Earth

WEST LAFAYETTE, Ind. -- What do bones and 3D-printed buildings have in common? They both have columns and beams on the inside that determine how long they last.

Now, the discovery of how a "beam" in human bone material handles a lifetime's worth of wear and tear could translate to the development of 3D-printed lightweight materials that last long enough for more practical use in buildings, aircraft and other structures.

A team of researchers at Cornell University, Purdue University and Case Western Reserve University found that when they mimicked this beam and made it about 30% thicker, an artificial material could last up to 100 times longer.

"Bone is a building. It has these columns that carry most of the load and beams connecting the columns. We can learn from these materials to create more robust 3D-printed materials for buildings and other structures," said Pablo Zavattieri, a professor in Purdue's Lyles School of Civil Engineering.

Bones get their durability from a spongy structure called trabeculae, which is a network of interconnected vertical plate-like struts and horizontal rod-like struts acting as columns and beams. The denser the trabeculae, the more resilient the bone for everyday activities. But disease and age affect this density.

In a study published in the Proceedings of the National Academy of Sciences, the researchers found that even though the vertical struts contribute to a bone's stiffness and strength, it is actually the seemingly insignificant horizontal struts that increase the fatigue life of bone.

Christopher Hernandez's group at Cornell had suspected that horizontal strut structures were important for bone durability, contrary to commonly held beliefs in the field about trabeculae.

"When people age, they lose these horizontal struts first, increasing the likelihood that the bone will break from multiple cyclic loads," said Hernandez, a professor of mechanical, aerospace and biomedical engineering.

Studying these structures further could inform better ways to treat patients suffering from osteoporosis.

Meanwhile, 3D-printed houses and office spaces are making their way into the construction industry. While much faster and cheaper to produce than their traditional counterparts, even printed layers of cement would need to be strong enough to handle natural disasters - at least as well as today's homes.

That problem could be solved by carefully redesigning the internal structure, or "architecture," of the cement itself. Zavattieri's lab has been developing architected materials inspired by nature, enhancing their properties and making them more functional.

As part of an ongoing effort to incorporate nature's best strength tactics into these materials, Zavattieri's lab contributed to mechanical analysis simulations determining if horizontal struts might play a larger role in human bone than previously thought. They then designed 3D-printed polymers with architectures similar to trabeculae.

The simulations revealed that the horizontal struts were critical for extending the fatigue life of bone. A YouTube video is available at https://youtu.be/XK7NZMZ4YDs.

"When we ran simulations of the bone microstructure under cyclic loading, we were able to see that the strains would get concentrated in these horizontal struts, and by increasing the thickness of these horizontal struts, we were able to mitigate some of the observed strains," said Adwait Trikanad, a co-author on this work and civil engineering Ph.D. student at Purdue.

Applying loads to the bone-inspired 3D-printed polymers confirmed this finding. The thicker the horizontal struts, the longer the polymer would last as it took on load.

Because thickening the struts did not significantly increase the mass of the polymer, the researchers believe this design would be useful for creating more resilient lightweight materials.

"When something is lightweight, we can use less of it," Zavattieri said. "To create a stronger material without making it heavier would mean 3D-printed structures could be built in place and then transported. These insights on human bone could be an enabler for bringing more architected materials into the construction industry."

HOUSTON - (Dec. 5, 2019) - If coral reefs are the canary to the ocean's coal mine, it's getting awfully bleak in the Gulf of Mexico.

A new study by Rice University Earth scientists asserts: Without a rapid and dramatic reduction of greenhouse gas emissions, fragile coral reefs in the Gulf of Mexico, like those around the world, face catastrophe.

That could be bad for us all, said Sylvia Dee, a Rice assistant professor of Earth, environmental and planetary sciences. She and colleagues from Rice, the University of Texas at Austin and Louisiana State University drew their evidence from an extensive analysis of stressors on corals that line the Gulf coast.

They found the majority of shallow reefs along the coast from Texas to Florida are in poor-to-fair condition, and the predicted rise in surface temperatures and ocean acidity will severely degrade what's left by the end of the century.

The sheer speed of those changes will hamper, if not prevent, the recovery of reefs, some of which began to evolve in the gulf 420,000 years ago, Dee said.

"Part of this paper addresses whether or not reefs are adaptable to the warming temperatures and increasingly acidic oceans," said Dee, whose climate model projections were compared to years of data collected by the government and environmental scientists. "We looked for clues from periods in the past that might suggest present-day reefs have the ability to cope with heating and adapt or regenerate.

"But there's limited evidence to suggest that the adaptation could occur fast enough compared to how quickly we're warming the oceans," she said. "Millions of years ago, rates of sea surface temperature change and ocean acidification, such as those we're experiencing now, would have happened over much longer time scales."

The team's open-access study appears in an edition of Frontiers in Marine Science dedicated to the past, present and future of Gulf of Mexico reefs. The edition was inspired by an October 2018 Rice symposium on the topic organized by Adrienne Correa, an assistant professor of biosciences whose paper on gene expression of endangered coral also appears in the edition.

Most research on climate change and coral reefs to date has focused on the Great Barrier Reef and the tropical Pacific, she said. "Things are going south at a rapid rate there," Dee said. "But Gulf of Mexico reefs are also being swiftly degraded, and there hadn't been a comprehensive paper looking at the gulf alone."

The researchers noted that coral reefs support the world's fisheries, protect coastlines and promote tourism, generating billions of dollars for the global economy each year. According to one study, they support more than 70,000 jobs in southeast Florida alone.

In line with recent, dramatic reports by the Intergovernmental Panel on Climate Change and the United Nations, the researchers found that even hitting the emission targets called for by the Paris Agreement, which aim to keep global temperatures from rising more than 1.5 degrees Celsius, may not be sufficient to preserve the reefs.

Their climate model uses a benchmark known as Representative Concentration Pathways, which describes the future amount of radiative forcing, the balance between energy absorbed by the Earth from sunlight and that radiated back to space. The study assumed a forcing imbalance of +8.5 watts per square meter as the baseline for future warming. However, future greenhouse gas emissions have a direct impact on this number, which the researchers considered conservative, as it takes into account emissions measured over the past few decades.

"We used, essentially, a worst-case scenario for how humans will behave," Dee said. "But we explored both medium-range -- or medium climate change abatement -- and worst-case scenarios. Unfortunately, no matter the scenario, heating rates are high enough that we would expect almost complete coral bleaching throughout the Gulf of Mexico."

Coral bleaching refers to the expulsion of symbiotic algae that live inside coral tissues. Corals draw most of their energy from algae and begin to starve when it disappears due to rising temperatures. Sea life depends on the reef for shelter and sustenance and coral banks are a natural physical barrier that help protect coastlines by reducing erosion from wave action and storm surge.

"The best-case scenario is that we have rapid and widespread reduction of greenhouse gas emissions in the near term, the next 20 years," she said. "The corals in the Gulf of Mexico are hardy. Some survived Hurricane Mitch, and other gulf reefs have survived catastrophic, short-lived events. The concern is that if the heating gets worse every single year, it's going to be close to impossible for the corals to bounce back."

Co-author Mark Torres, an assistant professor of Earth, environmental and planetary sciences at Rice, noted models showed the secondary effects of ocean acidification may not be as dire as rapid temperature rise, but would still challenge the reefs' ability to recover.

"Corals make their skeletons around calcium carbonate," he said. "If seawater becomes so corrosive that skeletons dissolve in it, there's no adapting around that."

"Think of it like putting a tooth in a Coke can," Dee added.

Corals thrive along a narrow range of coastal shelf, so their ability to migrate to more hospitable waters is limited, Torres said. "If they grow deeper, the water is colder, but then they're further away from the light," he said. "There are physical limits to how deep they can live."

The researchers noted corals could give way to other species, like sponges, over the long term, but can't predict how that would impact the overall coral reef environment.

"Corals are the foundation of ecosystem health for most marine species," Dee said. "If the corals go away, you lose the fish, you lose everything. When we started evaluating climate model simulations for the future, we didn't know that the conditions in the Gulf of Mexico were going to be so dire."

Tokyo, Japan - Biliary tract cancer is a type of cancer that occurs in the bile ducts, which transport bile from the liver to the duodenum. While generally rare, these cancers are relatively common in Asian populations. Patients with one form of this cancer, called intrahepatic cholangiocarcinoma (ICC), have very poor outcomes and rarely survive beyond five years after their diagnosis. In a new study, researchers at Tokyo Medical and Dental University (TMDU) have uncovered a protein that may eventually help doctors predict which patients with ICC will have the worst outcomes - and that may someday lead to more effective treatments for ICC.

Recent studies have found that ICC tumors tend to have genetic mutations leading to the loss of a protein called ARID1A (AT-rich interactive domain-containing protein 1A). However, the exact role of the protein in ICC was unknown.

"ARID1A is known to take part in complexes that control gene expression," says Jun Yoshino, lead author of the study. "This hinted that loss of ARID1A could play a role in ICC by causing certain genes to turn on or off. However, it wasn't clear which genes might be affected or how their expression might impact the ICC disease course."

To answer this question, the researchers looked at ICC cell lines - cells that are grown in dishes and commonly used as a model for ICC tumors. Using the genome editing technique CRISPR/Cas9, the researchers deleted the gene coding for ARID1A, resulting in "knock-out" cells that mimic patients who have ARID1A-negative ICC tumors. The team discovered that when they removed ARID1A, the cells became especially malignant.

"We found that ARID1A suppresses a stemness gene ALDH1A1 implicated in other cancers. Removing ARID1A causes the gene to become highly overactive in ICC cells," explains Dr Yoshino. "We found that when this cancer stemness gene is overactive, it causes the cells to act much more aggressively. For example, the cells can migrate and invade neighboring groups of cells, a behavior that is very common in highly-active cancers."

The aggressive behavior of the cells suggested that ARID1A-negative ICC might represent a distinct form of the cancer, perhaps with a distinct prognosis. To confirm this suspicion, the team measured levels of ARID1A in tissue samples from patients with ICC, and then followed their medical history to see how well the patients eventually fared. They found that patients who were ARID1A-negative indeed had much poorer outcomes: five years after their diagnosis, less than 20% of ARID1A-negative patients had survived, compared with over 50% of ARID1A-positive patients.

"ARID1A-negative patients are more likely to have high levels of a tumorigenic gene, which in turn enhances the malignancy of their cancer," says Shinji Tanaka, corresponding author of the study. "This has important medical implications for patients with ICC. For one, it may be possible to use ARID1A as a biomarker to help physicians predict the prognosis of their patients. What's more, further research into how ARID1A functions could someday lead to more sophisticated treatment methods for this form of the disease."

Every day in the spring and fall since 1978, scientists and volunteers at Chicago's Field Museum have gotten up as early as 3:30 in the morning to collect fallen birds that have crashed into nearby buildings' windows. One scientist, Dave Willard, has measured every single one of the dead birds and recorded the data by hand into a ledger. That meticulous note-keeping paid off: scientists analyzed the data and learned that over the last forty years, migratory birds have been getting smaller--a change likely linked with climate change.

"When we began collecting the data analyzed in this study, we were addressing a few simple questions about year-to-year and season-to-season variation in birds. The phrase 'climate change' as a modern phenomenon was barely on the horizon. The results of this study highlight how essential long-term data sets are for identifying and analyzing trends caused by changes in our environment," says Willard, a collections manager emeritus at the Field Museum and one of the authors of a new study in Ecology Letters presenting these findings, along with lead author Brian Weeks and senior author Ben Winger from the University of Michigan.

Every night during the spring and fall migration seasons, nocturnal birds making their way through Chicago run into the windows of big buildings. Many of the birds hit the hulking glass McCormick Place, North America's largest convention center. And since McCormick Place is just over a mile away from the Field, Willard headed down there one morning in 1978 to see what he could find.

"It started as a very casual study--someone mentioned that birds sometimes run into McCormick Place, and I was curious, so I went for a walk around the building one morning," recalls Willard. "I found a couple dead birds and I brought them back to the museum--I've always wondered if there had been no birds that morning whether I would have ever bothered to go back."

Over the years, Willard and volunteers with the Chicago Bird Collision Monitors collected over 100,000 birds that had hit McCormick Place and other buildings in downtown Chicago--they now make up 20% of the Field's bird collections. Willard began to notice subtle changes in the birds' measurements over time, but it wasn't clear that statistically significant change was happening. "It's a matter of millimeters, tenths of millimeters--it's not something you know is happening until the analysis," says Willard. The Ecology Letters study's senior author, Ben Winger, began working on statistical analyses of the birds' sizes when he was still a University of Chicago graduate student working at the Field Museum; now, he's an assistant professor of ecology and evolutionary biology at the University of Michigan and an assistant curator at the U-M Museum of Zoology.

The team analyzed the measurements of 70,716 bird specimens representing 52 species; they found that the sizes of all of these species declined between 1978 and 2016. The birds' body masses, lower leg bone lengths, and overall body sizes all went down--the leg bone length decreased by 2.4% across species. Meanwhile, the birds' wingspans increased by 1.3%. The researchers suspect that these changes in body size are related to climate change.

Animals' body sizes are often tied to the climate they live in--within a species, individuals that live in cold climates tend to be bigger than their counterparts in warmer areas. This trend, called Bergmann's rule, helps animals in cold places stay warm. Since temperatures have crept up in the last forty years in the birds' summer breeding grounds north of Chicago, the researchers believe that the incredible shrinking birds might be due to climate change. Smaller bodies hold on to less heat; meanwhile, the birds' wingspans may have increased so that the birds are still able to make their long migrations, even with smaller bodies to produce the energy needed for flight.

"We had good reason to expect that increasing temperatures would lead to reductions in body size, based on previous studies. The thing that was shocking was how consistent it was. I was incredibly surprised that all of these species are responding in such similar ways," says the study's lead author, Brian Weeks, an assistant professor at the University of Michigan School for Environment and Sustainability.

"Periods of rapid warming are followed really closely by periods of decline in body size, and vice versa," Weeks says. "Being able to show that kind of detail in a morphological study is unique to our paper, as far as I know, and it's entirely due to the quality of the dataset that David Willard generated."

"It's really been a herculean effort on the part of Dave and others at the Field Museum, including co-author Mary Hennen, to get such valuable data from birds that might otherwise have been discarded after they died from building collisions," Winger adds.

Willard, however, turns praise back on Winger and Weeks: "I want to celebrate that there was someone out there who saw the dataset's value and was willing to do the work to see if it had anything to say or not."

Scientists at the National Institutes of Health found that women who use permanent hair dye and chemical hair straighteners have a higher risk of developing breast cancer than women who don't use these products. The study published online Dec. 4 in the International Journal of Cancer and suggests that breast cancer risk increased with more frequent use of these chemical hair products.

Using data from 46,709 women in the Sister Study, researchers at the National Institute of Environmental Health Sciences (NIEHS), part of NIH, found that women who regularly used permanent hair dye in the year prior to enrolling in the study were 9% more likely than women who didn't use hair dye to develop breast cancer. Among African American women, using permanent dyes every five to eight weeks or more was associated with a 60% increased risk of breast cancer as compared with an 8% increased risk for white women. The research team found little to no increase in breast cancer risk for semi-permanent or temporary dye use.

"Researchers have been studying the possible link between hair dye and cancer for a long time, but results have been inconsistent," said corresponding author Alexandra White, Ph.D., head of the NIEHS Environment and Cancer Epidemiology Group. "In our study, we see a higher breast cancer risk associated with hair dye use, and the effect is stronger in African American women, particularly those who are frequent users."

An intriguing finding was the association between the use of chemical hair straighteners and breast cancer. Dr. White and colleagues found that women who used hair straighteners at least every five to eight weeks were about 30% more likely to develop breast cancer. While the association between straightener use and breast cancer was similar in African American and white women, straightener use was much more common among African American women.

Co-author Dale Sandler, Ph.D., chief of the NIEHS Epidemiology Branch, cautioned that although there is some prior evidence to support the association with chemical straighteners, these results need to be replicated in other studies.

When asked if women should stop dyeing or straightening their hair, Sandler said, "We are exposed to many things that could potentially contribute to breast cancer, and it is unlikely that any single factor explains a woman's risk. While it is too early to make a firm recommendation, avoiding these chemicals might be one more thing women can do to reduce their risk of breast cancer."

ANN ARBOR--North American migratory birds have been getting smaller over the past four decades, and their wings have gotten a bit longer. Both changes appear to be responses to a warming climate.

Those are the main findings from a new University of Michigan-led analysis of a dataset of some 70,000 North American migratory birds from 52 species that died when they collided with buildings in Chicago.

Since 1978, Field Museum personnel and volunteers have retrieved dead birds that collided with Chicago buildings during spring and fall migrations. For each specimen, multiple body measurements are made.

The research team analyzed this remarkably detailed dataset to look for trends in body size and shape. The biologists found that, from 1978 through 2016, body size decreased in all 52 species, with statistically significant declines in 49 species.

Over the same period, wing length increased significantly in 40 species. The findings are scheduled for publication Dec. 4 in the journal Ecology Letters.

"We had good reason to expect that increasing temperatures would lead to reductions in body size, based on previous studies. The thing that was shocking was how consistent it was. I was incredibly surprised that all of these species are responding in such similar ways," said study lead author Brian Weeks, an assistant professor at the U-M School for Environment and Sustainability.

The senior author is Benjamin Winger of the U-M Department of Ecology and Evolutionary Biology and the Museum of Zoology. Weeks worked on the project as a postdoctoral researcher in Winger's lab. Co-authors include David E. Willard, the Field Museum ornithologist and collections manager emeritus who measured all 70,716 birds analyzed in the study.

The new study is the largest specimen-based analysis of body-size responses to recent warming, and it shows the most consistent large-scale responses for a diverse group of birds, Weeks said.

Several lines of evidence suggest a causal relationship between warming temperatures and the observed declines in avian body size, according to the researchers. The strongest evidence is that--embedded within the long-term trends of declining body size and increasing temperature--there are numerous short-term fluctuations in body size and temperature that appear to be synchronized.

"Periods of rapid warming are followed really closely by periods of decline in body size, and vice versa," Weeks said. "Being able to show that kind of detail in a morphological study is unique to our paper, as far as I know, and it's entirely due to the quality of the dataset that David Willard generated."

"It's really been a herculean effort on the part of Dave and others at the Field Museum, including co-author Mary Hennen, to get such valuable data from birds that might otherwise have been discarded after they died from building collisions," Winger said.

Within animal species, individuals tend to be smaller in warmer parts of their range, a pattern known as Bergmann's rule. And while the possibility of body size reduction in response to present-day global warming has been suggested for decades, evidence supporting the idea remains mixed.

The uncertainty is likely due, in part, to the scarcity of datasets like the Field Museum trove.

For each bird, Willard measured the length of a lower leg bone called the tarsus, bill length, wing length, and body mass. In birds, tarsus length is considered the most precise single measure of within-species variation in body size.

The data analysis revealed that:

Three measures of body size--tarsus length, body mass and PC1, a common measure of overall body size that combines several key body-part measurements--showed statistically significant declines. Tarsus length declined 2.4% across species.

Wing length showed a mean increase of 1.3%. Species with the fastest declines in tarsus length also showed the most rapid gains in wing length.

Mean summer temperature was significantly negatively associated with bird body size--meaning that body size decreased significantly as temperatures warmed. Temperatures at the birds' summer breeding grounds north of Chicago increased roughly 1 degree Celsius (1.8 degrees Fahrenheit) over the course of the study.

Studies of plant and animal response to climate change often focus on shifts in the geographical range of a species or the timing of events such as springtime flowering and migration. The consistency of the body-size declines reported in the new study suggests that such changes should be added to the list of challenges facing wildlife in a rapidly warming world, Weeks said.

"It's clear that there's a third component--changes in body size and shape--that's probably going to interact with changes in range and changes in timing to determine how effectively a species can respond to climate change," he said.

Long-distance bird migration is one of the most impressive feats in the animal kingdom. The extreme energetic demands of flying thousands of miles have shaped the morphology of migrating birds--their form and structure--for efficient flight.

The authors of the Ecology Letters paper suggest that the body-size reductions are a response to climate warming and that increased wing length may help offset the body-mass losses.

The researchers plan to test that idea in a follow-up project, which will again make use of the Field Museum dataset. They'll also look further into the mechanism behind the body size and shape changes and whether they are the result of a process called developmental plasticity, the ability of an individual to modify its development in response to changing environmental conditions.

The birds analyzed in the study are small-bodied songbirds that breed north of Chicago in the summer and migrate through the region in high numbers. Several species of sparrow, warbler and thrush make up the majority of the dataset, with thousands of individuals of each species documented as lethal collisions.

The observed changes in avian body size and shape are subtle--at most a couple grams' difference in body mass and a few millimeters in wing length--and are not detectable with the naked eye. The Field Museum bird collision dataset highlights the value of natural history museum specimen collections, which help scientists understand how nature changes through time, the authors note.

"When we began collecting the data analyzed in this study, we were addressing a few simple questions about year-to-year and season-to-season variations in birds," said the Field Museum's Willard. "The phrase 'climate change' as a modern phenomenon was barely on the horizon. The results from this study highlight how essential long-term data sets are for identifying and analyzing trends caused by changes in our environment."

New research suggests that social media, particularly platforms with a strong focus on image posting and viewing, is associated with disordered eating in young adolescents.

In the study, which is published in the International Journal of Eating Disorders, researchers examined data on 996 grade 7 and 8 adolescents. Behaviors related to disordered eating were reported by 51.7% of girls and 45.0% of boys, with strict exercise and meal skipping being the most common. A total of 75.4% of girls and 69.9% of boys had at least one social media account, and Instagram was the most common. A greater number of social media accounts, and greater daily time spent using them, were associated with a higher likelihood of disordered eating thoughts and behaviors.

"While a range of studies have focused on the impact of social media on body image, this is the first to examine the relationship between specific social media platforms and disordered eating behaviors and thoughts. Further, most other studies have also focused on older adolescents or young-adult women," said lead author Simon Wilksch, PhD, of Flinders University, in Australia. "Thus, to find these clear associations between disordered eating and social media use in young adolescent girls and boys suggests that much more needs to be done to increase resilience in young people to become less adversely impacted by social media pressures." Dr Wilksch and colleagues are launching an Australia-wide trial of the Media Smart Online program designed to combat such pressures, and people of any gender aged 13-25 years can email mediasmart@flinders.edu.au to register.

In a recent study, children exposed to smoking in the first 4 years of life were more likely to exhibit symptoms of hyperactivity and conduct problems. The study, which is published in the Journal of Child Psychology and Psychiatry, found that the association remained even after controlling for family poverty level, parental education, parental history of attention deficit hyperactivity disorder, hostility, depression, caregiver IQ, and obstetric complications.

The effects examined in this study, which included 1,096 children, were a function of the dosage of nicotine that children were exposed to, as quantified by the metabolic byproduct cotinine in their saliva. The findings are consistent with animal models demonstrating an effect of exposure to nicotine on ongoing brain development in regions related to hyperactivity and impulsivity.

"There is a lot of emphasis on the dangers of smoking during pregnancy, but our findings indicate that children continue to be vulnerable to the adverse effects of nicotine exposure during the first several years of life," said lead author Lisa Gatzke-Kopp, PhD.

CORVALLIS, Ore. - Long considered pests by forest managers, deer and elk can help Douglas-fir seedlings thrive under certain vegetation management conditions, a five-year study by Oregon State University shows.

The research, published today in the Journal of Applied Ecology, is important because global demand for forest products continues to rise and because wildlife conservation is often viewed as a hurdle to meeting that demand. The findings quantified the effects of intensive forest management on wildlife and wildlife habitat.

OSU College of Forestry scientists found that deer and elk can play a key role in controlling the broadleaf vegetation, such as alder and maple, that compete with the "crop trees" - the Douglas-fir seedlings - in the replanted clear-cuts deer and elk heavily rely on for forage.

This sort of benefit is called an "ecosystem service." Deer and elk generally prefer to eat broadleaf and herbaceous vegetation but will eat Douglas-fir seedlings if they're reachable.

Experimental plots in the Coast Range of northwest Oregon - home to some of the most economically productive forests in the world - showed that deer and elk perform that valuable ecosystem service for the Douglas firs, but not under the management conditions the researchers had predicted.

Postdoctoral researcher Thomas Stokely, the study's corresponding author, and Matt Betts, professor in the Department of Forest Ecosystems and Society, hypothesized that if competing vegetation was left untreated by herbicides, the deer and elk would eat it and thus promote growth among the crop trees.

Each of their study parcels reflected a different level of herbicide spraying - none, light, moderate and intensive. To determine what effects deer and elk were having or not having, the parcels included exclosures - areas with tall fencing around them - to keep the animals out.

"What we expected, since deer and elk are often considered plantation pests, is that if we sprayed the broadleaf vegetation and removed their forage initially, they'd do more browsing on crop trees," Stokely said. "And we thought that if we left the broadleaf vegetation untreated, by eating all of those trees and shrubs they'd perform an ecosystem service and actually promote crop tree growth. What we found was the opposite."

Where the vegetation treatment was intensive, deer and elk provided the second part of a 1-2 punch that kept the Douglas-firs' competitors completely under control.

"In the non- and lightly treated areas, we essentially found that the crop trees could not get above browsing height," Stokely said. "There was too much competition - the crop trees were more susceptible to being crowded out and browsed, and the growth of crop trees was less with herbivore access than where they were excluded."

In the moderately treated areas, which reflect common management practice in the Coast Range, it was something of a mixed bag: The deer and elk browsed crop trees "quite a bit" in some instances but did play a positive role in crop tree survival in others. Furthermore, herbaceous forage became more available for deer, indicating plantations can provide both wood for people and food for wildlife.

"Wildlife agencies and managers have gone to great lengths to deter browsing and rarely considered how vegetation management might change herbivore behavior," Stokely said. "Overall, we found the effects of vegetation management for promoting timber production are highly dependent on the presence of large herbivores."

We often find that food becomes rotten when we leave it outside for long and fruits turn brown after they are peeled or cut. Such phenomena can be easily seen in our daily life and they illustrate the oxidation-reduction reaction. The fundamental principle controlling physical properties of two-dimensional materials noted as next generation materials like graphene is found to be redox reactions.

The research team consisted of Professor Sunmin Ryu, Kwanghee Park, and Haneul Kang, affiliated with Department of Chemistry, POSTECH, discovered that the doping of two-dimensional materials with influx of charges from outside in the air is by an electrochemical reaction driven by the redox couples of water and oxygen molecules. Using real-time photoluminescence imaging, they observed the electrochemical redox reaction between tungsten disulfide and oxygen/water in the air. According to their study¸ the redox reaction can control the physical properties of two-dimensional materials which can be applied to bendable imaging element, high-speed transistor, next generation battery, ultralight material and other two-dimensional semiconductor applications.

Two-dimensional materials like graphene and tungsten disulfide are in the form of a single or few layers of atoms in nanometer size. They are thin and easily bended but hard. Because of these properties, they are used in semiconductors, display, solar battery and more and, they are called as a dream material. However, since all atoms exist on the surface of a material, it is limited to the ambient environment such as temperature and humidity which often causes them to modify or transform. Before the research team announced on the result of their study, it has been unknown why such phenomenon happens and has been difficult to commercialize, being unable to control material properties.

The research team used real-time photoluminescence imaging of tungsten disulfide and Raman spectroscopy of graphene. They demonstrated molecular diffusion through the two-dimensional nanoscopic space between two-dimensional materials and hydrophilic substrates. They also discovered that there was enough amount of water to mediate the redox reactions in the space. Furthermore, they proved that charge doping in the acid such as hydrochloric acid is also dictated by dissolved oxygen and hydrogen-ion concentration (pH) in the same way.

What they have accomplished in this research is the fundamental principle needed to govern electrical, magnetic, and optical properties of two-dimensional or other low-dimensional materials. It is anticipated that this method can be applied to improve pretreatment which is needed to prevent two-dimensional materials from being modified by surroundings and aftertreatment technology such as encapsulation for flexible and stretchable displays.

Professor Sunmin Ryu said, "Using the real-time photoluminescence, we were able to demonstrate that the electrochemical reaction driven by the redox couples of oxygen and water molecules in the air is the key and proved the fundamental principle for governing properties of materials. This reaction is applied to not only two-dimensional materials but also other low-dimensional materials such as quantum dot and nanowires. So, our findings will be an important steppingstone to development of nano technology based on low-dimensional materials."

Protein-like molecules called "polypeptoids" (or "peptoids," for short) have great promise as precision building blocks for creating a variety of designer nanomaterials, like flexible nanosheets - ultrathin, atomic-scale 2D materials. They could advance a number of applications - such as synthetic, disease-specific antibodies and self-repairing membranes or tissue - at a low cost.

To understand how to make these applications a reality, however, scientists need a way to zoom in on a peptoid's atomic structure. In the field of materials science, researchers typically use electron microscopes to reach atomic resolution, but soft materials like peptoids would disintegrate under the harsh glare of an electron beam.

Now, scientists at the U.S. Department of Energy's Lawrence Berkeley National Laboratory (Berkeley Lab) have adapted a technique that enlists the power of electrons to visualize a soft material's atomic structure while keeping it intact.

Their study, published in the journal Proceedings of the National Academy of Sciences , demonstrates for the first time how cryo-EM (cryogenic electron microscopy), a Nobel Prize-winning technique originally designed to image proteins in solution, can be used to image atomic changes in a synthetic soft material. Their findings have implications for the synthesis of 2D materials for a wide variety of applications.

"All materials we touch function because of the way atoms are arranged in the material. But we don't have that knowledge for peptoids because unlike proteins, the atomic structure of many soft synthetic materials is messy and hard to predict," said Nitash Balsara, a senior faculty scientist in Berkeley Lab's Materials Sciences Division, and professor of chemical engineering at UC Berkeley, who co-led the study. "And if you don't know where the atoms are, you're flying blind. Our use of cryo-EM for the imaging of peptoids will set a clear path for the design and synthesis of soft materials at the atomic scale."

Taking a hard look at soft materials

For the last 13 years, Balsara has been leading an effort to image soft materials at the atomic scale through Berkeley Lab's Soft Matter Electron Microscopy Program. For the current study, he joined forces with Ronald Zuckermann, a senior scientist in Berkeley Lab's Molecular Foundry who first discovered peptoids almost 30 years ago in his search for new polymers -materials made of long, repeating chains of small molecular units called "monomers" - for targeted drug therapies.

"This study comes out of many years of research here at Berkeley Lab. To make a material and see the atoms - it's the dream of my career," said Zuckermann, who co-led the study with Balsara.

Unlike most synthetic polymers, peptoids can be made to have a precise sequence of monomer units, a common trait in biological polymers, such as proteins and DNA.

And like natural proteins, peptoids can grow or self-assemble into distinct shapes for specific functions - such as helices, fibers, nanotubes, or thin and flat nanosheets.

But unlike proteins, the molecular structure of peptoids is typically amorphous and unpredictable - like a pile of wet noodles. And untangling such an unpredictable structure has long been an obstacle for materials scientists.

Pinning down peptoids with cryo-EM

So the researchers turned to cryo-EM, which flash-freezes the peptoids at a temperature of around 80 kelvins (or minus 316 degrees Fahrenheit) in microseconds. The ultracold temperature of cryo-EM locks in the structure of the sheet and also prevents the electrons from destroying the sample.

To protect soft materials, cryo-EM uses fewer electrons than conventional electron microscopy, resulting in ghostly black-and-white images. To better document what's going on at the atomic level, hundreds of these images are taken. Sophisticated mathematical tools combine these images to make more detailed atomic-scale pictures.

For the study, the researchers fabricated nanosheets in solution from short peptoid polymers made of a chain of six hydrophobic monomers known as "aromatics," connected to four hydrophilic polyether monomers. The hydrophilic or "water-loving" monomers are attracted to the water in the solution, while the hydrophobic or "water-hating" monomers avoid the water, orienting the molecules to form crystalline nanosheets that are only one-molecule thick (around 3 nanometers, or 3 billionths of a meter).

Lead author Sunting Xuan, a postdoctoral researcher in the Materials Sciences Division, synthesized the peptoid nanosheets and used X-ray scattering techniques at Berkeley Lab's Advanced Light Source (ALS) to characterize their molecular structure. The ALS produces light in a variety of wavelengths to enable studies of samples' nanoscale structure and chemistry, among other properties.

Xi Jiang, a project scientist in the Materials Sciences Division, captured the high-quality images and developed the algorithms necessary to achieve atomic resolution in the peptoid imaging.

David Prendergast, senior staff scientist and interim director of the Molecular Foundry, modeled atomic substitutions in the peptoids, and Nan Li, a postdoctoral researcher at the Molecular Foundry, performed molecular dynamics simulations to establish an atomic-scale model of the nanosheet.

At the heart of the team's discovery was their ability to rapidly iterate between materials synthesis and atomic imaging. The precision of peptoid synthesis, coupled with the researchers' ability to directly image the placement of atoms using cryo-EM, allowed them to engineer the peptoid at the atomic level. To their surprise, when they created several new variations of the peptoid monomer sequence, the atomic structure of the nanosheet changed in a very orderly way.

For example, when one additional bromine atom was added to each aromatic ring, the shape of each peptoid molecule remained unchanged yet the space between rows increased by just enough to accommodate the additional bromine atoms.

Furthermore, when four additional variants of the peptoid nanosheet structure were imaged, the researchers noticed a remarkable uniformity across their atomic structure, and that the nanosheets shared the same shape of peptoid molecules. This allowed them to predictably engineer the nanosheet structure, Zuckermann said.

"To have so much control at the atomic scale in soft materials was completely unexpected," said Balsara, because it was assumed that only proteins could form defined shapes when you have a specific sequence of monomers - in their case, amino acids.

A team approach to new materials

For close to four decades, Berkeley Lab has pushed the boundaries of electron microscopy into fields of science once considered impossible to explore with an electron beam. Pioneering work by scientists at Berkeley Lab also played a key role in the 2017 Nobel Prize in chemistry, which honored the development of cryo-EM.

"Most people would say it's not possible to develop a technique that can position and see individual atoms in a soft material," said Balsara. "The only way to solve hard problems like this is to team up with experts across scientific disciplines. At Berkeley Lab, we work as a team."

Zuckermann added that the current study proves that the cryo-EM technique could be applied to a wide range of common polymers and other industrial soft materials, and could lead to a new class of soft nanomaterials that fold into protein-like structures with protein-like functions.

"This work sets the stage for materials scientists to tackle the challenge of making artificial proteins a reality," he said, adding that their study also positions the team to work on solving a diversity of exciting problems, and to "raise people's awareness that they, too, can begin to look at the atomic structure of their soft materials using these cryo-EM techniques."

With many of the products we use every day held together by adhesives, researchers from UBC's Okanagan campus and the University of Victoria hope to make everything from protective clothing to medical implants and residential plumbing stronger and more corrosion resistant thanks to a newly-developed 'hyper glue' formula.

The team of chemists and composite materials researchers discovered a broadly applicable method of bonding plastics and synthetic fibres at the molecular level in a procedure called cross-linking. The cross-linking takes effect when the adhesive is exposed to heat or long-wave UV light making strong connections that are both impact-resistant and corrosion-resistant. Even with a minimal amount of cross-linking, the materials are tightly bonded.

"It turns out the adhesive is particularly effective in high-density polyethylene, which is an important plastic used in bottles, piping, geomembranes, plastic lumber and many other applications," says Professor Abbas Milani, director of UBC's Materials and Manufacturing Research Institute, and the lead researcher at the Okanagan node of the Composite Research Network. "In fact, commercially available glues didn't work at all on these materials, making our discovery an impressive foundation for a wide range of important uses."

UVic Organic Chemistry Professor Jeremy Wulff, whose team led the design of the new class of cross-linking materials, collaborated with the UBC Survive and Thrive Applied Research to explore how it performed in real-world applications.

"The UBC STAR team was able put the material through its paces and test its viability in some incredible applications, including ballistic protection for first responders," says Wulff.

The discovery, he says, is already playing an important role in the Comfort-Optimized Materials for Operational Resilience, Thermal-transport and Survivability (COMFORTS) network, a team of researchers from UBC, UVic and the University of Alberta who are collaborating to create high-performance body armour.

"By using this cross-linking technology, we're better able to strongly fuse together different layers of fabric types to create the next generation of clothing for extreme environments," says Wulff. "At the same time, the cross-linker provides additional material strength to the fabric itself."

Milani is quick to point out that an incredibly strong bonding agent is just the beginning of what it can do.

"Imagine paints that never peel or waterproof coatings that never need to be resealed," says Milani. "We're even starting to think about using it as a way to bond lots of different plastic types together, which is a major challenge in the recycling of plastics and their composites."

"There is real potential to make some of our everyday items stronger and less prone to failure, which is what many chemists and composite materials engineers strive for."

A flotilla of Vietnamese fishing boats with crews suffering in harsh conditions is stripping Pacific coral reefs of seafood as the poaching escalates to become an international human rights and security issue.

Dr Andrew Song, joint ARC Centre of Excellence for Coral Reef Studies and WorldFish research fellow at James Cook University, has produced the first analysis of international attempts to manage Vietnam's 'blue boat' fleet - small fishing vessels, commonly painted blue, that travel thousands of kilometres to fish illegally in Pacific waters.

Dr Song said the reasons are allegedly economic but also geopolitical as the intensified Chinese presence/interference has squeezed them out of their traditional fishing grounds in the South China Sea.

"The boats are between 10-15 metres in length and carry up to 17 people. The crews reportedly have no contract of employment and no insurance and are frequently abandoned after accidents or arrests. They travel more than 7000km around the Pacific and stay up to three months at sea, Dr Song said.

He said their main targets are high-value species of sea cucumber and giant clam found on many Pacific Island coral reefs.

Dr Song estimates the cost of the boats to be around AU$15,000-35,000 each, while processed tropical sea cucumber species can retail at AU$150-300 per kilogram in Hong Kong and Chinese markets. He said there is suspicion that the blue boats were meeting large 'mother-ships' in the open ocean to offload their catch and take on supplies. This is yet to be confirmed.

"The collection of sea cucumber in foreign waters is apparently easier and less dangerous, since sea cucumber is still found six to seven metres deep on Pacific island reefs, whereas people have to dive 60 metres, even 80 metres in waters near Vietnam," Dr Song said.

"The poaching also directly endangers the livelihood security of coastal communities and a significant source of national export revenue in the Pacific. Sea cucumber fisheries are considered to be the second-most valuable export fishery for Pacific Island countries," he said.

Dr Song said Pacific Island countries face limitations in securing the resources to patrol such a vast area, and the wooden boats are difficult to find, even with radar, and harder to trace administratively than a large ship. He said the problem is intensifying.

"In Australian waters, the latest reported figures show the number of foreign fishing boats caught operating illegally has increased from six in 2014 up to 20 in 2016 with most originating from Vietnam and Indonesia," he said.

Dr Song said the poachers can be seen as a new kind of security threat--endangering the lives of Vietnamese fishers, endangering food security for Pacific Island nations, and putting Pacific Island economies, coastal communities and the workers on the boats at risk.

"By their dispersed and random nature, blue boats are bolstering the need for closer cooperation not only among governments and agencies but also among coastal communities and individual fishers.

"Given the large unpredictability associated with these boats, it will need a co-ordinated and networked response," he said.

The percentage of the world's population that is above or below the 'replacement level of fertility' has long been used as a measure of demographic development. A new study revisited how this metric is calculated and how useful it really is in terms of informing policy decisions.

The term "replacement level fertility" is used to describe the total fertility rate of a population--in other words, the average number of children born per woman at which a population exactly replaces itself from one generation to the next without migration. A number of studies have attempted to explore the proportion of the world living in countries where fertility is below replacement rate, as this is seen as a general indicator of the overall demographic development of the world. Most of these studies have used 2.1 as a cut off--meaning that the total number of children born, or that are likely to be born to a woman in her lifetime if she were subject to the prevailing rate of age-specific fertility in the population, is 2.1. The problem, however, is that the replacement fertility for many countries is not 2.1, which implies that using it could be detrimental to the construction of population policies that address contemporary social, economic, and political challenges.

According to IIASA World Population Deputy Program Director, Sergei Scherbov and Stuart Gietel-Basten, a professor of Social Science and Public Policy at the Hong Kong University of Science and Technology, there is a significant range in the total fertility levels that countries need to replace themselves. They say that although it is commonly believed that replacement rates are important and they are often presented as some kind of target, there is actually very little evidence that 2.1 is actually the optimum fertility rate. Rather, the findings indicate that there are many countries in the world where the rate of replacement is greater than 2.1, which is a direct consequence of higher levels of mortality and skewed sex ratios at birth, resulting from sharp gender inequalities. In their paper published in the journal PLOS One, Scherbov and Gietel-Basten endeavored to recalculate the proportion of the world's population living in countries that are either below or above the actual replacement rate in that country. Instead of using the norm of 2.1, however, the authors used the actual replacement rate of different territories--including for the states of India.

"We found that when considering all countries of the world, the majority of people do not live in territories with below replacement fertility. However, when we subdivide India into its constituent states and count them as countries, there is a majority. We also found that the history of the proportion of the world living in below replacement fertility settings in the past, is significantly different when considering actual replacement levels, which were much higher in the past than either today's or the 2.1 figure schedule that is commonly used," explains Gietel-Basten.

The authors note that the study produced unexpected results in terms of the number of people who lived in below replacement fertility populations in the past. More importantly, they clearly show just how much countries really differ from the widely held norm of 2.1. Whether the fertility rate in a country is above or below the replacement rate is not so important. However, the fact that so many countries have a replacement rate of fertility much higher than 2.1 shows how unequal our world is, and how many human lives are lost every year as a result of mortality and inequality. The fact that there is a difference is perhaps more important than the actual degree of the difference at the global level in terms of telling us how much we still have to do to improve mortality rates and remove barriers to gender equality.

"Our paper demonstrates that there are many misunderstandings about replacement level fertility. Scientists have incorrectly represented what replacement fertility actually is and have performed calculations that have been widely cited and which are, quite frankly, inaccurate. At a basic level, it matters that the correct protocol is followed, and that more accurate numbers and information is conveyed to the public," Scherbov concludes.

An international group of scientists, including Andrey Savelyev, associate professor of the Institute of Physical and Mathematical Sciences and Information Technologies of the IKBFU, has improved a computer program that helps simulate the behavior of photons when interacting with hydrogen spilled in intergalactic space. Work results published in the scientific journal Monthly Notices of the Royal Astronomical Society.

Andrey Saveliev said:

"In the Universe there are extragalactic objects such as blazars, which very intensively generate a powerful gamma-ray flux, part of photons from this stream reaches the Earth, as they say, directly, and part - are converted along the way into electrons, then again converted into photons and only then get to us. The problem here is that mathematical calculations say that a certain number of photons should reach the Earth, and in fact it gets much less".

Scientists, according to Andrey Savelyev, today have two versions of why this happens. The first is that a photon, after being converted into an electron (and this, as is known, in contrast to a neutral photon, a charged particle) falls into a magnetic field, deviates from its path and does not reach the Earth, even after being transformed again in the photon.

The second version explains the behavior of particles flying to our planet not by their interaction with an electromagnetic field, but by contact with hydrogen "spilled" in the intergalactic space.

"Many people believe that space is completely empty and that there is nothing between the galaxies. In fact, there is a lot of hydrogen in a state of plasma, that is, in other words, very strongly heated hydrogen - the scientist explains. - And our report is about how particles interact with this plasma. There is a special computer program that calculates models of particle behavior in intergalactic space. We can say that we improved this program by considering several possible options for the development of events in interaction with plasma".

Unfortunately, it is not yet possible to verify the calculations empirically, because people have not yet learned how to create extreme space conditions on Earth, but Andrey Savelyev is sure that someday this will become possible to some extent.

It is important to note that the results of the research, despite the fact that while they are what is called "pure science," can theoretically be applied in practice in the future.

- Plasma - the fourth state of matter (in addition to gas, liquid and solid) - is very difficult for research, - says Andrey Savelyev. - At the same time, humanity has high hopes for it, as a source of cheap and very powerful energy. And our study is a small contribution to the collection of plasma knowledge. Perhaps they will be useful in developing effective nuclear fusion.