FSU geologists publish new findings on carbonate melts in Earth's mantle

FLORIDA STATE UNIVERSITY

 

Geologists from Florida State University's Department of Earth, Ocean and Atmospheric Science have discovered how carbon-rich molten rock in the Earth's upper mantle might affect the movement of seismic waves.

The new research was coauthored by EOAS Associate Professor of Geology Mainak Mookherjee and postdoctoral researcher Suraj Bajgain. Findings from the study were published in the journal Proceedings of the National Academy of Sciences .

"This research is quite important since carbon is a crucial constituent for the habitability of the planet, and we are making strides to understand how solid earth may have played a role in storing and influencing the availability of carbon in the Earth's surface," Mookherjee said. "Our research gives us a better understanding of the elasticity, density and compressibility of these rocks and their role in Earth's carbon cycle."

Carbon, one of the primary building blocks for life, is widely distributed throughout the Earth's upper mantle and is mostly stored in forms of carbonate minerals as accessory minerals in mantle rocks. When carbonate-rich magma erupts on the surface, it is notable for its unique, mud-like appearance. These types of eruptions occur at specific locations around the world, such as at the Ol Doinyo Lengai volcano in Tanzania.

Experts believe that the presence of carbonates in rocks significantly lowers the temperature at which they melt. Carbonates that sink to the Earth's interior, via a process known as subduction, likely cause this low-degree melting of the Earth's upper mantle rocks, which plays an important role in the planet's deep carbon cycle.

"Earth's mantle has less free oxygen available at increasing depths," Mookherjee said. "As the mantle upwells through a process of mantle convection, the slowly moving rocks that were reduced, or had less oxygen, at a greater depth become progressively more oxidized at shallower depth. The carbon in the mantle is likely to be reduced deeper in the Earth and get oxidized as the mantle upwells."

This change in depth-dependent oxidation state is likely to cause melting of mantle rocks, a process called redox melting, which could produce carbon-rich molten rock, also known as melts. These melts are likely to affect the physical property of a rock, which can be detected using geophysical probes such as seismic waves, he said.

Prior to this study, geologists had poor knowledge of the elastic properties of these carbonate-induced partial melts, which made them difficult to directly detect.

One set of clues that geologists use to better understand their science are measurements of seismic waves as they move through the layers of the Earth. A type of seismic wave known as a compressional wave is faster than another type known as a shear wave, but at depths of around 180 to 330 kilometers into the Earth, the ratio of their speeds is even higher than is typical.

"This elevated ratio of compressional waves to the shear waves has been a puzzle, and using the findings from our study, we are able to explain this perplexing observation," Mookherjee said.

Minor quantities of carbon-rich melts, approximately 0.05 percent, might be dispersed pervasively through the Earth's deep upper mantle, and that may lead to the elevated ratio of compressional to shear sound velocity, researchers explained.

To conduct the study, researchers took high-pressure ultrasonic measurements and density measurements on cores of the carbonate mineral dolomite. These experiments were complemented by theoretical simulations to provide a new understanding of the fundamental physical properties of carbonate melts.

"We have been trying to understand the elastic and transport properties of aqueous fluids, silicate melt and metallic melt properties, to gain better insight into the mass of volatiles stored in the deep solid earth," Bajgain said.

These findings mean the partially molten rocks in the mantle could hold as much as 80 to 140 parts per million of carbon, which would be 20 to 36 million gigatons of carbon in the deep upper mantle region, making it a substantial carbon reservoir. In comparison, Earth's atmosphere contains just over 410 ppm of carbon, or around 870 gigatons.

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Researchers from Case Western Reserve University in Cleveland, Southern University of Science and Technology in Shenzhen, China, and the University of Chicago contributed to this study. They performed calculations at the High Performance Computing Cluster at Florida State and at supercomputing facilities provided by the National Science Foundation's Extreme Science and Engineering Discovery Environment.

The work was partly supported by the National Science Foundation and the National Natural Science Foundation of China.

Epidemic model shows how COVID-19 could spread through firefighting camps

Demonstrates potential risks, scenarios COVID-19 could pose for fire management

COLORADO STATE UNIVERSITY

 

IMAGE: LARIMER COUNTY AND WELLINGTON FIREFIGHTERS MOP UP A SPOT FIRE AREA ON THE ELK FIRE, OCT. 18, 2019. view more 

CREDIT: BILL COTTON/COLORADO STATE UNIVERSITY PHOTOGRAPHY

With wildfire season in full swing, a COVID-19 outbreak at a traditional large fire camp is a potential disaster. A transient, high-density workforce of firefighters and volunteers responds to blazes while staying in close quarters with limited hygiene - conditions that could facilitate the spread of a contagious respiratory disease.

To support fire agencies as they continue their mission-critical work, a team that includes Colorado State University experts has developed an epidemiological modeling exercise for the USDA Forest Service and other fire managers that demonstrates potential risks and various scenarios COVID-19 could pose for the fire management community. Their model is published in the journal Fire.

The report is co-authored by Jude Bayham, assistant professor in the CSU Department of Agricultural and Resource Economics; and Erin Belval, research scientist in the CSU Department of Forest and Rangeland Stewardship; with first author Matthew P. Thompson, Research Forester at the USDA Forest Service Rocky Mountain Research Station. Bayham and Belval worked with Thompson on the study under a longstanding joint venture agreement with the Forest Service on wildfire-related research, which primarily operates through a partnership with the Warner College of Natural Resources. Thompson serves as the team's liaison to the fire management community.

The researchers developed a simulation model of COVID-19 in the context of a wildfire incident in which the population of firefighters changes over time. The team then analyzed a range of scenarios with different infection transmission rates, percentages of arriving workers who are infected, and fatality rates.

They applied their model to real firefighter population data from three recent wildfires - Highline, Lolo Peak and Tank Hollow - to illustrate potential outbreak dynamics.

During the Highline fire in Idaho, for example, which at its peak had over 1,000 firefighters on site (See Figure 1.), a worst-case scenario would have seen close to 500 infections, and a best-case scenario of eight infections. (See Figure 7.) The researchers used a variety of infection fatality rates to estimate possible deaths due to COVID-19 on the fires, ranging from a low of 0.1% to an "extreme" of 2%, with a medium, or best-guess, of 0.3%. (See Table 1.)

Model is not a prediction

Like most modeling exercises, the report is not intended to predict real numbers; rather, it is a tool for comparing different scenarios and analyzing how various interventions could have small or large effects.

"There is a need in the modeling community to better communicate what we can and cannot learn from models," Bayham said. "The model itself is not meant to be predictive in the sense of number of cases or deaths, because there are so many things moving."

Bayham said the model does provide insight into the relative benefits of two risk-mitigation strategies: screening; and implementing social distancing measures at camps.

They found that aggressive screening as soon as firefighters arrive at camp could reduce the spread of infection, but those benefits diminish as a wildfire incident goes on longer. For longer campaigns lasting several months, aggressive social distancing measures, including increased use of remote briefings, dispersed sleeping camps, and operating under the "module as one" concept, would be more effective at reducing infections than screening. "Module as one" is a social distancing adaptation in which a crew operates mostly as normal but isolates from other, similarly isolating crews.

"It all comes down to exposure, which is a basic risk management concept," Thompson said. "Reducing the exposure of susceptible individuals to those who may be infectious is the idea behind screening and social distancing. Our results underscore the importance of deploying these risk mitigation measures and provide insights into how characteristics of a wildfire incident factor into the effectiveness of these mitigations."

Bayham added, "Both interventions are useful, and they both have an effect, but they each have times and places where they are even more effective,"

Such findings could help inform the wildland fire management community as it develops guidance for fire response strategies during the pandemic.

Thompson added, "I'm fortunate to have worked with Jude and Erin for several years now, and in my opinion their collective depth and breadth of expertise is uniquely well suited to address this complex issue. We're grateful for the support from the Joint Fire Science Program and more broadly the fire management community to continue this important work."

Extending the work

The team will continue their work with a $74,200 award from the Joint Fire Science Program by way of the USDA Forest Service Rocky Mountain Research Station joint venture agreement. They plan to extend their model and create an interactive dashboard for agencies to provide real-time modeling and risk assessment support as fire season continues.

They are also working on a model that would be better suited to analyze season-long implications of COVID-19 outbreaks, spread across multiple fires and geographic distances.

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THIS HAS BEEN THE DREAM SINCE FIRST DISCOVERED IN THE SEVENTIES 

How thoughts could one day control electronic prostheses, wirelessly

Today's brain implants already connect the nervous system to electronic devices to help people with spinal cord injuries regain some motor control. But they use ungainly wires.

STANFORD SCHOOL OF ENGINEERING

 

IMAGE: PHOTO OF A CURRENT NEURAL IMPLANT, THAT USES WIRES TO TRANSMIT INFORMATION AND RECEIVE POWER. NEW RESEARCH SUGGESTS HOW TO ONE DAY CUT THE WIRES. view more 

CREDIT: SERGEY STAVISKY

Stanford researchers have been working for years to advance a technology that could one day help people with paralysis regain use of their limbs, and enable amputees to use their thoughts to control prostheses and interact with computers.

The team has been focusing on improving a brain-computer interface, a device implanted beneath the skull on the surface of a patient's brain. This implant connects the human nervous system to an electronic device that might, for instance, help restore some motor control to a person with a spinal cord injury, or someone with a neurological condition like amyotrophic lateral sclerosis, also called Lou Gehrig's disease.

The current generation of these devices record enormous amounts of neural activity, then transmit these brain signals through wires to a computer. But when researchers have tried to create wireless brain-computer interfaces to do this, it took so much power to transmit the data that the devices would generate too much heat to be safe for the patient.

Now, a team led by electrical engineers and neuroscientists Krishna Shenoy, PhD, and Boris Murmann, PhD, and neurosurgeon and neuroscientist Jaimie Henderson, MD, have shown how it would be possible to create a wireless device, capable of gathering and transmitting accurate neural signals, but using a tenth of the power required by current wire-enabled systems. These wireless devices would look more natural than the wired models and give patients freer range of motion.

Graduate student Nir Even-Chen and postdoctoral fellow Dante Muratore, PhD, describe the team's approach in a Nature Biomedical Engineering paper.

The team's neuroscientists identified the specific neural signals needed to control a prosthetic device, such as a robotic arm or a computer cursor. The team's electrical engineers then designed the circuitry that would enable a future, wireless brain-computer interface to process and transmit these these carefully identified and isolated signals, using less power and thus making it safe to implant the device on the surface of the brain.

To test their idea, the researchers collected neuronal data from three nonhuman primates and one human participant in a (BrainGate) clinical trial.

As the subjects performed movement tasks, such as positioning a cursor on a computer screen, the researchers took measurements. The findings validated their hypothesis that a wireless interface could accurately control an individual's motion by recording a subset of action-specific brain signals, rather than acting like the wired device and collecting brain signals in bulk.

The next step will be to build an implant based on this new approach and proceed through a series of tests toward the ultimate goal.

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Ancient mountains recorded in Antarctic sandstones reveal potential links to global events

UNIVERSITY OF WISCONSIN OSHKOSH

 

IMAGE: A TEAM OF RESEARCHERS LED BY UW OSHKOSH GEOLOGIST TIMOTHY PAULSEN ANALYZED SANDSTONE SAMPLES COLLECTED FROM THE TRANSANTARCTIC MOUNTAINS. view more 

CREDIT: PHOTO COURTESY OF TIMOTHY PAULSEN, UNIVERSITY OF WISCONSIN OSHKOSH

A new analysis of sandstones from Antarctica indicates there may be important links between the generation of mountain belts and major transitions in Earth's atmosphere and oceans.

A team of researchers analyzed the chemistry of tiny zircon grains commonly found in the Earth's continental rock record to determine their ages and chemical compositions. The team included scientists from the University of Wisconsin Oshkosh, Michigan Technological University and ETH Zurich in Switzerland.

The study was published recently in the international peer-reviewed journal Terra Nova, which features short innovative papers about the solid Earth and planetary sciences.

"Mountain building occurs in association with the plate tectonic motions of the continents," said Paulsen, the lead author on the paper. "Geologists have long recognized that the generation of significant mountainous relief has the potential to profoundly influence the chemistry of the Earth's oceans and atmosphere."

Yet there are significant questions about the patterns of mountain building in Earth's past, especially associated with the ancient rock record leading up to the explosion of life about 541 million years ago.

"Mountains tend to be worn down by water and wind that ultimately transports their sedimentary remains to the oceans, leaving an incomplete puzzle for geologists to fit together," said Deering, a coauthor on the paper. "However, there is increasing evidence that missing pieces of the puzzle are found in the sands of ancient beaches and rivers, which are essentially the remnants of mountains produced by weathering and erosion."

The researchers' findings, based on an analysis of a large sample of zircon grains from sandstone recovered in Antarctica, may signify key links in the evolution of the Earth's rock cycle and its atmosphere and oceans.

"We found two primary periods of increased average crustal thickness associated with volcanic chains along convergent plate boundaries, implying an increased proportion of higher mountains at these times," Paulsen said.

"Both episodes occurred during major reorganization of the continents when they separated and drifted on the Earth's surface over time. They also overlap with snowball Earth glaciations--when the whole Earth was frozen over--and associated steps in oxygenation of the atmosphere, which may have been critical for the evolution of life. These correlations suggest an important causal link between plate tectonics and major transitions in Earth's atmosphere and oceans."

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Changes in land evaporation shape the climate

INSTITUTE OF ATMOSPHERIC PHYSICS, CHINESE ACADEMY OF SCIENCES

 

IMAGE: TO PRODUCE BETTER CLIMATIC PREDICTIONS, SCIENTISTS ESTIMATE HOW MUCH WATER IS EVAPORATED FROM THE VEGETATED LAND SURFACE view more 

CREDIT: ÁKOS SZABÓ

Accurate estimation of how much water is evaporated from the vegetated land surface is a challenging task. A physical-based method--such as the complementary relationship (CR) of evaporation, which explicitly accounts for the dynamic feedback mechanisms in the soil-land-atmosphere system and requires minimal data--is advantageous for tracking the ongoing changes in the global hydrological cycle and relating them to historical base values.

Unfortunately, such a method cannot be employed with recently developed remote sensing-based approaches, as they are typically available only for the last couple of decades or so.

An international team of Hungarian, American and Chinese scientists have demonstrated that an existing calibration-free version of the CR method that inherently tracks the aridity changes of the environment in each step of the calculations can better detect long-term trends in continental-scale land evaporation rates than a recently developed and globally calibrated one without such dynamic adjustments to aridity.

With the ongoing climate change, the global hydrological cycle is affected significantly. As climate research indicates, wet areas will get even wetter in general, while dry ones drier, which is not the best scenario for the vast semi-arid and arid regions of the globe. In order to produce better climatic predictions, general circulation models need to upgrade their existing evaporation estimation algorithms. A computational method that automatically adjusts its predictions to short- as well as long-term changes in aridity can improve the existing algorithms employed by these climate models.

"By repeatedly demonstrating the superb capabilities of our calibration-free evaporation method in all venues accessible to us, our ultimate goal is to have the climate modeling community take notice and give it a try," explains Dr Jozsef Szilagyi, the lead author of the study. "As it requires only a few, surface-measured meteorological input variables, such as air temperature, humidity, wind speed and net surface radiation, without detailed information of the soil moisture status or land-surface properties, it can be readily applied with available historical records of meteorological data and see if it indeed improves past predictions of the climate or not."

"Any changes in land use and land cover is inherently accounted for by the CR method via its dynamic aridity term that does not even require precipitation measurements--one of the most variable and difficult meteorological parameter to predict," he concludes.

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The study is published in Advances in Atmospheric Sciences.

This research was supported by the Budapest University of Technology Water Sciences and a Disaster Prevention FIKP grant of EMMI, Hungary.

Maldives records highest level of micro plastic pollution on the planet

Micro plastic pollution in the Maldives, a global tourist destination, is amongst the highest in the world

FLINDERS UNIVERSITY

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VIDEO: FLINDERS UNIVERSITY MALDIVES RESEARCH VIDEO- DR EMILY FOBERT ON LOCATION. view more 

CREDIT: FLINDERS UNIVERSITY https://www.eurekalert.org/multimedia/pub/239420.php

The amount of micro plastic pollution in waters around the Maldives, a global tourist destination known for its beautiful coastline, is amongst the highest in the world and has the potential to severely impact marine life in shallow reefs and threaten the livelihoods of island communities.

Microplastics are pieces of plastic waste that measure less than 5 millimetres long, and due to their often microscopic size are considered invisible water pollutants. Small pieces of plastic can break down over time from plastic bottles, textiles and clothing, remain in the world's oceans.

Marine scientists from Flinders University in Australia recorded the levels of plastic pollution in sand across 22 sites off the coast of Naifaru, the most populous island in Lhaviyani Atoll, to determine how much microplastic is present around the island. Microplastic distribution was found to be ubiquitous in the marine environment, with the results published in Science of the Total Environment journal.

Flinders University Honours student and lead researcher Toby Patti says micro plastics are highly concentrated in waters around Naifaru.

"The concentration of microplastics found on Naifaru in the Maldives (55 -1127.5 microplastics/kg) was greater than those previously found on a highly populated site at Tamil Nadu, India (3 - 611 microplastics/kg), and was a similar concentration to that found on inhabited and uninhabited islands elsewhere in the Maldives (197 -822 particles/kg)."

Microplastic concentration map around Naifaru, an island in the Maldives 141 km north of the capital, Malé. It is the capital and most populous island of Lhaviyani Atoll.

"The majority of micro plastics found in our study were less than 0.4mm in width, so our results raise concerns about the potential for microplastic ingestion by marine organisms in the shallow coral reef system. The accumulation of microplastics is a serious concern for the ecosystem and the local community living off of these marine resources, and can have a negative impact on human health."

The high levels of microplastics could have been transported by ocean currents from neighbouring countries in the Indian Ocean like India, as well as from Maldivian land reclamation policies, poor sewerage & wastewater systems.

Professor Karen Burke Da Silva says notorious 'rubbish islands' used as landfill sites are also contributing to the high concentration of microplastic found around the island.

"Current waste management practices in the Maldives cannot keep up with population growth and the pace of development. The small island nation encounters several challenges regarding waste management systems and has seen a 58% increase of waste generated per capita on local islands in the last decade," says Professor Burke Da Silva.

"Without a significant increase in waste reduction and rapid improvements in waste management, small island communities will continue to generate high levels of microplastic pollution in marine environments, with potential to negatively impact the health of the ecosystem, marine organisms, and local island communities."

The researchers are now looking at the stomach content of coral reef fish to see if they have bellies full of microplastics in a follow up study.

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Disclaimer: AAAS and EurekAlert! are not responsible for the accurac

How to predict a typhoon

Researchers develop model that has the potential to predict tropical cyclones 10 to 30 days in advance

INSTITUTE OF ATMOSPHERIC PHYSICS, CHINESE ACADEMY OF SCIENCES

 

IMAGE: THE WHITE-DOTTED CURVES ARE THE 2018 TYPHOON TRACKS COLLECTED IN THE NORTHWEST PACIFIC OCEAN AS THE BACKGROUND, WHICH IS THE MAJOR TARGET AREA OF THE ASIA-PACIFIC REGIONAL COUPLED PREDICTION SYSTEM... view more 

CREDIT: ADVANCES IN ATMOSPHERIC SCIENCES

Tropical cyclones, also known as typhoons, wreak havoc in Asia and the Pacific. The storms can be deadly -- in 2013, Typhoon Haiyan, the strongest ever recorded, was responsible for 6,340 deaths -- and cost billions in damages. Current forecast models can only predict these storms 10 days in advance, at most, and they cannot precisely predict how intense the storms will become.

To rectify this, an international team of researchers has developed a model that analyzes nearly a quarter of Earth's surface and atmosphere in order to better predict the conditions that birth typhoons, as well as the conditions that lead to more severe storms. They published their results on July 27 in Advances in Atmospheric Sciences.

"The target problem of this study is how to foretell the genesis of typhoons," said paper author Mingkui Li, associate professor in the Key Laboratory of Physical Oceanography in the Ocean University of China and the Pilot National Laboratory for Marine Science and Technology (QNLM). "We specifically address three aspects: the onset time, central pressure and maximum wind speed."

With those three variabilities in mind, the researchers coupled prediction models of the atmosphere and the Earth's surface covering Asia and the Pacific Ocean. They examined three coupled models, each accounting for a different area depth. The researchers also accounted for the influence of one variable on another, such as wind speed on sea surface temperature, a phenomenon known as coupled data assimilation. This influence is well understood and accounted for in climate predictions and in weather forecasts, but it has not been fully applied in understanding how long-term climate affects day-to-day weather and vice versa, according to Li.

"A fine-resolution ocean-atmosphere coupled model that is initialized by downscaled coupled data assimilation is a key for forecasting the typhoon genesis," said Shaoqing Zhang, paper author and professor in the Key Laboratory of Physical Oceanography, QNLM and the International Laboratory for High-Resolution Earth System Model and Prediction (iHESP). "We aimed to provide insights on the time scale that can be used to forecast typhoons in advance, as well as how the resolution of coupled models can affect the prediction of formation, intensity, and track."

From their study, the researchers determined that a high-resolution coupled model with the ability to better understand the relationship between warm sea surface temperatures and weak wind shears -- conditions that favor tropical cyclone formation -- could improve typhoon predictability.

"Although completely addressing these problems, which are important in understanding issues of regional climate and extended-range forecasts, requires plenty of further study, our paper attempts to open the door for it," Zhang said, noting that the team will further improve the physics of the coupled models. "Our goal is to develop a 10 to 30-day extended range prediction system that will ultimately lead to seamless weather-climate predictions."

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This work was supported by the National Key Research & Development Program of China, the National Natural Science Foundation of China and Shandong Province's "Taishan" Scientist Project. This research is also part of a collaborative project between the Ocean University of China, Texas A&M University and the National Center for Atmospheric Research.

Other contributors include Lixin Wu, Xiaopei Lin, Xiaolin Yu, Xiaohui Ma, Weiwei Ma, Haoran Zhao, Kai Mao and Xue Wang, all of whom are affiliated with the Key Laboratory of Physical Oceanography in the Ocean University of China. Qu, Lin, Yu, and X. Ma are also affiliated with QNLM, along with Huiqin Hu, Dongning Jia and Yuhu Chen. Ping Chang and Gohkan Danabasoglu, both with iHESP, also contributed. Chang is also with the Department of Oceanography at Texas A&M University, and Danabasoglu is also with the National Center for Atmospheric Research in Colorado. Other contributors include Xin Liu and Guangliang Liu, both with the National Supercomputing Jinan Center; and Youwei Ma, with the College of Oceanic and Atmospheric Sciences, Ocean University of China.

Dozens of pesticides linked with mammary gland tumors in animal studies

Findings have implications for how federal agencies assess pesticides for breast cancer risk

SILENT SPRING INSTITUTE

 

In an analysis of how regulators review pesticides for their potential to cause cancer, researchers at Silent Spring Institute identified more than two dozen registered pesticides that were linked with mammary gland tumors in animal studies. The new findings raise concerns about how the US Environmental Protection Agency (EPA) approves pesticides for use and the role of certain pesticides in the development of breast cancer.

Several years ago, a resident on Cape Cod in Massachusetts contacted researchers at Silent Spring looking for information on an herbicide called triclopyr. Utility companies were looking to spray the chemical below power lines on the Cape to control vegetation.

"We know pesticides like DDT increase breast cancer risk, so we decided to look into it," says co-author Ruthann Rudel, an environmental toxicologist and director of research at Silent Spring. "After examining pesticide registration documents from EPA, we found two separate studies in which rodents developed mammary gland tumors after being exposed to triclopyr, yet for some reason regulators dismissed the information in their decision not to treat it as a carcinogen."

When manufacturers apply to register a pesticide, EPA reviews existing studies and based on those studies assigns the chemical a cancer classification--for instance, how likely or unlikely the chemical is to cause cancer. After reviewing triclopyr, Silent Spring researchers wondered if evidence of mammary tumors was being ignored for other pesticides as well.

Reporting in the journal Molecular and Cellular Endocrinology, Rudel and Silent Spring scientist Bethsaida Cardona reviewed more than 400 EPA pesticide documents summarizing the health effects of each registered pesticide. They found a total of 28 pesticides linked with mammary gland tumors, yet EPA acknowledged only nine of them as causing mammary tumors and dismissed the evidence entirely for the remaining 19.

Rudel and Cardona also found that many of the pesticides in their analysis behaved like endocrine disruptors, for instance, by interfering with estrogen and progesterone. "Breast cancer is highly influenced by reproductive hormones, which stimulate the proliferation of cells within the breast, making it more susceptible to tumors," says Rudel. "So, it's important that regulators consider this kind of evidence. If they don't, they risk exposing people to pesticides that are breast carcinogens."

Traditionally, toxicologists focus on whether a chemical causes DNA damage when determining its potential to cause cancer. But recent findings in cancer biology show there are many ways chemicals can trigger the development of cancer. For example, chemicals can suppress the immune system, cause chronic inflammation, or disrupt the body's system of hormones, all of which can lead to the growth of breast tumors and other types of tumors as well.

"In light of our findings, we hope EPA updates its guidelines for assessing mammary gland tumors by considering evidence that more completely captures the biology of breast cancer, such as the effects of endocrine disruptors," says Cardona.

Rudel and Cardona recommend that EPA re-evaluate five pesticides in particular--IPBC, triclopyr, malathion, atrazine and propylene oxide--due to their widespread use and the evidence uncovered in the new analysis. IPBC is a preservative in cosmetics; triclopyr is an agricultural herbicide that is also used to control vegetation growth along rights-of-way; malathion is a common residential and agricultural pesticide and is used in some lice treatments; atrazine is one of the most commonly-used herbicides in agriculture; and propylene oxide is used to preserve food, cosmetics, and pharmaceuticals, and has many similarities with ethylene oxide, a known human carcinogen.

The project is part of Silent Spring Institute's Safer Chemicals Program which is developing new cost-effective ways of screening chemicals for their effects on the breast. Knowledge generated by this effort will help government agencies regulate chemicals more effectively and assist companies in developing safer products.

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Funding for this project was provided by the National Institute of Environmental Health Sciences (NIEHS) Breast Cancer and the Environment Research Program (award number U01ES026130), the Cedar Tree Foundation, and Silent Spring Institute's Innovation Fund. The project was also supported by an NIEHS T32 Transdisciplinary Training at the Intersection of Environmental Health and Social Science grant (award number 1T32ES023769-01A1).

Reference:

Cardona, B. and R.A. Rudel. 2020. US EPA's regulatory pesticide evaluations need clearer guidelines for considering mammary gland tumors and other mammary gland effects. Molecular and Cellular Endocrinology. DOI: 10.1016/j.mce.2020.110927

About Silent Spring Institute:

Silent Spring Institute, located in Newton, Mass., is the leading scientific research organization dedicated to uncovering the link between chemicals in our everyday environments and women's health, with a focus on breast cancer prevention. Founded in 1994, the institute is developing innovative tools to accelerate the transition to safer chemicals, while translating its science into policies that protect health. Visit us at http://www.silentspring.org and follow us on Twitter @SilentSpringIns.

Ammonia sparks unexpected, exotic lightning on Jupiter

CORNELL UNIVERSITY

ITHACA, N.Y. - NASA's Juno spacecraft - orbiting and closely observing the planet Jupiter - has unexpectedly discovered lightning in the planet's upper atmosphere, according to a multi-institutional study led by the NASA/Jet Propulsion Laboratory (JPL), which includes two Cornell University researchers.

The work was published Aug. 5 in the journal Nature.

Jupiter's gaseous atmosphere seems placid from a distance, but up close the clouds roil in a turbulent, chemically dynamic realm. As scientists have probed the opaque surface with Juno's sensitive instrumentation, they've learned that Jupiter's lightning occurs not only deep within the water clouds but also in shallow atmospheric regions (at high altitudes with lower pressure) that feature clouds of ammonia mixed with water.

"On the night side of Jupiter, you see fairly frequent flashes - as if you were above an active thunderstorm on Earth," said Jonathan I. Lunine, the David C. Duncan Professor in the Physical Sciences and chair of the Department of Astronomy in the College of Arts and Sciences at Cornell University. "You get these tall columns and anvils of clouds, and the lightning is going continuously. We can get some pretty substantial lightning here on Earth, and the same is true for Jupiter."

The research, "Small Lightning Flashes From Shallow Electrical Storms on Jupiter," was directed by Heidi N. Becker, the Radiation Monitoring Investigation lead of NASA's Juno mission. Lunine and doctoral candidate Youry Aglyamov were the two Cornell co-authors in the study.

Previous missions to Jupiter - such as Voyager 1, Galileo and New Horizons - had all observed lightning. But thanks to Juno's Stellar Reference Unit, a camera designed to detect dim sources of light, the spacecraft's close observational distance and instrument sensitivity enabled lightning detection at a higher resolution than previously possible.

Ammonia is the key. While there is water and other chemical elements such as molecular hydrogen and helium in Jupiter's clouds, ammonia is the "antifreeze" that keeps water in those upper atmospheric clouds from freezing entirely.

Lunine notes Aglyamov's ongoing dissertation work focuses on how lightning is generated under these conditions. The collision of the falling droplets of mixed ammonia and water with suspended water-ice particles constitutes a way to separate charge and produce cloud electrification - resulting in lightning storms in the upper atmosphere.

"The shallow lightning really points to the role of ammonia, and Youry's models are starting to confirm this," Lunine said. "This would be unlike any process that occurs on Earth."

Jupiter's wild gaseous world fascinates Aglyamov.

"Giant planets in general are a fundamentally different kind of world from Earth and other terrestrial planets," he said. "There are hydrogen seas transitioning gradually into skies stacked with cloud decks, weather systems the size of the Earth and who-knows-what in the interior."

The discovery of shallow lightning on Jupiter shifts our understanding of the planet, Aglyamov said.

"Shallow lightning hadn't really been expected and indicates that there's an unexpected process causing it," he said. "It's one more way in which Juno's observations show a much more complex atmosphere of Jupiter than had been predicted. We know enough now to ask the right questions about processes going on there, but as Juno shows, we're in a stage where every answer also tends to multiply the questions."

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Funding for the Cornell portion of this research comes from the Southwest Research Institute.

Implanted neural stem cell grafts show functionality in spinal cord injuries

In mouse studies, the specialized grafts integrated with host networks and behaved much like neurons in a healthy, undamaged spinal cord

UNIVERSITY OF CALIFORNIA - SAN DIEGO

 

IMAGE: COLORIZED SCANNING ELECTRON MICROGRAPH OF A CULTURED HUMAN NEURON. view more 

CREDIT: THOMAS DEERINCK, UC SAN DIEGO NATIONAL CENTER FOR MICROSCOPY AND IMAGING

Using stem cells to restore lost functions due to spinal cord injury (SCI) has long been an ambition of scientists and doctors. Nearly 18,000 people in the United States suffer SCIs each year, with another 294,000 persons living with an SCI, usually involving some degree of permanent paralysis or diminished physical function, such as bladder control or difficulty breathing.

In a new study, published August 5, 2020 in Cell Stem Cell, researchers at University of California San Diego School of Medicine report successfully implanting highly specialized grafts of neural stem cells directly into spinal cord injuries in mice, then documenting how the grafts grew and filled the injury sites, integrating with and mimicking the animals' existing neuronal network.

Until this study, said the study's first author Steven Ceto, a postdoctoral fellow in the lab of Mark H. Tuszynski, MD, PhD, professor of neurosciences and director of the Translational Neuroscience Institute at UC San Diego School of Medicine, neural stem cell grafts being developed in the lab were sort of a black box.

Although previous research, including published work by Tuszynski and colleagues, had shown improved functioning in SCI animal models after neural stem cell grafts, scientists did not know exactly what was happening.

"We knew that damaged host axons grew extensively into (injury sites), and that graft neurons in turn extended large numbers of axons into the spinal cord, but we had no idea what kind of activity was actually occurring inside the graft itself," said Ceto. "We didn't know if host and graft axons were actually making functional connections, or if they just looked like they could be."

Ceto, Tuszynski and colleagues took advantage of recent technological advances that allow researchers to both stimulate and record the activity of genetically and anatomically defined neuron populations with light rather than electricity. This ensured they knew exactly which host and graft neurons were in play, without having to worry about electric currents spreading through tissue and giving potentially misleading results.

They discovered that even in the absence of a specific stimulus, graft neurons fired spontaneously in distinct clusters of neurons with highly correlated activity, much like in the neural networks of the normal spinal cord. When researchers stimulated regenerating axons coming from the animals' brain, they found that some of the same spontaneously active clusters of graft neurons responded robustly, indicating that these networks receive functional synaptic connections from inputs that typically drive movement. Sensory stimuli, such as a light touch and pinch, also activated graft neurons.

"We showed that we could turn on spinal cord neurons below the injury site by stimulating graft axons extending into these areas," said Ceto. "Putting all these results together, it turns out that neural stem cell grafts have a remarkable ability to self-assemble into spinal cord-like neural networks that functionally integrate with the host nervous system. After years of speculation and inference, we showed directly that each of the building blocks of a neuronal relay across spinal cord injury are in fact functional."

Tuszynski said his team is now working on several avenues to enhance the functional connectivity of stem cell grafts, such as organizing the topology of grafts to mimic that of the normal spinal cord with scaffolds and using electrical stimulation to strengthen the synapses between host and graft neurons.

"While the perfect combination of stem cells, stimulation, rehabilitation and other interventions may be years off, patients are living with spinal cord injury right now," Tuszynski said. "Therefore, we are currently working with regulatory authorities to move our stem cell graft approach into clinical trials as soon as possible. If everything goes well, we could have a therapy within the decade."

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Co-authors of the study are Kohel J. Sekiguchi and Axel Nimmerjahn, Salk Institute for Biological Studies and Yoshio Takashima, UC San Diego and Veterans Administration Medical Center, San Diego.