independently as adults. Parents are trained on the intervention, which aims to reduce problem behavior, such as aggression, and to increase adaptive behavior, such as communication and social skills, through a combination of e-learning and play-based training approaches.

In the study, Fisher and his colleagues recruited 25 adults who had a child diagnosed with an autism spectrum disorder and had no experience in ABA intervention and assigned 13 to the treatment group and 12 to a control group that did not receive the virtual training but continued with other behavioral programs they currently used.

The study evaluated how well parents implemented the behavioral procedures they learned through virtual training and scripted role-play with a specialist. Before and after the virtual learning, trained observers watched videos of how parents in both groups responded to researchers who used a script to simulate appropriate behaviors, such as initiating conversation, and problem behaviors, such as aggression, that are commonly exhibited by children with autism. They found that parents in the treatment group showed large and statistically significant improvements over the group that did not receive the training.

The study also found that parents rated the telehealth training as a 6.6 on a 7-point scale, showing that it is easy to use, comprehensive and effective.

"The findings show that parents can be virtually trained in these complex procedures and that the methods are ones that they find easy to use," Fisher said. "You want these treatments to not only work in the clinic with the trained technicians but also in a child's daily life, helping parents to manage behavior and helping the child communicate better and to do activities like go out to dinner."

Children are more likely to introduce violent themes into their pretend play, such as imaginary fighting or killing, if they are with playmates whom peers consider bad-tempered, new research suggests.

Academics from the University of Cambridge believe that the tendency for children to introduce aggressive themes in these situations - which seems to happen whether or not they are personally easy to anger - may be because they are 'rehearsing' strategies to cope with hot-headed friends.

The finding comes from an observational study of more than 100 children at a school in China, who were asked to play with toys in pairs. Children whose play partners were considered bad-tempered by their peers were 45% more likely to introduce aggressive themes into their pretend play than those whose partners were reckoned to be better at controlling their temper.

Importantly, however, a child's own temperament did not predict the level of make-believe aggression. Instead, children often appeared to introduce these themes specifically in response to having an irritable playmate.

This may mean that in certain cases aggressive make-believe play actually helps children's social and emotional development. The paper's authors stress, however, that further research will be needed before they can provide definitive guidance for parents or practitioners.

Dr Zhen Rao, from the Centre for Research on Play in Education, Development and Learning (PEDAL), at the Faculty of Education, University of Cambridge, said: "If children have a friend who is easily angered, and particularly if they haven't coped well with that behaviour, it's possible that they will look for ways to explore it through pretend play. This gives them a safe context in which to try out different ways of handling difficult situations next time they crop up in real life."

Aggressive pretend play has been the subject of considerable wider research, much of which aims to understand whether it predicts similarly aggressive real-life behaviours. Most of these studies, however, tend to focus on whether these associations are linked to the child's own temperament, rather than that of the children they are playing with.

The Cambridge study aimed to understand how far aggressive pretend play is associated with a play partner's anger expression. It also distinguished between aggressive pretend play and its 'non-aggressive, negative' variant: for example, pretend play that involves imagining someone who is sick or unhappy.

The research was carried out with 104 children, aged seven to 10, at a school in Guangzhou in China, as part of a wider project that the team were undertaking in that region.

Participants were asked to organise themselves into pairs - many of them therefore picking friends - and were then filmed playing for 20 minutes. The toys they were given was deliberately neutral in character (for example, there were no toy weapons), and the children could play however they wanted.

The researchers then coded 10-minute samples of each pair in 120 five-second segments, earmarking instances of pretend play, aggressive themes, and non-aggressive negative themes.

Separately, they also asked peers to rate the children's tendency to become angry. Each of the 104 children in the study was rated by, on average, 10 others, who were asked to decide whether they were good at keeping their temper, easily angered, or 'somewhere in between'.

The researchers then analysed the data using a statistical model called an Actor-Partner Interdependence Model, which is a means of measuring and testing the influence that two individuals have on one another. This allowed them to work out how far children were playing a certain way of their own volition, and how far they were being influenced by their partner.

On average, the children spent only about a fifth of their recorded session participating in pretend play, of which around 10% involved aggressive themes and 8% involved non-aggressive negative themes. Pretend play was observed in all children. More than half (53.5%) showed at least one instance of aggressive pretend play, and 43% of the children showed at least one instance of negative pretend play.

The children's own ability to control their temper, as reported by their peers, did not significantly predict how much their pretend play involved aggressive themes. If they had a play partner who was considered quick to anger, however, they were 45% more likely to create pretend situations that involved some sort of aggressive element. This percentage is to some extent shaped by how the data was segmented, but nonetheless indicates a greater likelihood that children will do this if they are playing with someone peers regard as easy to anger.

There was no evidence to suggest that either child's temperament influenced the frequency of non-aggressive, negative pretend play. The researchers also found that boys were 6.11 times likelier to engage in aggressive pretend play than girls.

The theory that children may introduce these themes to rehearse ways of handling bad-tempered peers is only one possible explanation. For example, it may also represent an attempt to stop playmates becoming angry by giving them a pretend situation in which to 'let off steam', or simply to keep them playing by appealing to their nature.

"Our study highlights the importance of taking into account a social partner's emotional expression when understanding aggressive pretend play," Rao added. "Further research is clearly needed to help us better understand this in different social contexts. The possibility that children might be working out how to handle tricky situations through pretend play suggests that for some children, this could actually be a way of developing their social and emotional skills."

Proteins transduce information and signals within the human body by changes in their structures. For example, hormones binding to their target proteins cause a structural change which in turn opens new binding sites for other proteins elsewhere on the surface of the protein. Researchers refer to this coupling of different, distant binding sites as allostery. An interruption of this coupling leads to signals not being passed on.

This can be achieved by molecules specifically designed for this purpose, which thereby obtain pharmacological effects as analgesics or chemotherapeutic agents. To selectively design such molecules, scientists need to learn more about the possible mechanisms of allostery. A team led by Prof. Dr. Gerhard Stock from the Biomolecular Dynamics group at the Institute of Physics at the University of Freiburg and Prof. Dr. Peter Hamm from the Institute of Chemistry at the University of Zurich, Switzerland provides important insights into the molecular details of allostery in the journal PNAS.

The researchers tracked time-resolved allosteric changes in the test protein PDZ2, which are caused by the binding of a peptide ligand. To this end, the research group at the University of Zurich performed time-resolved vibrational spectroscopy, while the physicists at the University of Freiburg simulated the corresponding changes on an atomistic level using the bwHPC cluster BinAC at Tübingen. This combination enabled the scientists to understand how a change in the ligand binding mode induces protein structure changes passing through the protein with atomic resolution and a time scale range from picoseconds to microseconds. The real-time observation of signal transduction in proteins showed that allostery is based on changes in both the structure and dynamics of the protein, which exhibits hierarchical dynamics, where a structural change takes about ten times longer than a preceding change.

CHAMPAIGN, Ill. -- Researchers working to maximize solar panel efficiency said layering advanced materials atop traditional silicon is a promising path to eke more energy out of sunlight. A new study shows that by using a precisely controlled fabrication process, researchers can produce multilayered solar panels with the potential to be 1.5 times more efficient than traditional silicon panels.

The results of the study led by University of Illinois Urbana-Champaign engineer Minjoo Larry Lee are published in the journal Cell Reports Physical Sciences.

"Silicon solar panels are prevalent because they are affordable and can convert a little over 20% of the sun's light into usable electricity," said Lee, a professor of electrical and computer engineering and Holonyak Micro and Nanotechnology Lab affiliate. "However, just like silicon computer chips, silicon solar cells are reaching the limit of their abilities, so finding a way to increase efficiency is attractive to energy providers and consumers."

Lee's team has been working to layer the semiconductor material gallium arsenide phosphide onto silicon because the two materials complement each other. Both materials absorb visible light strongly, but gallium arsenide phosphide does so while generating less waste heat. In contrast, silicon excels at converting energy from the infrared part of the solar spectrum just beyond what our eyes can see, Lee said.

"It is like a sports team. You are going to have some fast people, some who are strong and some with great defensive skills," he said. "In a similar way, tandem solar cells work as a team and take advantage of the best properties of both materials to make a single, more efficient device."

While gallium arsenide phosphide and other semiconductor materials like it are efficient and stable, they are expensive, so making panels composed entirely from them is not reasonable for mass production at this time. Hence, Lee's team uses low-cost silicon as a starting point for its research.

During fabrication, material defects find their way into the layers, particularly at interfaces between the silicon and gallium arsenide phosphide, Lee said. Tiny imperfections form whenever materials with different atomic structure are layered onto silicon, compromising both performance and reliability.

"Anytime you switch from one material to another, there is always a risk of creating some disorder in the transition," Lee said. "Shizhao Fan, the lead author of the study, developed a process for forming pristine interfaces in the gallium arsenide phosphide cell, which led to a vast improvement over our earlier work in this area."

"Eventually, a utility company could use this technology to get 1.5 times more energy out of the same amount of land on its solar farms, or a consumer could use 1.5 times less space for rooftop panels," he said.

Lee said obstacles remain on the path to commercialization, but he is hopeful that energy providers and consumers will see the value in using stable materials to achieve a performance boost.

Census - Remote population counting

Oak Ridge National Laboratory scientists helped count the population of Nigeria - all without leaving the lab.

Medical teams with the Bill and Melinda Gates Foundation needed help finding patients while vaccinating for polio in Nigeria, a nation of roughly 190 million people. The last national census, conducted in 2006, did little good a decade later.

Researchers at ORNL and the University of Southampton estimated population counts for every village and neighborhood in Nigeria using satellite imagery and a national sample survey, called a microcensus.

"These estimates helped them figure out where to send people, how many vaccine kits to bring, how many children to expect when they went to a village," said ORNL's Eric Weber, who designed the microcensus described in the Proceedings of the National Academy of Sciences.

"We were able to do this by sampling just a tiny fraction of households." - Matt Lakin

Media contact: Amy Reed 865.241.3802reedac@ornl.gov

Image: https://www.ornl.gov/sites/default/files/2020-10/F1%20Large%20v2-03.jpg

Caption: ORNL scientists used satellite imagery and a national sample survey to design a microcensus for Nigeria that helps find patients in need of vaccination. Credit: Adam Malin/ORNL, U.S. Dept. of Energy

Nuclear - Slowing corrosion

Irradiation may slow corrosion of alloys in molten salt, a team of Oak Ridge National Laboratory scientists has found in preliminary tests.

The researchers put samples of stainless steel and a nickel-based alloy in capsules in the Ohio State University Research Reactor and exposed them to a molten chloride salt with simultaneous neutron irradiation. In their experiment, steel that was irradiated in molten salt showed less corrosion than samples that went through the same environmental treatment but without irradiation.

Though a small sample size was used in the study, further research could support their findings and inform future molten salt reactor designs.

"These types of irradiation experiments help ORNL generate data directly impacting material selections for reactor designers," said ORNL's Dianne Ezell. "This could be a significant step in overcoming one of the largest hurdles for molten salt reactors."

Media Contact:Kristi Nelson Bumpus865.235.1381bumpuskl@ornl.gov

Image:https://www.ornl.gov/sites/default/files/2020-10/salt_irr_01.jpg

Caption:An ORNL researcher holds a capsule of molten salt. Preliminary experiments seem to indicate that irradiation can slow corrosion of metal in liquid salt. Credit: ORNL, U.S. Dept. of Energy

Image:https://www.ornl.gov/sites/default/files/2020-10/salt_irr_02.jpg

Caption:An ORNL researcher holds a test specimen for a study of whether irradiation can slow corrosion of metal in liquid salt. Preliminary experiments seem to indicate that it can. Credit: ORNL, U.S. Dept. of Energy

Materials - Turning down the heat

Scientists at Oak Ridge National Laboratory and the University of Tennessee designed and demonstrated a method to make carbon-based materials that can be used as electrodes compatible with a specific semiconductor circuitry.

The work bridges nanoscale 3D printing and widely available processes for complementary metal-oxide-semiconductor, or CMOS, technologies to enable biosensors for biomedical applications.

3D printing electrodes on CMOS circuitry from a polymer precursor requires high, yet regulated, temperatures - typically around 900 degrees Celsius - to carbonize the electrode structure. The challenge is to avoid damaging the CMOS chip.

The team's novel method, performed at the Center for Nanophase Materials Sciences at ORNL, used two photon polymerization and annealing processes to achieve and verify carbonization below 550 degrees.

"We've shown that you can convert a polymer to carbon directly on a chip in a way that can be useful for electrochemical sensing," said ORNL's Nickolay Lavrik.

Media contact:Karen Dunlap865.696.5910dunlapkk@ornl.gov

Image:https://www.ornl.gov/sites/default/files/2020-10/Lavrik%20Story%20Tip.jpg

Caption:Shown here is an on-chip carbonized electrode microstructure from a scanning electron microscope. Credit: ORNL, U.S. Dept. of Energy

HOUSTON -- Rome wasn't built in a day, but some of Earth's finest gemstones were, according to new research from Rice University.

Aquamarine, emerald, garnet, zircon and topaz are but a few of the crystalline minerals found mostly in pegmatites, veinlike formations that commonly contain both large crystals and hard-to-find elements like tantalum and niobium. Another common find is lithium, a vital component of electric car batteries.

"This is one step towards understanding how Earth concentrates lithium in certain places and minerals," said Rice graduate student Patrick Phelps, co-author of a study published online in Nature Communications. "If we can understand the basics of pegmatite growth rates, it's one step in the direction of understanding the whole picture of how and where they form."

Pegmatites are formed when rising magma cools inside Earth, and they feature some of Earth's largest crystals. South Dakota's Etta mine, for example, features log-sized crystals of lithium-rich spodumene, including one 42 feet in length in weighing an estimated 37 tons. The research by Phelps, Rice's Cin-Ty Lee and Southern California geologist Douglas Morton attempts to answer a question that has long vexed mineralogists: How can such large crystals be in pegmatites?

"In magmatic minerals, crystal size is traditionally linked to cooling time," said Lee, Rice's Harry Carothers Wiess Professor of Geology and chair of the Department of Earth, Environmental and Planetary Sciences at Rice. "The idea is that large crystals take time to grow."

Magma that cools rapidly, like rock in erupted lavas, contains microscopic crystals, for example. But the same magma, if cooled over tens of thousands of years, might feature centimeter-sized crystals, Lee said.

"Pegmatites cool relatively quickly, sometimes in just a few years, and yet they feature some of the largest crystals on Earth," he said. "The big question is really, 'How can that be?'"

When Phelps began the research, his most immediate questions were about how to formulate a set of measurements that would allow him, Lee and Morton to answer the big question.

"It was more a question of, 'Can we figure out how fast they actually grow?'" Phelps said. "Can we use trace elements -- elements that don't belong in quartz crystals -- to figure out the growth rate?"

It took more than three years, a field trip to gather sample crystals from a pegmatite mine in Southern California, hundreds of lab measurements to precisely map the chemical composition of the samples and a deep dive into some 50-year-old materials science papers to create a mathematical model that could transform the chemical profiles into crystal growth rates.

"We examined crystals that were half an inch wide and over an inch long," Phelps said. "We showed those grew in a matter of hours, and there is nothing to suggest the physics would be different in larger crystals that measure a meter or more in length. Based on what we found, larger crystals like that could grow in a matter of days."

Pegmatites form where pieces of Earth's crust are drawn down and recycled in the planet's molten mantle. Any water that's trapped in the crust becomes part of the melt, and as the melt rises and cools, it gives rise to many kinds of minerals. Each forms and precipitates out of the melt at a characteristic temperature and pressure. But the water remains, making up a progressively higher percentage of the cooling melt.

"Eventually, you get so much water left over that it becomes more of a water-dominated fluid than a melt-dominated fluid," Phelps said. "The leftover elements in this watery mixture can now move around a lot faster. Chemical diffusion rates are much faster in fluids and the fluids tend to flow more quickly. So when a crystal starts forming, elements can get to it faster, which means it can grow faster."

Crystals are ordered arrangement of atoms. They form when atoms naturally fall into that arranged pattern based on their chemical properties and energy levels. For example, in the mine where Phelps collected his quartz samples, many crystals had formed in what appeared to be cracks that had opened while the pegmatite was still forming.

"You see these pop up and go through the layers of pegmatite itself, almost like veins within veins," Phelps said. "When those cracks opened, that lowered the pressure quickly. So the fluid rushed in, because everything's expanding, and the pressure dropped dramatically. All of a sudden, all the elements in the melt are now confused. They don't want to be in that physical state anymore, and they rapidly start coming together in crystals."

To decipher how quickly the sample crystals grew, Phelps used both cathodoluminescence microscopy and laser ablation with mass spectrometry to measure the precise amount of trace elements that had been incorporated into the crystal matrix at dozens of points during growth. From experimental work done by materials scientists in the mid-20th century, Phelps was able to decipher the growth rates from these profiles.

"There are three variables," he said. "There's the likelihood of things getting brought in. That's the partition coefficient. There's how fast the crystal is growing, the growth rate. And then there's the diffusivity, so how quickly elemental nutrients are brought to the crystal."

Phelps said the fast growth rates were quite a surprise.

"Pegmatites are pretty short-lived, so we knew they had to grow relatively fast," he said. "But we were showing it was a few orders of magnitude faster than anyone had predicted.

"When I finally got one of these numbers, I remember going into Cin-Ty's office, and saying, 'Is this feasible? I don't think this is right.'" Phelps recalled. "Because in my head, I was still kind of thinking about a thousand-year time scale. And these numbers were meaning days or hours.

"And Cin-Ty said, 'Well, why not? Why can't it be right?'" Phelps said. "Because we'd done the math and the physics. That part was sound. While we didn't expect it to be that fast, we couldn't come up with a reason why it wasn't plausible."

Researchers looking at the brainstems of children and young adults exposed lifelong to air pollution in Mexico City have discovered disturbing evidence of harm.

Previous studies have linked fine particulate air pollution exposure with Alzheimer's disease, and researchers have also reported evidence of air pollution-derived nanoparticles in the frontal cortex of the brain.

But after examining the brainstems of 186 young Mexico City residents aged between 11 months and 27 years of age, researchers, including Professor Barbara Maher from Lancaster University, found markers not only of Alzheimer's disease, but also of Parkinson's and of motor neurone disease (MND) too.
These markers of disease were coupled with the presence of tiny, distinctive nanoparticles within the brainstem - their appearance and composition indicating they were likely to come from vehicle pollution.

This has led researchers to conclude that air pollution of this nature - whether inhaled or swallowed - puts people at risk of potential neurological harm.
The brainstem is the posterior part of the brain which regulates the central nervous system, controls heart and breathing rates, and how we perceive the position and movement of our body, including, for example, our sense of balance.

Professor Maher said: "Not only did the brainstems of the young people in the study show the 'neuropathological hallmarks' of Alzheimer's, Parkinson's and MND, they also had high concentrations of iron-, aluminium- and titanium-rich nanoparticles in the brainstem - specifically in the substantia nigra, and cerebellum.

"The iron-and aluminium-rich nanoparticles found in the brainstem are strikingly similar to those which occur as combustion- and friction-derived particles in air pollution (from engines and braking systems).

"The titanium-rich particles in the brain were different - distinctively needle-like in shape; similar particles were observed in the nerve cells of the gut wall, suggesting these particles reach the brain after being swallowed and moving from the gut into the nerve cells which connect the brainstem with the digestive system."

The 'neuropathological hallmarks' found even in the youngest infant (11 months old) included nerve cell growths, and plaques and tangles formed by misfolded proteins in the brain. Damage to the substantia nigra is directly linked with the development of Parkinson's disease in later life. Protein misfolding linked previously with MND was also evident, suggesting common causal mechanisms and pathways of formation, aggregation and propagation of these abnormal proteins.

The one thing common to all of the young people examined in the study was their exposure to high levels of particulate air pollution.
Professor Maher says that the associations between the presence of damage to cells and their individual components - especially the mitochondria (key for generation of energy, and signalling between cells) - and these metal-rich nanoparticles are a 'smoking gun'.

Such metal-rich particles can cause inflammation and also act as catalysts for excess formation of reactive oxygen species, which are known to cause oxidative stress and eventual death of neurons. Critically, the brainstems of age- and gender- matched controls who lived in lower-pollution areas have not shown the neurodegenerative pathology seen in the young Mexico City residents.

These new findings show that pollution-derived, metal-rich nanoparticles can reach the brainstem whether by inhalation or swallowing, and that they are associated with damage to key components of nerve cells in the brainstem, including the substantia nigra.

Even in these young Mexico City residents, the type of neurological damage associated with Alzheimer's, Parkinson's and motor neurone diseases is already evident. These data indicate the potential for a pandemic of neurological disease in high-pollution cities around the world as people experience longer lifespans, and full symptoms of earlier, chronic neurological damage develop.

Professor Barbara Maher said: "It's critical to understand the links between the nanoparticles you're breathing in or swallowing and the impacts those metal-rich particles are then having on the different areas of your brain.

"Different people will have different levels of vulnerability to such particulate exposure but our new findings indicate that what air pollutants you are exposed to, what you are inhaling and swallowing, are really significant in development of neurological damage.

"With this in mind, control of nanoparticulate sources of air pollution becomes critical and urgent."

New research from the FAMU-FSU College of Engineering combines climate and land use projections to predict water availability, information that is crucial for the preparations of resource managers and land-use planners.

"This research presented a new method that can be used to generate future climate data for the existing hydrological models," said Gang Chen, a professor of civil and environmental engineering at the college. "With the integration of more reliable future climate data, the existing hydrological models can more accurately project future water scenarios in the face of climate change."

Chen is leading a team of experts to produce new data techniques to improve hydrological modeling that is essential for water resource management planning. Their work was published in WATER.

The researchers used their method to examine the hydrological processes in Alabama's Upper Choctawhatchee River Watershed, which eventually flows into Florida and empties into the Choctawhatchee Bay. They integrated land use projections with future climate data to study the combined effects on the hydrological response of the watershed.

"Using water balance simulations, we discovered that surface runoff and evapotranspiration are dominant pathways for water loss in the Southeast," Chen said.

Yashar Makhtoumi, a doctoral candidate in the Department of Civil and Environmental Engineering, is working with Chen on new data downscaling techniques. The innovative process provides more data and improves modeling outcomes.

"Few research projects have been done to investigate the combined effects of land use change and climate change using projections," Makhtoumi said.

The results of the study showed the effects on water resource variables were seasonal. Surface runoff caused the most significant changes in various simulations, and evapotranspiration was also an issue, though to a lesser degree. The models indicate that by midcentury, more frequent extremes in water balance are projected to be an issue.

Although the research focuses on a single watershed, the researchers believe their work could be applicable on a wider scale. That's important for a state like Florida, where population growth, development and climate change are forcing residents and planners to realize the limitations of the state's water supply.

"Our model demonstrated that it could capture hydrologic parameters accurately and could be used for future studies of water quality," Chen said. "It can provide the necessary data to determine sustainable conservation practices needed now and in the future, and help manage and protect our water resources."

New analysis of the DNA sequence of the male-specific Y chromosomes from all living species of the great ape family helps to clarify our understanding of how this enigmatic chromosome evolved. A clearer picture of the evolution of the Y chromosome is important for studying male fertility in humans as well as our understanding of reproduction patterns and the ability to track male lineages in the great apes, which can help with conservation efforts for these endangered species.

A team of biologists and computer scientists at Penn State sequenced and assembled the Y chromosome from orangutan and bonobo and compared those sequences to the existing human, chimpanzee, and gorilla Y sequences. From the comparison, the team were able to clarify patterns of evolution that seem to fit with behavioral differences between the species and reconstruct a model of what the Y chromosome might have looked like in the ancestor of all great apes.

A paper describing the research appears October 5, 2020 in the journal Proceedings of the National Academy of Sciences.

"The Y chromosome is important for male fertility and contains the genes critical for sperm production, but it is often neglected in genomic studies because it is so difficult to sequence and assemble," said Monika Cechova, a graduate student at Penn State at the time of the research and co-first author of the paper. "The Y chromosome contains a lot of repetitive sequences, which are challenging for DNA sequencing, assembling sequences, and aligning sequences for comparison. There aren't out-of-the-box software packages to deal with the Y chromosome, so we had to overcome these hurdles and optimize our experimental and computational protocols, which allowed us to address interesting biological questions."

The Y chromosome is unusual. It contains relatively few genes, many of which are involved in male sex determination and sperm production; large sections of repetitive DNA, short sequences repeated over and over again; and large DNA palindromes, inverted repeats that can be many thousands of letters long and read the same forwards and backwards.

Previous work by the team comparing human, chimpanzee, and gorilla sequences had revealed some unexpected patterns. Humans are more closely related to chimpanzees, but for some characteristics, the human Y was more similar to the gorilla Y.

"If you just compare the sequence identity--comparing the As,Ts, Cs, and Gs of the chromosomes--humans are more similar to chimpanzees, as you would expect," said Kateryna Makova, Pentz Professor of Biology at Penn State and one of the leaders of the research team. "But if you look at which genes are present, the types of repetitive sequences, and the shared palindromes, humans look more similar to gorillas. We needed the Y chromosome of more great ape species to tease out the details of what was going on."

The team, therefore, sequenced the Y chromosome of a bonobo, a close relative of the chimpanzee, and an orangutan, a more distantly related great ape. With these new sequences, the researchers could see that the bonobo and chimpanzee shared the unusual pattern of accelerated rates of DNA sequence change and gene loss, suggesting that this pattern emerged prior to the evolutionary split between the two species. The orangutan Y chromosome, on the other hand, which serves as an outgroup to ground the comparisons, looked about like what you expect based on its known relationship to the other great apes.

"Our hypothesis is that the accelerated change that we see in chimpanzees and bonobos could be related to their mating habits," said Rahulsimham Vegesna, a graduate student at Penn State and co-first author of the paper. "In chimpanzees and bonobos, one female mates with multiple males during a single cycle. This leads to what we call 'sperm competition,' the sperm from several males trying to fertilize a single egg. We think that this situation could provide the evolutionary pressure to accelerate change on the chimpanzee and bonobo Y chromosome, compared to other apes with different mating patterns, but this hypothesis, while consistent with our findings, needs to be evaluated in subsequent studies."

In addition to teasing out some of the details of how the Y chromosome evolved in individual species, the team used the set of great ape sequences to reconstruct what the Y chromosome might have looked like in the ancestor of modern great apes.

"Having the ancestral great ape Y chromosome helps us to understand how the chromosome evolved," said Vegesna. "For example, we can see that many of the repetitive regions and palindromes on the Y were already present on the ancestral chromosome. This, in turn, argues for the importance of these features for the Y chromosome in all great apes and allows us to explore how they evolved in each of the separate species."

The Y chromosome is also unusual because, unlike most chromosomes it doesn't have a matching partner. We each get two copies of chromosomes 1 through 22, and then some of us (females) get two X chromosomes and some of us (males) get one X and one Y. Partner chromosomes can exchange sections in a process called 'recombination,' which is important to preserve the chromosomes evolutionarily. Because the Y doesn't have a partner, it had been hypothesized that the long palindromic sequences on the Y might be able to recombine with themselves and thus still be able to preserve their genes, but the mechanism was not known.

"We used the data from a technique called Hi-C, which captures the three-dimensional organization of the chromosome, to try to see how this 'self-recombination' is facilitated," said Cechova. "What we found was that regions of the chromosome that recombine with each other are kept in close proximity to one another spatially by the structure of the chromosome."

"Working on the Y chromosome presents a lot of challenges," said Paul Medvedev, associate professor of computer science and engineering and of biochemistry and molecular biology at Penn State and the other leader of the research team. "We had to develop specialized methods and computational analyses to account for the highly repetitive nature of the sequence of the Y. This project is truly cross-disciplinary and could not have happened without the combination of computational and biological scientists that we have on our team."