Photos may improve understanding of volcanic processes

PENN STATE

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VIDEO: A TEAM OF PENN STATE RESEARCHERS STUDIED TELICA VOLCANO, A PERSISTENTLY ACTIVE VOLCANO IN WESTERN NICARAGUA, TO BOTH OBSERVE AND QUANTIFY SMALL-SCALE INTRA-CRATER CHANGE ASSOCIATED WITH BACKGROUND AND ERUPTIVE ACTIVITY... view more 

CREDIT: PENN STATE

The shape of volcanoes and their craters provide critical information on their formation and eruptive history. Techniques applied to photographs -- photogrammetry -- show promise and utility in correlating shape change to volcanic background and eruption activity.

Changes in volcano shape -- morphology -- that occur with major eruptions are quantifiable, but background volcanic activity, manifesting as small volume explosions and crater wall collapse, can also cause changes in morphology and are not well quantified.

A team of Penn State researchers studied Telica Volcano, a persistently active volcano in western Nicaragua, to both observe and quantify small-scale intra-crater change associated with background and eruptive activity. Geologists consider Telica 'persistently' active because of its high levels of seismicity and volcanic degassing, and it erupts on less than 10-year time periods.

The team used direct observations of the crater, photographic observations from 1994 to 2017 and photogrammetric techniques on photos collected between 2011 and 2017 to analyze changes at Telica in the context of summit crater formation and eruptive processes. They used structure-from-motion (SfM), a photogrammetric technique, to construct 3D models from 2D images. They also used point cloud differencing, a method used to measure change between photo sampling periods, to compare the 3D models, providing a quantitative measure of change in crater morphology. They reported their results in Geochemistry, Geophysics, Geosystems.

"Photos of the crater were taken as part of a multi-disciplinary study to investigate Telica's persistent activity," said Cassie Hanagan, lead author on the study. "Images were collected from our collaborators to make observations of the crater's features such as the location and number of fumaroles or regions of volcanic degassing in the crater. For time periods that had enough photos, SfM was used to create 3D models of the crater. We could then compare the 3D models between time periods to quantify change."

Using the SfM-derived 3D models and point cloud differencing allowed the team to quantify how the crater changed through time.

"We could see the changes by visually looking at the photos, but by employing SfM, we could quantify how much change had occurred at Telica," said Peter La Femina, associate professor of geosciences in Penn State's Department of Geosciences. "This is one of the first studies to look at changes in crater morphology associated with background and eruptive activity over a relatively long time span, almost a 10-year time period."

Telica's morphological changes were then compared to the timing of eruptive activity to investigate the processes leading to crater formation and eruption.

Volcanoes erupt when pressure builds beyond a breaking point. At Telica, two mechanisms for triggering eruptions have been hypothesized. These are widespread mineralization within the underground hydrothermal system that seals the system and surficial blocking of the vent by landslides and rock fall from the crater walls. Both mechanisms could lead to increases in pressure and then eruption, according to the researchers.

"One question was whether or not covering the vents on the crater floor could cause pressure build up, and if that would cause an explosive release of this pressure if the vent were sufficiently sealed," said Hanagan.

Comparing the point cloud differencing results and the photographic observations indicated that vent infill by mass wasting from the crater walls was not likely a primary mechanism for sealing of the volcanic system prior to eruption.

"We found that material from the crater walls does fall on the crater floor, filling the eruptive vent," said La Femina. "But at the same time, we still see active fumaroles, which are vents in the crater walls where high temperature gases and steam are emitted. The fumaroles remained active even though the talus from the crater walls covered the vents. This suggests that at least the deeper magma-hydrothermal system is not directly sealed by landslides."

The researchers further note that crater wall material collapse is spatially correlated to where degassing is concentrated, and that small eruptions blow out this fallen material from the crater floor. They suggest these changes sustain a crater shape similar to other summit craters that formed by collapse into an evacuated magma chamber.

"What we found is that during the explosions, Telica is throwing out a lot of the material that came from the crater walls," said La Femina. "In the absence of magmatic eruptions, the crater is forming through this background process of crater wall collapse, and the regions of fumarole activity collapse preferentially."

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The team collaborated with Mel Rogers, assistant research professor at the University of South Florida. Hanagan, now a graduate student at the University of Arizona, completed this research as part of her Schreyer Honors College honors thesis and Department of Geosciences senior thesis.

The National Science Foundation and NASA PA Space Grant WISER program fellowship partially funded this research.

Plato was right. Earth is made, on average, of cubes

The ancient Greek philosopher was on to something, researchers found

UNIVERSITY OF PENNSYLVANIA

 

IMAGE: THE RESEARCH TEAM MEASURED AND ANALYZED FRAGMENTATION PATTERNS OF ROCKS THEY COLLECTED AS WELL AS FROM PREVIOUSLY ASSEMBLED DATASETS. view more 

CREDIT: COURTESY OF GABLOR DOMOKOS AND DOUGLAS JEROLMACK

Plato, the Greek philosopher who lived in the 5th century B.C.E., believed that the universe was made of five types of matter: earth, air, fire, water, and cosmos. Each was described with a particular geometry, a platonic shape. For earth, that shape was the cube.

Science has steadily moved beyond Plato's conjectures, looking instead to the atom as the building block of the universe. Yet Plato seems to have been onto something, researchers have found.

In a new paper in the Proceedings of the National Academy of Sciences, a team from the University of Pennsylvania, Budapest University of Technology and Economics, and University of Debrecen uses math, geology, and physics to demonstrate that the average shape of rocks on Earth is a cube.

"Plato is widely recognized as the first person to develop the concept of an atom, the idea that matter is composed of some indivisible component at the smallest scale," says Douglas Jerolmack, a geophysicist in Penn's School of Arts & Sciences' Department of Earth and Environmental Science and the School of Engineering and Applied Science's Department of Mechanical Engineering and Applied Mechanics. "But that understanding was only conceptual; nothing about our modern understanding of atoms derives from what Plato told us.

"The interesting thing here is that what we find with rock, or earth, is that there is more than a conceptual lineage back to Plato. It turns out that Plato's conception about the element earth being made up of cubes is, literally, the statistical average model for real earth. And that is just mind-blowing."

The group's finding began with geometric models developed by mathematician Gábor Domokos of the Budapest University of Technology and Economics, whose work predicted that natural rocks would fragment into cubic shapes.

"This paper is the result of three years of serious thinking and work, but it comes back to one core idea," says Domokos. "If you take a three-dimensional polyhedral shape, slice it randomly into two fragments and then slice these fragments again and again, you get a vast number of different polyhedral shapes. But in an average sense, the resulting shape of the fragments is a cube."

Domokos pulled two Hungarian theoretical physicists into the loop: Ferenc Kun, an expert on fragmentation, and János Török, an expert on statistical and computational models. After discussing the potential of the discovery, Jerolmack says, the Hungarian researchers took their finding to Jerolmack to work together on the geophysical questions; in other words, "How does nature let this happen?"

"When we took this to Doug, he said, 'This is either a mistake, or this is big,'" Domokos recalls. "We worked backward to understand the physics that results in these shapes."

Fundamentally, the question they answered is what shapes are created when rocks break into pieces. Remarkably, they found that the core mathematical conjecture unites geological processes not only on Earth but around the solar system as well.

"Fragmentation is this ubiquitous process that is grinding down planetary materials," Jerolmack says. "The solar system is littered with ice and rocks that are ceaselessly smashing apart. This work gives us a signature of that process that we've never seen before."

Part of this understanding is that the components that break out of a formerly solid object must fit together without any gaps, like a dropped dish on the verge of breaking. As it turns out, the only one of the so-called platonic forms--polyhedra with sides of equal length--that fit together without gaps are cubes.

"One thing we've speculated in our group is that, quite possibly Plato looked at a rock outcrop and after processing or analyzing the image subconsciously in his mind, he conjectured that the average shape is something like a cube," Jerolmack says.

"Plato was very sensitive to geometry," Domokos adds. According to lore, the phrase "Let no one ignorant of geometry enter" was engraved at the door to Plato's Academy. "His intuitions, backed by his broad thinking about science, may have led him to this idea about cubes," says Domokos.

To test whether their mathematical models held true in nature, the team measured a wide variety of rocks, hundreds that they collected and thousands more from previously collected datasets. No matter whether the rocks had naturally weathered from a large outcropping or been dynamited out by humans, the team found a good fit to the cubic average.

However, special rock formations exist that appear to break the cubic "rule." The Giant's Causeway in Northern Ireland, with its soaring vertical columns, is one example, formed by the unusual process of cooling basalt. These formations, though rare, are still encompassed by the team's mathematical conception of fragmentation; they are just explained by out-of-the-ordinary processes at work.

"The world is a messy place," says Jerolmack. "Nine times out of 10, if a rock gets pulled apart or squeezed or sheared--and usually these forces are happening together--you end up with fragments which are, on average, cubic shapes. It's only if you have a very special stress condition that you get something else. The earth just doesn't do this often."

The researchers also explored fragmentation in two dimensions, or on thin surfaces that function as two-dimensional shapes, with a depth that is significantly smaller than the width and length. There, the fracture patterns are different, though the central concept of splitting polygons and arriving at predictable average shapes still holds.

"It turns out in two dimensions you're about equally likely to get either a rectangle or a hexagon in nature," Jerolmack says. "They're not true hexagons, but they're the statistical equivalent in a geometric sense. You can think of it like paint cracking; a force is acting to pull the paint apart equally from different sides, creating a hexagonal shape when it cracks."

In nature, examples of these two-dimensional fracture patterns can be found in ice sheets, drying mud, or even the earth's crust, the depth of which is far outstripped by its lateral extent, allowing it to function as a de facto two-dimensional material. It was previously known that the earth's crust fractured in this way, but the group's observations support the idea that the fragmentation pattern results from plate tectonics.

Identifying these patterns in rock may help in predicting phenomenon such as rock fall hazards or the likelihood and location of fluid flows, such as oil or water, in rocks.

For the researchers, finding what appears to be a fundamental rule of nature emerging from millennia-old insights has been an intense but satisfying experience.

"There are a lot of sand grains, pebbles, and asteroids out there, and all of them evolve by chipping in a universal manner," says Domokos, who is also co-inventor of the Gömböc, the first known convex shape with the minimal number--just two--of static balance points. Chipping by collisions gradually eliminates balance points, but shapes stop short of becoming a Gömböc; the latter appears as an unattainable end point of this natural process.

The current result shows that the starting point may be a similarly iconic geometric shape: the cube with its 26 balance points. "The fact that pure geometry provides these brackets for a ubiquitous natural process, gives me happiness," he says.

"When you pick up a rock in nature, it's not a perfect cube, but each one is a kind of statistical shadow of a cube," adds Jerolmack. "It calls to mind Plato's allegory of the cave. He posited an idealized form that was essential for understanding the universe, but all we see are distorted shadows of that perfect form."

###

Douglas Jerolmack is a professor in the Department of Earth and Environmental Science in the School of Arts & Sciences and the School of Engineering and Applied Science's Department of Mechanical Engineering and Applied Mechanics at the University of Pennsylvania.

Gábor Domokos is a professor and director of the MTA-BME Morphodynamics Research Group at the Budapest University of Technology and Economics.

Ferenc Kun is a professor in the Department of Theoretical Physics at the University of Debrecen.

János Török is an associate professor in the Department of Theoretical Physics at the Budapest University of Technology and Economics.

Climate scientists increasingly ignore ecological role of indigenous peoples

PENN STATE

 

UNIVERSITY PARK, Pa. -- In their zeal to promote the importance of climate change as an ecological driver, climate scientists increasingly are ignoring the profound role that indigenous peoples played in fire and vegetation dynamics, not only in the eastern United States but worldwide, according to a Penn State researcher.

"In many locations, evidence shows that indigenous peoples actively managed vast areas and were skilled stewards of the land," said Marc Abrams, professor of forest ecology and physiology. "The historical record is clear, showing that for thousands of years indigenous peoples set frequent fires to manage forests to produce more food for themselves and the wildlife that they hunted, and practiced extensive agriculture."

Responding to an article published earlier this year in a top scientific journal that claimed fires set by Native Americans were rare in southern New England and Long Island, New York, and played minor ecological roles, Abrams said there is significant evidence to the contrary.

In an article published today (July 20) in Nature Sustainability, Abrams, who has been studying the historical use of fire in eastern U.S. forests for nearly four decades, refutes those contentions.

"The palaeoecological view -- based on a science of analyzing pollen and charcoal in lake sediments -- that has arisen over the last few decades, contending that anthropogenic fires were rare and mostly climate-driven, contradicts the proud legacy and heritage of land use by indigenous peoples, worldwide," he said.

In his article, Abrams, the Nancy and John Steimer Professor of Agricultural Sciences in the College of Agricultural Sciences, argues that the authors of the previous paper assumed that the scarcity of charcoal indicated that there had not been burning. But frequent, low-intensity fires do not create the amount of charcoal that intense, crown-level, forest-consuming wildfires do, he pointed out.

"Surface fires set by indigenous people in oak and pine forests, which dominate southern New England, often produced insufficient charcoal to be noticed in the sediment," said Abrams. "The authors of the earlier article did not consider charcoal types, which distinguish between crown and surface fires, and charcoal size -- macro versus micro -- to differentiate local versus regional fires."

Also, lightning in New England could not account for the ignition of so many fires, Abrams argues. In southern New England, lightning-strike density is low and normally is associated with rain events.

"The region lacks dry lightning needed to sustain large fires," he said. "Moreover, lightning storms largely are restricted to the summer when humidity is high and vegetation flammability is low, making them an unlikely ignition source."

Early explorers and colonists of southern New England routinely described open, park-like forests and witnessed, firsthand, Native American vegetation management, Abrams writes in his article, adding that oral history and numerous anthropological studies indicate long-term burning and land-use for thousands of years by indigenous people.

Burning near Native American villages and along their extensive trail systems constitutes large land areas, and fires would have kept burning as long as fuel, weather and terrain allowed, he explained. Following European settlement, these open oak and pine woodlands increasingly became closed by trees that previously were held in check by frequent fire.

The authors of the previous paper also argued that fire should not be used as a present-day management tool, a view that Abrams does not support.

The role of anthropogenic fires is front and center in the long-running climate-disturbance debate, according to Abrams, who notes that fires increased with the rise of human populations. The world would be a very different place without those fires, he contends.

"Surprisingly, the importance of indigenous peoples burning in vegetation-fire dynamics is increasingly downplayed among paleoecologists," he writes. "This applies to locations where lightning-caused fires are rare."

Abrams points out that he is not denying the importance of climate in vegetation and fire dynamics or its role in enhancing the extent of human fires. "However," he writes, "in oak-pine forests of southern New England, Native American populations were high enough, lighting-caused fires rare enough, vegetation flammable enough and the benefits of burning and agriculture great enough for us to have confidence in the importance of historic human land management."

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Gregory Nowacki, a scientist in the U.S. Department of Agriculture's Eastern Regional Forest Service Office in Milwaukee, Wisconsin, contributed to the article.

Changes in farming urgent to rescue biodiversity

Over 360 scientists from 42 countries - led by the University of Göttingen and Westlake University China - call for transition of food production systems to agroecological principles

UNIVERSITY OF GÖTTINGEN

 

IMAGE: THE DIVERSITY OF MANY OF OUR EVERYDAY FOODS, SUCH AS THESE CARROTS, HAS BEEN FORGOTTEN, BUT IS AN IMPORTANT BUILDING BLOCK FOR RESILIENT AGRICULTURAL SYSTEMS. view more 

CREDIT: T C WANGER

Over 360 scientists from 42 countries - led by the University of Göttingen and Westlake University China - call for transition of food production systems to agroecological principles.

Humans depend on farming for their very survival but this activity takes up more than one third of the world's landmass and endangers 62% of all threatened species globally. However, agricultural landscapes can support, rather than damage, biodiversity, but only through a global transition to agroecological production. An international team of over 360 scientists from 42 countries, led by the University of Göttingen and Westlake University in China, argue that agroecological principles should be integrated in the post-2020 Global Biodiversity Framework, which aims to reduce threats to biodiversity and will be decided at the 15th Convention of the Parties (COP15) meeting in China. Their Correspondence article was published in Nature Ecology & Evolution.

Reversing the trend in species decline is essential for the benefit of both people and the planet, but it will require coordinated actions and sustainable agriculture. Intensive farming relying on excessive pesticides and fertiliser has negative effects on biodiversity. The authors argue that farming landscapes can provide habitats for biodiversity, promote connectivity between protected areas and increase species' ability to respond to environmental threats. The authors' research agenda includes enhancing global research networks, expanding technical innovation and improving communication. The authors emphasise the importance of working with and supporting farmers, indigenous people and local communities. Diversification in crops together with new varieties and combinations, for instance, can sustain yields. In addition, these actions can support biodiversity and ecosystems whilst providing more nutritious and healthy food for all.

This year is crucial for biodiversity, not just because time is running out to conserve insects and other wildlife, but also because the 15th Convention of the Parties (COP15) will meet in China for the UN Biodiversity Conference, now in 2021 due to COVID-19. At COP15, the post-2020 Global Biodiversity Framework will be agreed which has targets to reduce threats to biodiversity. The authors have elaborated how agroecological principles can help meet each of these targets.

Dr Thomas Cherico Wanger from Westlake University China and University of Göttingen and first author of the correspondence reports, "The importance of agroecology to change agriculture and protect biodiversity has been recognized by many top level organizations, in the scientific community, and by practitioners, which is also reflected in the number and affiliations of signatories of our Correspondence. Following our positive discussions with representatives of the COP15, I hope that this correspondence can help to stimulate discussions in the policy arena and make a real impact on agricultural production systems."

Professor Teja Tscharntke, co-author and Head of the Agroecology Research Group at the University of Göttingen, adds: "Agroecology has the potential to change the way we 'do agriculture'. We hope that our comprehensive research agenda will help to chart the path to sustainable, diversified agriculture and biodiversity conservation in the future."

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Original publication: Wanger et al. Integrating agroecological production in a robust post-2020 global biodiversity framework. Correspondence in Nature Ecology & Evolution (2020). DOI: 10.1038/s41559-020-1262-y

Alternative link - Link - https://www.nature.com/articles/s41559-020-1262-y

If it's big enough and leafy enough the birds will come

Study highlights urban parks and bird diversity

IMAGE: FIG 1. THE NEW YORK CITY METROPOLITAN AREA WITH THE FIVE BOROUGHS OF NYC SHOWN IN LIGHT GRAY. (A) THE 1481 NYC GREEN SPACES CONSIDERED IN THE ANALYSIS AND (B)... view more 

CREDIT: GRAPHIC BY FRANK LA SORTE USING EBIRD DATA AND DATA FROM THE NYC PLANIMETRICS DATABASE THROUGH THE NYC DEPARTMENT OF INFORMATION TECHNOLOGY & TELECOMMUNICATIONS (DOITT). THE DATA WERE CREATED IN MARCH...

CORNELL UNIVERSITY

Ithaca, NY--A new study from the Cornell Lab of Ornithology highlights specific features of urban green spaces that support the greatest diversity of bird species. The findings were published today in the journal Landscape and Urban Planning.

The study focuses specifically on parks in New York City. It uses observations submitted to the eBird citizen-science database from 2002 through 2019 to estimate the variety of species found on an annual and seasonal basis.

Bottom line: the more green space available, the greater the diversity of birds. Models show that Increasing the area of green space by 50% would result in an 11.5% increase in annual and an 8.2% increase in seasonal species diversity.

Trees are also important, particularly for migratory species during spring when models show a 50% increase in canopy cover would result in a 23.3% increase in species diversity.

"Our findings emphasize the broad importance of area and the value of tree canopy cover for spring migrants," said lead author Frank La Sorte at the Cornell Lab. "It also shows that ecological data from citizen scientists can be useful in urban planning and management."

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Argonne's pivotal research discovers practices, technologies key to sustainable farming

DOE/ARGONNE NATIONAL LABORATORY

 

Argonne researchers quantify how to reduce emissions by farms changing their practices and adopting novel technologies.

Currently, the agriculture sector contributes significantly to the greenhouse gas (GHG) emissions in the United States, accounting for nine percent of the nation's overall GHG emissions.  The practices that grain farmers use to produce their crops -- managing fertility, tillage practice and crop rotations -- influence the overall carbon footprint of U.S. agriculture.  By using sustainable practices, farmers could substantially reduce their carbon footprint and become a vital partner to the biofuel industry in its efforts to produce the lowest carbon fuels possible.

"This work is unique since we provide a complete quantification of carbon intensity (CI) for the cradle-to-farm-gate activities by conducting scenario-based analysis for selected farming practices that uses regionalized life cycle inventory data and a spatially explicit soil organic carbon modeling tool." -- Xinyu Liu, postdoctoral appointee

A recent study by researchers in the Energy Systems division at the U.S. Department of Energy's (DOE's) Argonne National Laboratory quantified how much farms might reduce emissions by changing their practices and adopting novel technologies. Xinyu Liu, a postdoctoral appointee, wrote about the pivotal research in Environmental Research Letters, published on July 20. She collaborated with Hoyoung Kwon, principal environmental scientist, and Michael Wang, manager of systems assessments, all of Argonne; and Daniel Northrup, a former contractor to DOE's Advanced Research Projects Agency-Energy (ARPA-E), now with Benson Hill, a crop improvement company in St. Louis.

"This work is unique since we have quantified how the carbon intensity (CI) of corn feedstock would change with a wide range of farming practices and different farming regions. Besides the GHG emissions from manufacturing and applying farming inputs, we have also considered the impacts from soil organic carbon," said Liu.

The research focused on the corn belt of Illinois, Indiana, Iowa, Minnesota, Nebraska, Ohio, Michigan, South Dakota and Wisconsin and showed how different farming practices affect feedstock CI. Sustainable farming professionals could implement lower CI practices, such as adopting conservation tillage, reducing nitrogen fertilizer use, and implementing cover crops, to reduce their carbon footprint, which could improve farm efficiency and help the environment. 

The Argonne team's research has historically focused on the CI of biofuels, which is determined via the life-cycle analysis technique to account for the energy/material uses and emissions as feedstock is produced and converted to fuel. The technique is used by California Air Resources Board's Low Carbon Fuel Standard (LCFS) program to calculate biofuel CI. Farms that reduce biofuel CI can generate LCFS credit, which has monetary value for biofuel producers and potentially for farmers supplying the lower carbon feedstocks. Biofuel producers can improve their overall CI score by rewarding feedstocks with lower CI, thereby further reducing the total CI of biofuels.

Currently, LCFS allows applications from individual biofuel conversion facilities, which resulted in significant investment and innovation in production processes to reduce CI. However, the board scores the CI for feedstocks based on a national average, regardless of the significant field-level variations in CI based on production practice. The Argonne work determines the source of the variation and suggests that a change in farming practice would lead to major emission reductions if implemented broadly.

"We conducted scenario-based CI analysis of corn ethanol, coupled with regionalized inventory data, for various farming practices to manage corn fields and identified key parameters affecting cradle-to-farm-gate GHG emissions," said Liu. "The results demonstrate large spatial variations in CI for corn, and eventually for ethanol, due to farm input uses and land management practices."

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This work shows the importance of different sustainable farming practices to reduce CIs of feedstocks such as corn, which can eventually benefit biofuels.

"Large CI variations in feedstock can result from different farming practices and chemical uses," said Liu. "Therefore, a field-level analysis is needed to better inform farmers to increase crop yields with reduced farming inputs, thus resulting in CI reductions."

This research was supported by ARPA-E.

Argonne National Laboratory seeks solutions to pressing national problems in science and technology. The nation's first national laboratory, Argonne conducts leading-edge basic and applied scientific research in virtually every scientific discipline. Argonne researchers work closely with researchers from hundreds of companies, universities, and federal, state and municipal agencies to help them solve their specific problems, advance America's scientific leadership and prepare the nation for a better future. With employees from more than 60 nations, Argonne is managed by UChicago Argonne, LLC for the U.S. Department of Energy's Office of Science.

The U.S. Department of Energy's Office of Science is the single largest supporter of basic research in the physical sciences in the United States and is working to address some of the most pressing challenges of our time. For more information, visit https://energy.gov/science.

Powerful human-like hands create safer human-robotics interactions

MICHIGAN STATE UNIVERSITY

 

IMAGE: THE NOVEL HUMANOID HAND DESIGN IS A SOFT-HARD HYBRID FLEXIBLE GRIPPER THAT CAN GENERATE LARGER GRASPING FORCE THAN A TRADITIONAL PURE SOFT HAND. view more 

CREDIT: CREDIT: CHANGYONG CAO

EAST LANSING, Mich. - Need a robot with a soft touch? A team of Michigan State University engineers has designed and developed a novel humanoid hand that may be able to help.

In industrial settings, robots often are used for tasks that require repetitive grasping and manipulation of objects. The end of a robot where a human hand would be found is known as an end effector or gripper.

"The novel humanoid hand design is a soft-hard hybrid flexible gripper. It can generate larger grasping force than a traditional pure soft hand, and simultaneously be more stable for accurate manipulation than other counterparts used for heavier objects," said lead author Changyong Cao, director of the Laboratory for Soft Machines and Electronics at MSU and assistant professor in Packaging, Mechanical Engineering, and Electrical and Computer Engineering.

This new research, "Soft Humanoid Hands with Large Grasping Force Enabled by Flexible Hybrid Pneumatic Actuators," is published in Soft Robotics.

Generally, soft-hand grippers -- which are used primarily in settings where an object may be fragile, light and irregularly shaped -- present several disadvantages: sharp surfaces, poor stability in grasping unbalanced loads and relatively weak grasping force for handling heavy loads.

When designing the new model, Cao and his team took into consideration a number of human-environment interactions, from fruit picking to sensitive medical care. They identified that some processes require a safe but firm interaction with fragile objects; most existing gripping systems are not suitable for these purposes.

The team explained that the design novelty resulted in a prototype demonstrating the merits of a responsive, fast, lightweight gripper capable of handling a multitude of tasks that traditionally required different types of gripping systems.

Each finger of the soft humanoid hand is constructed from a flexible hybrid pneumatic actuator -- or FHPA -- driven to bend by pressurized air, creating a modular framework for movement in which each digit moves independently of the others.

"Traditional rigid grippers for industrial applications are generally made of simple but re- liable rigid structures that help in generating large forces, high accuracy and repeatability," Cao said. "The proposed soft humanoid hand has demonstrated excellent adaptability and compatibility in grasping complex-shaped and fragile objects while simultaneously maintaining a high level of stiffness for exerting strong clamping forces to lift heavy loads."

In essence, the best of both worlds, Cao explained.

The FHPA is composed of both hard and soft components, built around a unique structural combination of actuated air bladders and a bone-like spring core.

"They combine the advantages of the deformability, adaptability and compliance of soft grippers while maintaining the large output force originated from the rigidity of the actuator," Cao said.

He believes the prototype can be useful in industries such as fruit picking, automated packaging, medical care, rehabilitation and surgical robotics.

With ample room for future research and development, the team hopes to combine its advances with Cao's recent work on so-called 'smart' grippers, integrating printed sensors in the gripping material. And by combining the hybrid gripper with 'soft arms' models, the researchers aim to more accurately mimic precise human actions.

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The co-authors of the paper include Xiaomin Liu, MSU student Shoue Chen, MSU Foundation Professor Xiaobo Tan from the Department of Electrical and Computer Engineering, and Yunwei Zhao and Dexu Geng from Beihua University.

This research was partially funded by the U.S. Department of Agriculture-National Institute of Food and Agriculture (1016788), MSU Strategic Partnership Grant, National Natural Science Foundation of China (51275004) and an MSU Startup Grant.

(Note for media: Please include a link to the original paper in online coverage: https://doi.org/10.1089/soro.2020.0001)

Michigan State University has been working to advance the common good in uncommon ways for more than 160 years. One of the top research universities in the world, MSU focuses its vast resources on creating solutions to some of the world's most pressing challenges, while providing life-changing opportunities to a diverse and inclusive academic community through more than 200 programs of study in 17 degree-granting colleges.

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Legal marijuana may be slowing reductions in teen marijuana use, study says

UNIVERSITY OF WASHINGTON

 

The legalization of marijuana for Washington state adults may be thwarting a steady downward trend in teen marijuana use, according to new research from the University of Washington.

The longitudinal study of more than 230 teens and young adults finds that teens may be more likely to use marijuana following legalization -- with the proliferation of stores and increasing adult use of the drug -- than they otherwise would have been.

"When we think about marijuana legalization, a worry is that underage use may go up," said Jennifer Bailey, the study's lead author and principal investigator with the Social Development Research Group in the UW School of Social Work. "Early use and heavy use during adolescence can have a lot of negative health consequences, then and later in life, so we don't want teen use to be going up."

Bailey notes that before marijuana legalization, rates of teen marijuana use and other drug use had both been decreasing over the last couple of decades.

The study was published July 9 in the American Journal of Preventive Medicine.

Researchers examined whether marijuana legalization led to teen use of the drug, as well as teens' perceptions that the drug is harmful. Controlling for age, sex, race and parent education of the participants, researchers found that kids who entered their teens more recently were less likely to report they'd used marijuana in the past year. For example, 11% of kids born before 2000 reported using marijuana over the past year at age 15, but only 5% of kids born after 2000 said they used marijuana at age 15.

That finding goes along with the general downward trend in teen substance use. But it was after accounting for this trend that the effect of legalization showed up, Bailey said.

Controlling for the year when kids were born, teens interviewed after voter approval in 2012 of nonmedical marijuana were several times more likely to report they'd used marijuana in the past year. Bailey thinks this means that marijuana legalization may be working against the decreases in teen substance use seen in the recent past.

The new findings differ slightly from other studies showing that rates of underage marijuana use are holding steady or dropping a little after legalization. UW researchers say this may reflect methodology. The UW study was able to account for long-term trends in teen drug use by following kids born between 1989 and 2002 for 15 years and comparing kids who were teenagers before legalization to those who were teenagers after legalization. Other studies have used school-based or optional surveys to assess a larger population at once, and have not always accounted for long-term trends. Those methods supply important information too, Bailey said. They just reflect a different angle on the issue. Broader, point-in-time surveys don't look at individual change.

"They can only see how a whole state changes over time," Bailey said. "Data like ours let you look at individuals and how drug use and behavior change over time, and then we can relate that to changes in policy."

The participants in the UW research are some of the children of participants in a larger and older longitudinal study: the Seattle Social Development Project. That study has followed hundreds of people -- since they were fifth-graders in Seattle elementary schools in the 1980s --to evaluate an assortment of conditions, behaviors and life choices. The results from interviews with 233 of their children, pre- and post-marijuana legalization, were included in this new study.

Child participants ranged in age from 1 to 13 years old when the study began in 2002; marijuana use was assessed from ages 10 to 20. Researchers found that children in the sample entering their teens more recently were more likely to perceive the drug as harmful. For example, 69% of 15-year-olds born before 2000 said regular marijuana use is harmful, but 77% of 15-year-olds born after 2000 said using marijuana regularly is harmful. Bailey attributes this to years of drug prevention and education efforts in schools and communities.

The study did not, however, find an overall association between marijuana legalization and teens' perceived harm from the drug. It could be that changing societal attitudes drive changes in marijuana laws, the authors noted, rather than that changing laws drive perceptions.

Researchers study the perception of harm because people are more likely to engage in a behavior they see as relatively risk-free, Bailey said. In the 1960s and 1970s, for instance, there was a generally low perception of harm from many drugs, and usage was higher than it was in subsequent decades, when perceived harm increased.

"People generally like to take care of themselves. They don't typically do things that carry risk of harm. Throughout the decades that we've been tracking marijuana use, this highly correlates with whether someone will use or not," she said.

The UW study also found no connection between marijuana legalization and teen cigarette smoking; the use of one substance often goes with the other, Bailey said. Teen smoking nationwide has declined precipitously for years, which has been attributed to higher taxes, greater restrictions and widespread public health marketing.

Researchers are watching closely to see whether recent dramatic increases in vaping among teens affect declines in teen smoking rates.

Similar studies in other states where marijuana has been legalized -- the participants in this study lived almost exclusively in Washington state -- could provide further evidence of links between laws and behavior, Bailey said. Currently, nearly a dozen states permit the sale of marijuana for nonmedical use; an additional 22 states allow the drug for medical purposes only.

Nonetheless, the UW findings can help inform prevention messages targeting teens and marijuana, Bailey said.

"A teen usage rate that holds steady isn't good enough if it would normally be going down. We need to devote more attention to prevention of adolescent use in the context of legalization because we want to keep the decreases we've been seeing before legalization was implemented," Bailey said.

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The study was funded by the National Institute on Drug Abuse. Co-authors were Marina Epstein and Rick Kosterman of the UW Social Development Research Group; Sabrina Oesterle, formerly of the Social Development Research Group, now at Arizona State University; Joseph Roscoe of the University of California, Berkeley; and Karl Hill of the University of Colorado Boulder.

For more information, contact Bailey at jabailey@uw.edu.