Changing lifestyles are causing city workers to ignore the positive experiences of urban green spaces during their working week. A recent study suggests city planners could do more to promote the benefits of going outdoors to city dwellers.

As society changes, it places new demands on its surroundings. New research has found that some EU countries are better able to manage the undesirable expansion of cities, the concept known as ‘urban sprawl’, because they have a flexible spatial planning policy that can easily adapt to changes. Urban sprawl is a term used to describe the expansion of residential suburbs around city centres, driven by peoples’ desire to live in larger houses and the ease of transport made possible by cars.

Congestion charging in Stockholm has become more successful over time, according to a study by Swedish researchers. Although the total cost of a journey that enters the congestion charge zone has fallen in real terms since the charges were first introduced in 2006, there has consistently been around 29% less traffic within the zone, compared with levels in 2005.

The impact of polluted urban soil on trees is highlighted in a recent study from Latvia. The researchers found that high salt levels from de-icing chemicals and nutrient imbalance in soil damaged lime trees growing in the city of Riga.

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The same artificial intelligence technique typically used in facial recognition systems could help improve prediction of hailstorms and their severity, according to a new, National Science Foundation-funded study. Instead of zeroing in on the features of an individual face, scientists trained a deep learning model called a convolutional neural network to recognize features of individual storms that affect the formation of hail and how large the hailstones will be, both of which are notoriously difficult to predict. The promising results highlight the importance of taking into account a storm's entire structure, something that's been challenging to do with existing hail-forecasting techniques.

Image credit: Carlye Calvin

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Needle pricks not your thing? A team of National Science Foundation-funded scientists is developing wearable skin sensors that can detect what's in your sweat. They hope that one day, monitoring perspiration could bypass the need for more invasive procedures like blood draws, and provide real-time updates on health problems such as dehydration or fatigue. In a new paper, the team describes a new sensor design that can be rapidly manufactured using a "roll-to-roll" processing technique that essentially prints the sensors onto a sheet of plastic like words on a newspaper. They used the sensors to monitor the sweat rate, and the electrolytes and metabolites in sweat, from volunteers who were exercising, and others who were experiencing chemically induced perspiration. The new sensors contain a spiraling microscopic tube, or microfluidic, that wicks sweat from the skin. By tracking how fast the sweat moves through the microfluidic, the sensors can report how much a person is sweating, or their sweat rate. The microfluidics are also outfitted with chemical sensors that can detect concentrations of electrolytes like potassium and sodium, and metabolites like glucose.

Image credit: Bizen Maskey/Sunchon National University

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After 16 years of dedicated planning and engineering, scientists at the U.S. Department of Energy's (DOE) Brookhaven National Laboratory have completed a 3.2 gigapixel sensor array for the camera that will be used in the Large Synoptic Survey Telescope (LSST), a massive telescope that will observe the universe like never before. The digital sensor array is composed of about 200 16-megapixel sensors, divided into 21 modules called "rafts." Each raft can function on its own, but when combined, they will view an area of sky that can fit more than 40 full moons in a single image. Researchers will stitch these images together to create a time-lapse movie of the complete visible universe accessible from Chile. Currently under construction on a mountaintop in Chile, LSST is designed to capture the most complete images of our universe that have ever been achieved. The project to build the telescope facility and camera is a collaborative effort among more than 30 institutions from around the world, and it is primarily funded by DOE's Office of Science and the National Science Foundation.

Image credit: SLAC National Accelerator Laboratory

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Earth's magnetic field seems steady and true -- reliable enough to navigate by. Yet, largely hidden from daily life, the field drifts, waxes and wanes. The magnetic North Pole is currently shifting toward Siberia, forcing the Global Positioning System that underlies modern navigation to update its software sooner than expected. Every several hundred thousand years, the magnetic field dramatically shifts and reverses its polarity. Magnetic north flips to the geographic South Pole and, eventually, back again. This reversal has happened countless times over Earth's history, but scientists' understanding of why and how the field reverses is limited. The researchers find that the most recent field reversal 770,000 years ago took at least 22,000 years to complete, several times longer than previously thought. The results call into question controversial findings that some reversals could occur within a human lifetime.

Image credit: Brad Singer

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The Maya of Central America are thought to have been a kinder, gentler civilization, especially compared to the Aztecs of Mexico. At the peak of Mayan culture some 1,500 years ago, warfare seemed ritualistic, designed to extort ransom for captive royalty or to subjugate rival dynasties, with limited impact on the surrounding population. Only later, archeologists thought, did increasing drought and climate change lead to total warfare -- cities and dynasties were wiped off the map in so-called termination events -- and the collapse of the lowland Maya civilization around 1,000 A.D. (or C.E., current era). New evidence unearthed by National Science Foundation-funded researchers call all this into question, suggesting that the Maya engaged in scorched-earth military campaigns -- a strategy that aims to destroy anything of use, including cropland -- even at the height of their civilization, a time of prosperity and artistic sophistication. The finding also indicates that this increase in warfare, possibly associated with climate change and resource scarcity, was not the cause of the disintegration of the lowland Maya civilization.

Image credit: Francisco Estrada-Belli/Tulane

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National Science Foundation-funded engineers have developed a mathematical framework that can turn any sheet of material into any prescribed shape, inspired by the paper craft kirigami (from the Japanese, kiri, meaning to cut and kami, meaning paper). Unlike its better-known cousin origami, which uses folds to shape paper, kirigami relies on a pattern of cuts in a flat paper sheet to change its flexibility and allow it to morph into 3D shapes. Artists have long used this artform to create everything from pop-up cards to castles and dragons. This research follows previous work by the researchers that characterized how origami-based patterns could be used as building blocks to create almost any three-dimensional curved shape. Next the researchers aim to explore how to combine cuts and folds to achieve any shape with a given set of properties, thus linking origami and kirigami.

Image credit: Harvard SEAS

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Many wild southern sea otters in California are infected with the parasite Toxoplasma gondii, yet the infection is fatal for only a fraction of sea otters, which has long puzzled the scientific community. A National Science Foundation-funded study identifies the parasite's specific strains that are killing southern sea otters, tracing them back to a bobcat and feral domestic cats from nearby watersheds. The study marks the first time a genetic link has been clearly established between the Toxoplasma strains in felid hosts and parasites causing fatal disease in marine wildlife. The study's results highlight how infectious agents like Toxoplasma can spread from cat feces on land to the sea, leading to detrimental impacts on marine wildlife.

Image credit: Trina Wood/UC Davis

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A National Science Foundation-funded research has discovered the root cause of why lithium metal batteries fail -- bits of lithium metal deposits break off from the surface of the anode during discharging and are trapped as "dead" or inactive lithium that the battery can no longer access. The discovery challenges the conventional belief that lithium metal batteries fail because of the growth of a layer, called the solid electrolyte interphase (SEI), between the lithium anode and the electrolyte. The researchers made their discovery by developing a technique to measure the amounts of inactive lithium species on the anode -- a first in the field of battery research -- and studying their micro- and nanostructures. The findings could pave the way for bringing rechargeable lithium metal batteries from the lab to the market.

Image credit: University of California - San Diego

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What an animal eats is a fundamental aspect of its biology, but surprisingly, the evolution of diet had not been studied across the animal kingdom until now. Scientists at the University of Arizona report several unexpected findings from taking a deep dive into the evolutionary history of more than one million animal species and going back 800 million years, when the first animals appeared on our planet. The study revealed several surprising key insights: Many species living today that are carnivorous, meaning they eat other animals, can trace this diet back to a common ancestor more than 800 million years ago; A plant-based, or herbivorous, diet is not the evolutionary driver for new species that it was believed to be; Closely related animals tend to share the same dietary category -- plant-eating, meat-eating, or both. This finding implies that switching between dietary lifestyles is not something that happens easily and often over the course of evolution.

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A National Science Foundation-funded study found that Charles Darwin's famous finches defy what has long been considered a key to evolutionary success: genetic diversity. The research on finches of the Galapagos Islands could change the way conservation biologists think about a species' potential for extinction in naturally fragmented populations. Researchers examined 212 tissue samples from museum specimens and living birds. Some of the museum specimens in the study were collected by Darwin himself in 1835. Only one of the extinct populations, a species called the vegetarian finch, had lower genetic diversity compared to modern survivors. Specifically, researchers believe a biological phenomenon called sink-source dynamics is at play in which larger populations of birds from other islands act as a "source" of immigrants to the island population that is naturally shrinking, the "sink." Without these immigrant individuals, the natural population on the island likely would continue to dwindle to local extinction. The immigrants have diverse genetics because they are coming from a variety of healthier islands, giving this struggling "sink" population inflated genetic diversity.

Image credit: Jose Barreiro

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The molecular mechanism used by many bacteria to kill neighboring cells has redundancy built into its genetic makeup, which could allow for the mechanism to be expressed in different environments, say researchers at Penn State and the University of Wisconsin-Madison. Their new study provides insights into the molecular mechanisms of competition among bacteria. "Many organisms, including humans, acquire bacteria from their environment," said Tim Miyashiro, a biochemist and molecular biologist at Penn State and the leader of the research team. "These bacteria can contribute to functions within the host organism, like how our gut bacteria help us digest food. We're interested in the interactions among bacteria cells, and between bacteria and their hosts, to better understand these mutually beneficial symbiotic relationships." Cells of the bioluminescent bacteria Vibrio fisheri take up residence in the light organ of newly hatched bobtail squid. At night, the bacteria produce a blue glow that researchers believe obscures a squid's silhouette and helps protect it from predators. The light organ has pockets, or crypts, in the squid's skin that provide nutrients and a safe environment for the bacteria. "When the squid hatches, it doesn't yet have any bacteria in its light organ," said Miyashiro. "But bacteria in the environment quickly colonize the squid's light organ." Some of these different bacteria strains can coexist, but others can't. "Microbial symbioses are essentially universal in animals, and are crucial to the health and development of both partners," says Irwin Forseth, a program director in the National Science Foundation's Division of Integrative Organismal Systems, which funded the research. "The results from this study highlight the role small genetic changes can play in microbe interactions. Increased understanding will allow us to better predict organisms' performance in changing environments."

Image credit: Andrew Cecere

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Machine learning algorithms can sometimes do a great job with a little help from human expertise, at least in the field of materials science. In many specialized areas of science, engineering and medicine, researchers are turning to machine learning algorithms to analyze data sets that have grown too large for humans to understand. In materials science, success with this effort could accelerate the design of next-generation advanced functional materials, where development now usually depends on old-fashioned trial and error. By themselves, however, data analytics techniques borrowed from other research areas often fail to provide the insights needed to help materials scientists and engineers choose which of many variables to adjust -- and the techniques can't account for dramatic changes such as the introduction of a new chemical compound into the process. In a new study, researchers explain a technique known as dimensional stacking, which shows that human experience still has a role to play in the age of machine intelligence. The machines gain an edge at solving a challenge when the data to be analyzed are intelligently organized based on human knowledge of what factors are likely to be important and related. "When your machine accepts strings of data, it really does matter how you are putting those strings together," said Nazanin Bassiri-Gharb, the paper's corresponding author and a scientist at the Georgia Institute of Technology. "We must be mindful that the organization of data before it goes to the algorithm makes a difference. If you don't plug the information in correctly, you will get a result that isn't necessarily correlated with the reality of the physics and chemistry that govern the materials."

Image credit: Rob Felt/Georgia Tech

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A new study shows that graphene sheets can block the signals mosquitoes use to identify a blood meal, potentially enabling a new chemical-free approach to mosquito bite prevention. Researchers showed that multilayer graphene can provide a twofold defense against mosquito bites. The ultra-thin yet strong material acts as a barrier that mosquitoes are unable to bite through. At the same time, experiments showed that graphene also blocks chemical signals mosquitoes use to sense that a blood meal is near, blunting their urge to bite in the first place. The findings suggest that clothing with a graphene lining could be an effective mosquito barrier.

Image credit: Hurt Lab/Brown University

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A new study shows that the West Antarctic Peninsula is experiencing some of the most rapid climate change on Earth, featuring dramatic increases in temperatures, retreats in glaciers and declines in sea ice. The Southern Ocean absorbs nearly half of the carbon dioxide -- the key greenhouse gas linked to climate change -- that is absorbed by all the world's oceans. The study tapped an unprecedented 25 years of oceanographic measurements in the Southern Ocean and highlights the need for more monitoring in the region. The research revealed that carbon dioxide absorption by surface waters off the West Antarctic Peninsula is linked to the stability of the upper ocean, along with the amount and type of algae present. A stable upper ocean provides algae with ideal growing conditions. During photosynthesis, algae remove carbon dioxide from the surface ocean, which in turn draws carbon dioxide out of the atmosphere. From 1993 to 2017, changes in sea ice dynamics off the West Antarctic Peninsula stabilized the upper ocean, resulting in greater algal concentrations and a shift in the mix of algal species. That's led to a nearly five-fold increase in carbon dioxide absorption during the summertime. The research also found a strong north-south difference in the trend of carbon dioxide absorption. The southern portion of the peninsula, which to date has been less impacted by climate change, experienced the most dramatic increase in carbon dioxide absorption, demonstrating the poleward progression of climate change in the region.

Image credit: Drew Spacht/The Ohio State University

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Many people turn to the Internet to find a Mr. or Ms. Right. But lemurs just give their potential partners a sniff. A study of lemur scents has found that an individual’s distinctive body odor reflects genetic differences in their immune system, and that other lemurs can detect these differences by smell. From just one whiff, these primates can tell which prospective partners have immune genes different from their own. The ability to sniff out mates with different immune genes could make their offspring’s immune systems more diverse and able to fight more pathogens. Shown here: Fritz the ring-tailed lemur sniffs a tree for traces of other lemurs’ scents.

Image credit: David Haring/Duke Lemur Center

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On August 17, 2017, scientists made history with the first direct observation of a merger between two neutron stars. It was the first cosmic event detected in both gravitational waves and the entire spectrum of light, from gamma rays to radio emissions. The impact also created a kilonova -- a turbocharged explosion that instantly forged several hundred planets’ worth of gold and platinum. The observations provided the first compelling evidence that kilonovae produce large quantities of heavy metals, a finding long predicted by theory. Astronomers suspect that all of the gold and platinum on Earth formed as a result of ancient kilonovae created during neutron star collisions. Based on data from the 2017 event, first spotted by the Laser Interferometer Gravitational-wave Observatory (LIGO), astronomers began to adjust their assumptions of how a kilonova should appear to Earth-bound observers. A team of scientists reexamined data from a gamma-ray burst spotted in August 2016 and found new evidence for a kilonova that went unnoticed during the initial observations.

Image credit: NASA/ESA/E. Troja

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Scientists have recovered the first genetic data from an extinct bird in the Caribbean, thanks to the remarkably preserved bones of a Creighton's caracara in a flooded sinkhole on Great Abaco Island in the Bahamas. Studies of ancient DNA from tropical birds have faced two formidable obstacles. Organic material quickly degrades when exposed to heat, light and oxygen. And birds' lightweight, hollow bones break easily, accelerating the decay of the DNA within. But the dark, oxygen-free depths of a 100-foot blue hole known as Sawmill Sink provided ideal preservation conditions for the bones of Caracara creightoni, a species of large carrion-eating falcon that disappeared soon after humans arrived in the Bahamas about 1,000 years ago. Florida Museum of Natural History researcher Jessica Oswald and her colleagues extracted and sequenced genetic material from the 2,500-year-old C. creightoni femur. Because ancient DNA is often fragmented or missing, the team had modest expectations for what they would find –- maybe one or two genes. But instead, the bone yielded 98.7% of the bird's mitochondrial genome, the DNA most living things inherit from their mothers. The mitochondrial genome showed that C. creightoni is closely related to the two remaining caracara species alive today: the crested caracara and the southern caracara. The three species last shared a common ancestor between 1.2 and 0.4 million years ago. "This project enhanced our understanding of the ecological and evolutionary implications of extinction, forged strong international partnerships, and trained the next generation of researchers," says Jessica Robin, a program director in National Science Foundation's Office of International Science and Engineering, which funded the study.

Image credit: Florida Museum photo by Kristen Grace

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National Science Foundation (NSF)-funded researchers from North Carolina State and Elon universities have developed a technique that allows them to remotely control the movement of soft robots, lock them into position for as long as needed and later reconfigure the robots into new shapes. The technique relies on light and magnetic fields. "By engineering the properties of the material, we can control the soft robot's movement remotely; we can get it to hold a given shape; we can then return the robot to its original shape or further modify its movement; and we can do this repeatedly. All of those things are valuable, in terms of this technology's utility in biomedical or aerospace applications," says Joe Tracy, a professor of materials science and engineering at NC State and corresponding author of a paper on the work. In experimental testing, the researchers demonstrated that the soft robots could be used to form "grabbers" for lifting and transporting objects. The soft robots could also be used as cantilevers or folded into "flowers" with petals that bend in different directions. "We are not limited to binary configurations, such as a grabber being either open or closed," says Jessica Liu, first author of the paper and a Ph.D. student at NC State. "We can control the light to ensure that a robot will hold its shape at any point."

Image credit: Jessica A.C. Liu

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How do galaxies such as our Milky Way come into existence? How do they grow and change over time? The science behind galaxy formation has long been a puzzle, but a University of Arizona-led team of scientists is one step closer to finding answers, thanks to supercomputer simulations. Observing real galaxies in space can only provide snapshots in time, so researchers who study how galaxies evolve over billions of years need to use computer simulations. Traditionally, astronomers have used simulations to invent theories of galaxy formation and test them, but they have had to proceed one galaxy at a time. Peter Behroozi of the university's Steward Observatory and colleagues overcame this hurdle by generating millions of different universes on a supercomputer, each according to different physical theories for how galaxies form. The findings challenge fundamental ideas about the role dark matter plays in galaxy formation, the evolution of galaxies over time and the birth of stars. The study is the first to create self-consistent universes that are exact replicas of the real ones -- computer simulations that each represent a sizeable chunk of the actual cosmos, containing 12 million galaxies and spanning the time from 400 million years after the Big Bang to the present day. The results from the "UniverseMachine," as the authors call their approach, have helped resolve the long-standing paradox of why galaxies cease to form new stars even when they retain plenty of hydrogen gas, the raw material from which stars are forged. The research is partially funded by NSF's Division of Physics through grants to UC Santa Barbara's Kavli Institute for Theoretical Physics and the Aspen Center for Physics.

Image credit: NASA/ESA/J. Lotz and the HFF Team/STScI

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Bridges make travel faster and more convenient, but, in an earthquake, these structures are subject to forces that can cause extensive damage and make them unsafe. Now civil and environmental engineer Petros Sideris of Texas A&M University is leading a National Science Foundation (NSF)-funded research project to investigate the performance of hybrid sliding-rocking (HSR) columns. HSR columns provide the same support as conventional bridge infrastructure columns but are more earthquake-resistant. HSR columns are a series of individual concrete segments held together by steel cables that allow for controlled sliding and rocking. This allows the columns to shift without damage, while post-tensioning strands ensure that at the end of an earthquake the columns are pushed back to their original position. Conventional bridges are cast-in-place monolithic concrete elements that are strong but inflexible. Structural damage in these bridge columns, typically caused by a natural disaster, often forces a bridge to close until repairs are completed. But bridges with HSR columns can withstand large earthquakes with minimal damage and require minor repairs, likely without bridge closures. Such infrastructure helps with post-disaster response and recovery and can save thousands in taxpayer dollars. In an earthquake, HSR columns provide "multiple advantages to the public," Sideris said. "By preventing bridge damage, we can maintain access to affected areas immediately after an event for response teams to be easily deployed, and help affected communities recover faster. In mitigating losses related to post-event bridge repairs and bridge closures, more funds can be potentially directed to supporting the recovery of the affected communities." According to Joy Pauschke, NSF program director for natural hazards engineering, "NSF invests in fundamental engineering research so that, in the future, the nation's infrastructure can be more resilient to earthquakes, hurricanes, and other forces of nature."

Image credit: Texas A&M University