Earth

COLUMBUS, Ohio - City living appears to improve reproductive success for migratory tree swallows compared to breeding in more environmentally protected areas, a new five-year study suggests. But urban life comes with a big trade-off - health hazards linked to poorer water quality.

Researchers found that city-dwelling birds bred more nestlings because of warmer local temperatures. But they also had much higher levels of mercury in their blood - presumably from eating insects that spent their larval stages in contaminated water - than their counterparts breeding in less urban areas.

The study was conducted in central Ohio, where scientists observed tree swallows as a model species to assess their breeding success, diet and health measures in the context of varied temperatures, water quality and land use based on the location of their nests.

Despite those specifics, Ohio State University researchers consider the long-term study a harbinger of what's to come for all sorts of wildlife as urbanization increases while the climate continues to warm, and how land-use changes are likely to harm water quality and threaten biodiversity.

Urban land accounts for about 70 million acres in the contiguous United States, representing a 470% increase since 1945.

"With urbanization expanding worldwide, we are transforming the landscape. And this isn't going away," said lead author Mažeika Sullivan, director of the Schiermeier Olentangy River Wetland Research Park at Ohio State. "My lab is looking at how urbanization affects multiple responses of ecosystems - what those changes are and quantifying them, but also seeing what this tells us about how we can manage and conserve ecosystems and wildlife in this context.

"Our task, knowing wildlife are using urban settings, is to think about ways to maximize benefits and minimize the risks. There's nature in cities. So how can we make our cities a little more wild?"

Sullivan, also an associate professor in Ohio State's School of Environment and Natural Resources, completed the work with graduate students Joseph Corra and Jeffry Hayes. The study was published online Nov. 15 in the journal Ecological Monographs.

Tree swallows are part of a guild of birds called aerial insectivores, which do all their dining on insects while in flight. Other species of swallows, as well as whip-poor-wills, nighthawks, swifts, martins and flycatchers, are also part of this group, and many of these species rely on ecosystems near water for food and habitat. Previous research has suggested that the number of North American birds has declined by about 3 billion since 1970, and the populations of some species of aerial insectivores have declined by over 50%.

The magnitude of that loss alone is a striking example of biodiversity loss, Sullivan said. But the reduction in this guild of birds can also affect the economy and the quality of human life.

"These migratory birds are really important not just in and of themselves, but because they're controlling insects - including pest insects that carry disease or damage agricultural crops. So they are very, very important in terms of how ecosystems function and stay in balance," he said.

For research purposes, tree swallows are also useful subjects because they are "cavity nesters" that flocked to the assortment of artificial nest boxes the team constructed along waterways in Columbus, some in developed zones and others in more forested areas.

From 2014-2018, the researchers observed tree swallows during their breeding season, most of May and June each year, also measuring their body weight and blood glucose and mercury levels and tracking how much of the birds' food source came from insects emerging from water or starting their pre-winged life on land. The scientists also monitored temperature and chemical water quality and quantified percentages of forested or wetland versus developed land at the breeding sites.

Egg-laying occurred significantly earlier (by almost eight days), the clutch sizes were larger, and the number of fledglings that left the nest was higher at the urban sites than at protected sites. This reproductive success was largely attributable to the temperature: The air was warmer in urban sites than in protected sites by an average of 3 degrees Fahrenheit, and city locations had fewer extremely cold days.

"We were looking at urbanization in two different ways - as a category of urban versus not urban, but also as gradients of urbanization. As the amount of urbanization increased, fledgling success increased," Sullivan said. "This tells us local climate is extremely important for reproductive success of tree swallows, and likely other insectivorous birds."

But that success came with potential health risks related to poorer water quality in urban areas. Insects that emerge from water constituted roughly a third of the tree swallows' diet, and those insects also tend to provide more nutrition and energy than terrestrial flying insects. But the river water in urban areas had higher levels of mercury - likely a proxy for other contaminants - and the adult birds' blood concentration of mercury was 482% higher in city-dwellers than in those who bred in protected sites.

"This is an important warning," Sullivan said. "There's a whole suite of environmental contaminants out there - pesticides, a lot of other heavy metals. So despite the advantage for breeding in these urban areas, there can be a trade-off in individual health."

These findings, and the implications for birds and other wildlife affected by growing urbanization, suggest that productive urban habitats should be factored in to future municipality planning, he said.

Some top considerations for insectivorous birds, as Sullivan sees it, would be establishing protected green ways, creating nesting habitats and structures to replace lost trees and other parts of the natural landscape, lowering the chances for contaminants to stream into waterways, and protecting wildlife food sources by reducing the use of pesticides and insecticides.

"If we had found that urbanization was negatively affecting tree swallows in all the different measures we used, that would be a very different story," Sullivan said. "But I see some rays of hope here."

A recent review of published studies in non-human mammals examines "sexual disturbance," or male behavior towards a female around mating that can be costly for the female--for example, that might inflict physical harm or cause mother-offspring separation. The findings are published in Mammal Review.

The author, Marcelo H. Cassini, PhD, of the Laboratorio de Biología del Comportamiento, in Argentina, found that sexual disturbance was frequent in 4 of the 32 mammalian orders examined: Primates, Artiodactyla, Carnivora, and Cetacea, which all include species with polygyny (in which a male mates with multiple females). The most common response of females to sexual disturbance was grouping around a dominant male.

The most common expression of sexual conflict around copulation was seen in behaviors associated with female retention attempts that cause minor harm. Research suggests that the most common response of females to sexual disturbance comprises female grouping around a dominant male.

Additional research is needed to see whether sexual disturbance affects the reproductive success of males and females.

"This review suggests that sexual aggression is a rare behavior among the thousands of species of mammals," Dr. Cassini said.

A research team led by Northwestern University engineers and Argonne National Laboratory researchers have uncovered new findings into the role of ionic interaction within graphene and water. The insights could inform the design of new energy-efficient electrodes for batteries or provide the backbone ionic materials for neuromorphic computing applications.

Known for possessing extraordinary properties, from mechanical strength to electronic conductivity to wetting transparency, graphene plays an important role in many environmental and energy applications, such as water desalination, electrochemical energy storage, and energy harvesting. Water-mediated electrostatic interactions drive the chemical processes behind these technologies, making the ability to quantify the interactions between graphene, ions, and charged molecules vitally important in order to design more efficient and effective iterations.

"Every time you have interactions with ions in matter, the medium is very important. Water plays a vital role in mediating interactions between ions, molecules, and interfaces, which lead to a variety of natural and technological processes," said Monica Olvera de La Cruz, Lawyer Taylor Professor of Materials Science and Engineering, who led the research. "Yet, there is much we don't understand about how water-mediated interactions are influenced by nanoconfinement at the nanoscale."

Using computer model simulations at Northwestern Engineering and x-ray reflectivity experiments at Argonne, the research team investigated the interaction between two oppositely charged ions in different positions in water confined between two graphene surfaces. They found that the strength of the interaction was not equivalent when the ions' positions were interchanged. This break of symmetry, which the researchers' dubbed non-reciprocal interactions, is a phenomenon not previously predicted by electrostatic theory.

The researchers also found that the interaction between oppositely charged ions became repulsive when one ion was inserted into the graphene layers, and the other was absorbed at the interface.

"From our work, one can conclude that the water structure alone near interfaces cannot determine the effective electrostatic interactions between ions," said Felipe Jimenez-Angeles, senior research associate in Northwestern Engineering's Center for Computation and Theory of Soft Materials and a lead author on the study. "The non-reciprocity we observed implies that ion-ion interactions at the interface do not obey the isotropic and translational symmetries of Coulomb's law and can be present in both polarizable and non-polarizable models. This non-symmetrical water polarization affects our understanding of ion-differentiation mechanisms such as ion selectivity and ion specificity."

"These results reveal another layer to the complexity of how ions interact with interfaces," said Paul Fenter, a senior scientist and group leader in the Chemical Sciences and Engineering Division at Argonne, who led the study's x-ray measurements using Argonne's Advanced Photon Source. "Significantly, these insights derive from simulations that are validated against experimental observations for the same system."

These results could influence the future design of membranes for selective ion adsorption used in environmental technologies, like water purification processes, batteries and capacitors for electric energy storage, and the characterization of biomolecules, like proteins and DNA.

Understanding ion interaction could also impact advances in neuromorphic computing -- where computers function like human brains to perform complex tasks much more efficiently than current computers. Lithium ion can achieve plasticity, for example, by being inserted in or removing from graphene layers in neuromorphic devices.

"Graphene is an ideal material for devices that transmit signals via ionic transport in electrolytes for neuromorphic applications," said Olvera de la Cruz. "Our study demonstrated that the interactions between intercalated ions in the graphene and physically adsorbed ions in the electrolyte is repulsive, affecting the mechanics of such devices."

The study provides researchers with a fundamental understanding of the electrostatic interactions in aqueous media near interfaces that go beyond water's relationship with graphene, which is crucial for studying other processes in the physical and sciences.

"Graphene is a regular surface, but these findings can help explain electrostatic interactions in more complex molecules, like proteins," said Jimenez-Angeles. "We know that what's inside the protein and the electrostatic charges outside of it matters. This work gives us a new opportunity to explore and look at these important interactions."

New Rochelle, NY, November 16, 2020--Maximizing the efficiency of the adeno-associated virus (AAV) platform for gene therapy is the aim of a new pilot project of the National Institutes of Health (NIH). The NIH Platform Vector Gene Therapy (PaVe-GT) project is reported in the peer-reviewed journal Human Gene Therapy. Click here ( http://doi.org/10.1089/hum.2020.259) to read the full-text article free through December 16, 2020.

"PaVe-GT is an experimental translational science initiative that aims to leverage the power of platform vectors and disease relatedness to help deliver on the promise of gene therapy to patients with rare diseases," states the NIH PaVe-GT team.

Gene therapy, and the introduction of a working copy of a defective gene, can be the solution to curing rare, monogenic diseases caused by recessive mutations leading to a loss of function. The main limiting factor has been the ability to effectively deliver therapeutic genes into target cells. PaVe-GT will use AAV9 as a platform vector to develop gene therapy products for four rare diseases. They will all be manufactured in the same facility using the same production and purification methods. The only difference will be the therapeutic gene payloads.

"The very nature of rare diseases makes it difficult to offer therapy to most patients in the absence of a platform approach like PaVe-GT. Thus, PaVe-GT may 'pave the way' for access to the power of gene therapy for many patients who would otherwise be left out of its therapeutic potential," according to Editor-in-Chief of Human Gene Therapy Terence R. Flotte, MD, Celia and Isaac Haidak Professor of Medical Education and Dean, Provost, and Executive Deputy Chancellor, University of Massachusetts Medical School.

An international team of scientists has defied nature to make diamonds in minutes in a laboratory at room temperature - a process that normally requires billions of years, huge amounts of pressure and super-hot temperatures.

The team, led by The Australian National University (ANU) and RMIT University, made two types of diamonds: the kind found on an engagement ring and another type of diamond called Lonsdaleite, which is found in nature at the site of meteorite impacts such as Canyon Diablo in the US.

One of the lead researchers, ANU Professor Jodie Bradby, said their breakthrough shows that Superman may have had a similar trick up his sleeve when he crushed coal into diamond, without using his heat ray.

"Natural diamonds are usually formed over billions of years, about 150 kilometres deep in the Earth where there are high pressures and temperatures above 1,000 degrees Celsius," said Professor Bradby from the ANU Research School of Physics.

The team, including former ANU PhD scholar Tom Shiell now at Carnegie Institution for Science, previously created Lonsdaleite in the lab only at high temperatures.

This new unexpected discovery shows both Lonsdaleite and regular diamond can also form at normal room temperatures by just applying high pressures - equivalent to 640 African elephants on the tip of a ballet shoe.

"The twist in the story is how we apply the pressure. As well as very high pressures, we allow the carbon to also experience something called 'shear' - which is like a twisting or sliding force. We think this allows the carbon atoms to move into place and form Lonsdaleite and regular diamond," Professor Bradby said.

Co-lead researcher Professor Dougal McCulloch and his team at RMIT used advanced electron microscopy techniques to capture solid and intact slices from the experimental samples to create snapshots of how the two types of diamonds formed.

"Our pictures showed that the regular diamonds only form in the middle of these Lonsdaleite veins under this new method developed by our cross-institutional team," Professor McCulloch said.

"Seeing these little 'rivers' of Lonsdaleite and regular diamond for the first time was just amazing and really helps us understand how they might form."

Lonsdaleite, named after the crystallographer Dame Kathleen Lonsdale, the first woman elected as a Fellow to the Royal Society, has a different crystal structure to regular diamond. It is predicted to be 58 per cent harder.

"Lonsdaleite has the potential to be used for cutting through ultra-solid materials on mining sites," Professor Bradby said.

"Creating more of this rare but super useful diamond is the long-term aim of this work."

Ms Xingshuo Huang is an ANU PhD scholar working in Professor Bradby's lab.

"Being able to make two types of diamonds at room temperature was exciting to achieve for the first time in our lab," Ms Huang said.

The team, which involved University of Sydney and Oak Ridge National Laboratory in the US, have published the research findings in the journal Small.

Bountiful harvests in one location can mean empty water reservoirs and environmental woes far from farmlands. A unique study in this week's Nature Communications examines how food, energy, water and greenhouse gases create a vast front in the battle to feed the planet.

Scientists at Michigan State University (MSU) and colleagues have used new sustainability science tools to understand how the increasingly irrigating farm fields to grow food reverberates through the biggest drivers of sustainability. Further, they show It's not just the farmlands that shoulder environmental impacts. Effects are felt faraway as massive water redirects gobble energy and spew emissions. And the biggest reveal: Sometimes, it's places that have no major stake in the plant-water-eat game that end up paying an environmental price.

"Ensuring food security while safeguarding the environment is one of the greatest challenges for the world today, yet as the world has become so globalized, it is an incredibly complicated process, and misunderstanding it or missing impacts can allow major setbacks in achieving sustainability," said Jianguo "Jack" Liu, MSU Rachel Carson Chair in Sustainability. "We need to deploy the new ways of looking at the world in a way that embraces its complexity."

So, the scientists used the framework of metacoupling, which helps look not only at the irrigated farmlands, but also the massive projects to move water from one region to another. The metacoupling framework allows scientists from many different disciplines look at the interactions between socioeconomics and environmental forces - like climate change, diet change, irrigation technologies, crop planting strategies, water diversion -- both within and across borders.

They used the North China Plain (NCP), which is a major food production region, and the rest of China, which has seen significant spikes in food demand, as a demonstration, as well as one segment of China's massive South-to-North Water Transfer Project. While China was the study site, the authors note these methods for examining sustainability would be applicable in the United States and across the world.

Meeting soaring food demands, the crops - primarily wheat and maize - require massive amounts of water. The world's largest and longest water transfer project in this study draws from Hubei Province's water reserves in southern China. The people in Hubei aren't farmers on the scale in the NCP, nor do they buy a significant portion of their cereal crops from the NCP. They are what the scientists call a "spillover" - meaning they are not direct players in this providing/consuming food network. Yet Hubei lost significant amounts of land and water to the project dedicated to keeping the NCP wet and growing. The water transfer also generated a substantial energy footprint.

The team of scientists took the food supply issue from the simplicity of solving a problem of producing food by transferring water, to a more complex one that recognized the many causes and effects that fan out far beyond the farms and tables.

"This study demonstrates the importance of understanding our increasingly connected world in a way that quantifies the often missed and unrecognized connections involved in feeding the world," said Elizabeth Blood, program director of the National Science Foundation's Ecosystem Science and Dynamics of Integrated Socio-Environmental Systems, which supported the work.

"The world is very focused on solving critical environmental problems," said Zhenci Xu, an MSU research associate and the paper's first author. "We are declaring that we cannot cherry-pick the problem we want to solve because growing crops is about more than irrigation and more about the plot of cropland. You cannot have water at this scale without using energy and changing how land is used. Which then means CO2 emissions are generated, and climate change is exacerbated. We say this is complicated, but it's also an opportunity to help make real change."

The paper calls for policies to help address multiple aspects of environmental impacts in different areas simultaneously affected by the transfer of water. They also note that instead of focusing only on the supply side of the issue - in this case the farmlands - it can be useful to also include consumption-based policies - such as encouraging shifts in diets that depend less on resource-intensive crops.

"We need to get used to looking at the many sides of every issue and be prepared likewise to come forward with many different solutions," Liu said. "We no longer live in a one-issue world."

Nearly 200 years ago, Charles Darwin noted striking diversity among the finches of the Galapagos Islands, and his observations helped him propose the role of natural selection in shaping species. Today, some biologists focus their attention on a related group of birds, the finch-like capuchino seedeaters of South America, and their studies are deepening our understanding of the forces that drive evolution.

In the Proceedings of the Natural Academy of Sciences, Cold Spring Harbor Laboratory Professor Adam Siepel and collaborators at Cornell University and the Herzliya Interdisciplinary Center in Israel use genetic evidence to explain how different species of capuchino seedeaters acquired distinct patterns of coloration. Their findings shed light on the role of selective sweeps--a genetic process in which a naturally occurring variation becomes advantageous and is favored by natural selection--in the emergence of new species.

Capuchino seedeaters are of interest to evolutionary biologists because they have diversified from their common ancestor relatively recently. Each species has characteristic plumage and its own song. Differences are caused by lots of variations in only a few dozen spots in otherwise remarkably similar genomes. These small genetic "islands of differentiation" distinguish each species early in their evolutionary split from one another. Over time, as the species diverge more, researchers expect more of their genomes to change.

A few years ago, Leo Campagna and Irby Lovette at Cornell determined that many of these islands affected pigment production genes. In the current study, Siepel's group collaborated with Campagna and Lovette to identify additional differentiation sites and investigate their causes.

Two different genetic processes can create islands of differentiation: selective sweeps or a genetic incompatibility limiting the passage of specific segments of DNA within a population. Computational tools developed in Siepel's lab allowed his team, led by postdoctoral researcher Hussein Hejase, to discriminate between these possibilities. Comparing the genomes of 60 birds from five species confirmed that most of the islands of differentiation that separate today's seedeater species arose due to selective sweeps.

Notably, Siepel explained, most of these appear to be due to soft selective sweeps:

"The soft sweep acts on a variant that already exists in the population. But that variant newly becomes under selective pressure, maybe because of a change of environment, a new predator, a new food, whatever. Or in this case, we think in many cases because of sexual selection, because the birds of the opposite sex found some aspect of that variant attractive, whether it's its coloration or song, and that helped push it to high frequency."

Siepel said the finding shows that even quite striking islands of genetic differentiation can be explained by soft sweeps that acted separately on newly emerging species.

During a 2016 National Oceanic and Atmospheric Administration (NOAA) expedition to explore a pair of World War II shipwrecks that lie off the North Carolina coast, marine scientists ensconced within glass-domed submersibles navigated to the Atlantic Ocean seafloor in the hope of profiling the fish communities residing on the wrecks. Some of the findings of this joint ecological-archaeological undertaking were published this week in the Ecological Society of America's journal Ecosphere.

The two ships, a German U-boat and a Nicaraguan freighter, had not been seen by humans since they sank nearly 80 years ago during the Battle of the Atlantic. "These World War II shipwrecks are important historical monuments, but are also valuable habitat for fish," said Katrina Johnson, the paper's first author and a senior at Bates College in Lewiston, Maine.

Johnson, who grew up spending summers on a small Connecticut island only accessible by boat, jumped at the opportunity to join the research team analyzing the data gathered during the 2016 joint mission, even though she was not able to participate in the mission herself. The expedition team - led by the paper's other coauthors - had fitted the manned submersibles with advanced video and laser scanning equipment, which elicited high-definition three-dimensional imagery requiring extensive processing and analyzing. The project lent itself well to Johnson's long-standing interest in the underwater world, and she, like the rest of the team, was surprised by the extent of fish life thriving on the wrecks.

According to Avery Paxton, Ph.D., a co-author on the study and a research associate at the NOAA National Centers for Coastal Ocean Science (NCCOS) in Beaufort, N.C., the findings raise questions about how fish find these remote sites in the first place. "Since the shipwrecks are such small islands of habitat on the sandy seafloor, it was surprising to see so many large-bodied groupers, like snowy and Warsaw grouper, occupying the shipwrecks," Paxton said. "This phenomenon warrants further study to determine how common this may be in other deep habitats."

The researchers used lasers to acquire 3D snapshots of fish to a millimeter level of precision. For instance, the detailed photos allowed the team to measure the size of a grouper hovering beside the rivet of the U-boat's hull or to document the position of a wreckfish beside the barrel of the deck gun. 

For fish community ecologists, these kinds of details are essential. They can explain why fish populations decide to call a shipwreck home rather than a rocky reef, for example, and whether the thousands of shipwrecks and other submerged human-made structures scattered on the ocean floor could serve as a significant source of fish habitat in the future.

"Seeing so many large predators on such a relatively small habitat begs the question of how and whether they are feeding on these sites," said Chris Taylor, Ph.D., a research ecologist at NCCOS and a co-author of the study. "We know some related species aggregate in very large numbers to spawn, and some species like Goliath grouper tend to aggregate on artificial habitats.  But we don't think that's happening here."

The success of the joint archaeological-ecological mission has opened the door to additional collaborative ventures, which could potentially be carried out by unmanned underwater vehicles in the future.

WASHINGTON, November 17, 2020 -- Pandemics are fueled, in part, by dense populations in large cities where networks of buildings, crowded sidewalks, and public transportation force people into tighter conditions. This contrasts with conditions in rural areas, where there is more space available per person.

According to common sense, being in less crowded areas during a pandemic is safer. But small town mayors want to keep people safe, too, and migration of people from cities to rural towns brings concerns. During the COVID-19 pandemic, closing national borders and borders between states and regions has been prevalent. But does it really help?

In a paper published in Chaos, by AIP Publishing, two researchers decided to put this hypothesis to the test and discover if confinement and travels bans are really effective ways to limit the spread of a pandemic disease. Specifically, they focused on the movement of people from larger cities to smaller ones and tested the results of this one-way migration.

"Instead of taking mobility, or the lack of mobility, for granted, we decided to explore how an altered mobility would affect the spreading," author Massimiliano Zanin said. "The real answer lies in the sign of the result. People always assume that closing borders is good. We found that it is almost always bad."

The model used by the authors is simplified, without many of the details that affect migration patterns and disease spread. But their focus on changes in population density indicates travel bans might be less effective than migration of people to less dense areas. The result was reduced spread of disease.

Zanin and collaborator David Papo placed a hypothetical group of people in two locations and assumed their travel was in random movement patterns. They used SIR dynamics, which is common in epidemiological studies of disease movement. SIR stands for susceptible, infected, and recovered -- classifications used to label groups in a simulation and track disease spread according to their interactions.

They ran 10,000 iterations of the simulation to determine the resulting disease spread among people in two locations when migration is one way: from dense cities to less dense towns. They also studied the effect of "forced migration," which moves healthy people out of dense cities at the onset of a pandemic.

The results showed that while movement from big cities to small towns might be slightly less safe for the people in small towns, overall, for a global pandemic situation, this reduction in the density of highly populated areas is better for the majority of all people.

DURHAM, N.C. -- More than three decades after they were found to have elevated blood lead levels as children, a group of middle-aged adults were found to have some small but significant changes in brain structure that corresponded to their dose of lead exposure in early life.

MRI scans at age 45 revealed some small but significant changes in the brains of the people who had higher lead exposures measured at age 11.

For each 5 micrograms per deciliter more lead they carried as children, the study participants lost an average of 2 IQ points by age 45. They also had slightly more than 1 square centimeter less cortical surface area and 0.1 cubic centimeter less volume in the hippocampus, which plays a role in memory, learning and emotions.

Participants with the highest childhood lead exposures also demonstrated structural deficits in the integrity of their brains' white matter, which is responsible for communication between brain regions.

The research participants themselves reported no loss of cognitive abilities, but people close to them said otherwise, noting that they tended to display small everyday problems with memory and attention, such as getting distracted or misplacing items.

"We find that there are deficits and differences in the overall structure of the brain that are apparent decades after exposure," said Duke University doctoral candidate Aaron Reuben, who is a co-first author on the study, which appears Nov. 17 in the Journal of the American Medical Association. "And that's important because it helps us understand that people don't seem to recover fully from childhood lead exposure and may, in fact, experience greater problems over time."

"All of our brain measures were selected based on previous associations with age-related decline and cognition," said Duke doctoral candidate Maxwell Elliott, co-first author of the study. "Cortical surface area has one of the strongest relationships with cognitive functioning."

The findings come from a long-term study of more than 1,000 people born in the same town in New Zealand in 1972 and 1973 who have been studied nearly continuously since. For this study, the researchers had childhood lead exposure data for 564 of the study participants, who grew up during the peak era of leaded gasoline, which ran from the late-1960's to the late-1980s. As was true across the developed world during that time, almost all of the study participants were exposed to higher lead levels than are permitted today.

"Our findings involve gross features of how your brain looks as a whole," explained Terrie Moffitt, the Nannerl O. Keohane distinguished professor of psychology & neuroscience at Duke and senior author on the paper. "Our research started by looking at these features of the brain because scientists don't really know a whole lot about childhood lead exposure and the brain later in life."

But the differences are there. Elliott said they may reflect long-term consequences of lead exposure, since the cortical surface area, hippocampal volume and white matter structure all grow during childhood and peak in early adulthood.

More differences may emerge as these people age, Reuben said.

It's probably too soon to tell with this well-studied group of middle-aged New Zealanders, but what Reuben would eventually like to understand is whether individuals exposed to lead in childhood may be at greater risk for degenerative disease as they enter older age.

Animal studies have shown that early exposure to lead may lead to brain changes that contribute to degeneration, such as different gene expression patterns and poorer vascular health. But this hasn't been shown yet in humans, Reuben said.

Washington, November 17, 2020--New research finds that student exposure to violent crime in urban elementary schools is linked to higher transfer rates, with students ineligible for free- or reduced-price meals and students from safer neighborhoods more likely to leave than their less advantaged peers. The study was published today in the American Educational Research Journal, a peer-reviewed journal of the American Educational Research Association.

The study, conducted by Julia Burdick-Will, Kiara Millay Nerenberg, and Jeffrey Grigg at Johns Hopkins University, and Faith Connolly at McREL International, analyzed student data from Baltimore City Public Elementary Schools and crime data from the Baltimore Police Department, for academic years 2010-11 to 2015-16, to examine the impact of violent crime during the school year on the likelihood of school exit the following summer. The authors looked at the effect of violent crime that happened on school grounds or the streets immediately surrounding a school between 6 a.m. and 7 p.m. on weekdays during the academic year.

"Our findings offer evidence that school instability is related to high levels of urban violence, and that the effects of violence are more widespread than just the impact on victims, witnesses, or perpetrators," said Burdick-Will, an assistant professor of sociology and education at Johns Hopkins University. "Changing schools is stressful and often harmful to learning under the best of circumstances and when motivated by safety concerns might be even more difficult for students."

"Instability and student churning plagues many urban districts, and these findings underscore how difficult it is for schools to function in an environment where many students and families are exposed to frequent violence," said Burdick-Will.

The study found that for the average student, when school violent crime during the school year doubles from the previous year, there is a 4 percent increase in the odds of school transfer. For students who do not receive free or reduced-priced meals and those who are from the safest 10 percent of neighborhoods in a school district, a doubling of violent crime predicts an 11 percent increase in the odds of school transfer. For students from the most violent neighborhoods, a doubling of the school violent crime rate results in less than a 2 percent increase in the odds of transfer.

"This suggests that more advantaged students are more sensitive to exposure to violence at school and are more able to respond to changes in school violence because of greater access to social and economic resources," said Burdick-Will.

"Large numbers of students without the resources needed to navigate a school transfer are likely to feel unsafe and want to change schools, but are unable to do so," said Burdick-Will. "These students are at a substantial disadvantage, given the negative effect of violence exposure on cognitive functioning and learning."

During the study period, Baltimore's 129 public elementary schools reported an average of approximately eight violent crimes a year, although the distribution is skewed by a few schools that reported more than 50 violent crimes in a single school year. Most schools did not have any of the most serious reported types of crime, but there were a few schools that had up to three homicides and two rapes or shootings in one school year.

The authors caution that violent crime rates at schools can fluctuate dramatically from year to year and that what happens in one year does not necessarily predict what will happen in the next year. Twenty-three percent of the school-years studied showed an increase in violent crime of at least 100 percent from one year to the next.

"Some students may leave one school because they experienced violence for another that they think is safer, only to find that in the next year their new school experiences more violence than expected," Burdick-Will said. "In this case, students might be inclined to move again in the following year, leading to even more instability in their academic trajectories."

The average elementary school could have expected 1.5 students to transfer per year due to safety concerns, according to the study, with the number reaching as high as 9 students per year at some schools. At the district level, an estimated 665 students changed schools during the study period due to exposure to violence. The authors note that Baltimore's violent crime rates have increased since the years analyzed in their study.

"Overall violence in the whole neighborhood around a school is not the same as violence in or next to a school," said Burdick-Will. "Students are much more sensitive to what happens on school grounds or on the streets immediately surrounding the school."

"This means that creating a safe school environment could reduce violence-related transfers even in a larger neighborhood with high crime rates," Burdick-Will said. "By focusing on providing a safe zone immediately around a school, administrators and policymakers can potentially increase stability in enrollment patterns at the district level."

The authors note that turnover in the student population can undermine a school's effort to properly sequence materials and to create the trusting, positive climate necessary for learning, negatively impacting both mobile and non-mobile students. Losing students can also create serious financial and even existential problems for a school.

"Considering the average amount of spending per student allocated by school districts, the loss of a few students can lead to reduced staff and program cuts," Burdick-Will said. "In an era when school funding depends on the number of students in a school, it is especially important to understand why students leave and what can be done to stabilize and increase enrollments."

Animals that migrate "live fast and die young", new research shows.

University of Exeter scientists studied almost 1,300 mammal and bird species and found migrants generally develop faster, produce offspring earlier and die younger than similar, non-migratory species.

The researchers also found that walking and swimming migrants are usually larger than their non-migrating relatives, while flying migrants are smaller.

The findings may partly explain why many migratory species are in decline, as "faster" lives may make them less able to adapt to changes in habitats and the climate - for example, by delaying breeding if conditions are poor.

"Many species migrate over long distances and this requires substantial amounts of energy," said lead author Dr Andrea Soriano-Redondo.

"This energy cannot be used for other purposes such as self-maintenance or reproduction, so we would expect animals to adjust the amount of energy they use for these things.

"By prioritising reproduction over survival, 'fast-living' species have the potential to increase numbers more rapidly - which may balance the long-term energy costs and short-term risks of migrating."

The study examined "pace of life" for 1,296 species based on seven measures, including longevity, age at female sexual maturity and how many times a species can attempt to breed each year.

The researchers say their findings will help predict the responses of bird and mammal species to environmental change, and partly explain the decline of many migratory species.

"We have long thought that migration is a risky behaviour," said Professor Stuart Bearhop, of the Centre for Ecology and Conservation on Exeter's Penryn Campus in Cornwall.

"Animals often take a chance when they migrate, hoping to find the right conditions in their destination.

"In the case of birds that migrate to the High Arctic, they arrive in spring and have a short window in which to breed.

"Some will only attempt this if conditions are right - and if climate change degrades habitats, these 'fast-living' species might miss their chance entirely."

Professor Dave Hodgson added: "We think that walking and swimming migrants are generally larger because only large animals can store enough energy, and use it efficiently enough, to make long-distance land or sea migrations viable.

"Among flying species, the opposite is true, as a large body mass makes flying more costly in terms of energy."

During cell division, a parent cell divides into two daughter cells. Their new role and function depend on the orientation of the division plane. A crucial factor guiding this division orientation is the shape of the mother cell. Now, Professor Carl-Philipp Heisenberg and Benoit Godard, a Postdoc in the Heisenberg lab, discovered - in collaboration with the McDougal lab at Sorbonne University - that the dividing cell softens and thus becomes deformable by mechanical tension originating from neighboring cells, thereby explaining how tissue tension influences cell division orientation.

"The neighboring tissue pulls and deforms the soft dividing cells. Consequently, this alters its cell division orientation and, therefore, the fate of its daughters," explains Carl-Philipp Heisenberg.

A new model organism

Investigating cellular interactions within a tissue is challenging. Due to the large number of cells involved, cause and effect are hard to disentangle. Therefore, Carl-Philipp Heisenberg utilized a unique model organism. Ascidians, small marine invertebrates, develop nearly identical to vertebrates but only consist of very few cells. Additionally, the cell's fate is set quite early. With fewer cells and a predetermined development, ascidians allow scientists to investigate the tissue dynamics more precisely.

Observing dynamics cell shaping

It is known for more than a century that cells tend to divide perpendicular to their long axis. Previously, cells undergoing division were thought to be stiff and thus insensitive to mechanical forces from their environment affecting their shape and thus division orientation. Opposite to these beliefs, Carl-Philipp Heisenberg and his team now discovered that dividing cells can become softer and thus deformable by extrinsic forces.

"We had preliminary and indirect results suggesting that dividing cells become soft, but this was opposite to the literature on cell division. Thus, when I conducted the biophysical measurement of cell stiffness and saw the softening occurring, it was the greatest moment in my scientific career," remembers Benoit Godard

By performing a three-dimensional scan of the cell shapes in the developing ascidian embryos and combining it with biophysical measurements of cell stiffness, the scientists found that dividing cells became softer and, consequently, deformed in response to forces from neighboring cells.

"We wanted to identify the governing factors of cell division. We found that cells become soft when undergoing division and that this allows extrinsic mechanical forces to influence the shape and thus division orientation of the dividing cell," summarizes Carl-Philipp Heisenberg.

This study opens the path to novel fundamental research but might also be relevant for clinical studies. For example, tumors change tissue tension, which again likely influences tumor cells' rate and division orientation. These results help to explain tissue malformation and might enable external controlled tissue formation.

In the past decades, cancer has surpassed many other diseases to become the current second leading cause of death globally, with one in six people dying from it. This concerning position has given it a unique and ubiquitous position in global culture, so much so that finding a cure for cancer is considered one of the most noble things any person can do. Sadly, humanity hasn't arrived at this cure yet; tons of research is being conducted to explore every angle of cancer, trying to find a weakness.

A group of scientists from the Tokyo University of Science, led by Prof Kouji Kuramochi, has also been dedicated to this mission. In their search for a weapon against cancer, they turned to a specific set of organic compounds called "phenazines." Phenazines are a large group of nitrogen-containing "heterocycles" (or compounds with a ring structure composed of at least two different elements). More than a hundred phenazine compounds are found naturally, and over 6000 can be "synthesized." Of these, N-alkylphenazin-1-ones (phenazinones) are a minor group of phenazines that are known to have antibacterial, antifungal, and cytotoxic activities. Cytotoxicity is an exciting property in cancer research, because, if we can "direct" cytotoxic compounds to work against cancer cells, we can eliminate the cancer.

"Pyocyanin, lavanducyanin, lavanducyanin-derived WS-9659 A, WS-9659 B, and marinocyanins A and B, all different types of phenazines, show cytotoxic activities, against cancer cells. However, these compounds are difficult to derive from their natural sources such as bacteria," reports Prof Kuramochi.

Determined to shed more light on them and harness their properties for good, the scientists experimented with synthesizing these compounds through several methods. They performed "halogenation" (the process of adding halogens like chlorine and bromine) and "oxidative condensation" (or addition of an oxidant and a water molecule) on various compounds.

Their strategy succeeded in the highly efficient and selective synthesis of N-alkyl-2-halophenazin-1-ones. Of all the synthesized compounds, they found that 2-chloropyocyanin exhibited high cytotoxicity toward the lung cancer cells. Their findings published in American Chemical Society Omega, explain the logistics of their study in full technical detail.

Prof Kuramochi believes that their discovery also has a beneficial effect on the living world. "We have established a highly versatile synthetic method that is simple and can be applied to the synthesis of many natural products," he says. Since the oxidative coupling reaction proceeds only with oxygen, it is an environmentally friendly synthetic method."

What's more, this novel technique overcomes one of the main drawbacks of the existing techniques. The traditional chlorination of N-alkylphenazin-1-ones with selectively occurs at the 4-position, meaning that the compounds that form out of that reaction are the undesired N-alkyl-4-chlorophenazin-1-ones. This novel synthesis technique overcomes this issue, and allows, for the first time, the synthetic production of WS-9659 B!

Prof Kuramochi and his team look forward to verifying the effects of phenazinones in animal studies and clinical trials. In the development of anticancer drugs, drugs that have little effect on normal cells and act selectively on cancer cells are ideal drug candidates with few side effects.

These new compounds are more than four times more selectively toxic to cancer cells than normal cells. Only time will truly tell if this is the new door opening to the elusive cure for cancer, but this is a sure and definite step in the right direction.

Researchers from Skoltech and their colleagues from Germany and the US have studied the properties and behavior of a palladium-copper alloy under changing temperatures and hydrogen concentrations, with highly relevant implications of this research for catalyst design. The paper was published in the Journal of Applied Physics.

Transition metal-alloy materials can have catalytic properties and are widely used in facilitating various chemical reactions such as CO2 hydrogenation, a process that turns carbon dioxide into methanol. Using an alloy of a more expensive reactive element with another one that is cheaper and more inert makes these catalysts highly efficient. One example of such a catalyst would be an alloy of palladium (Pd) and copper (Cu), where isolated atoms of Pd are positioned in the Cu lattice.

Zhong-Kang Han, Debalaya Sarker and Sergey Levchenko of the Skoltech Center for Energy Science and Technology (CEST) and their colleagues modeled the properties of a Pd/Cu alloy, using a machine-learning model to predict the distribution of Pd atoms on a Cu surface as a function of hydrogen partial pressure and temperature. "Only Pd atoms at the surface provide catalytically active sites. Therefore, it is important to know how many of these atoms can be found at the surface at relevant temperatures and hydrogen partial pressures," Levchenko says.

He says that evaluating the energies of many atomic configurations of Pd within the Cu lattice requires a lot of computational resources, so the researchers chose a surrogate cluster expansion model that is easier to handle. "This model allows us to evaluate the energy of millions of configurations in seconds. In this study, we had a system that is more complex than the ones typically studied using cluster expansion: a surface of an alloy where the stability of various atomic configurations is influenced by adsorbates from the gas phase. Therefore, we applied the machine-learning approach based on compressed sensing (a method widely used to compress images) to develop a very accurate and predictive surrogate model," Levchenko notes.

The team found that hydrogen adsorption indeed has a strong effect on the concentration of Pd atoms in the top layer of Cu (111) surface. "While at low hydrogen partial pressures and higher temperatures Pd prefers to stay at the surface, at higher pressures and lower temperatures hydrogen adsorption drives Pd away from the surface," Levchenko explains.

The authors hope that their findings can open the door for designing metal alloys with better catalytic properties by taking into account dynamic changes in the composition and structure of materials at realistic operational conditions.