‘Smart Collar’ Could Prevent Tapeworms in Dogs (Medicine)

Dogs infected with echinococcosis play a major role in spreading tapeworms across human populations around the world. Now, researchers have developed a “smart collar” which gradually delivers a steady dose of a deworming drug to dogs. The collar successfully reduces the animals’ risk of echinococcosis, the team reports in PLOS Neglected Tropical Diseases

Dogs can be infected with either Echinococcus granulosus sensu lato, which causes cystic echinococcosis (CE), or E. multilocularis, which causes alveolar echinococcosis (AE). In China, a national survey showed that CE is endemic in at least 368 counties in northwest China and is co-endemic with AE in 115 of those counties. The role of dogs in transmitting echinococcosis in these areas is significant, and efforts to dose dogs with monthly deworming treatments have been difficult to implement.

In the new work, Xiao-Nong Zhou of the Chinese Center for Disease Control and Prevention and colleagues developed a deworming collar which delivers praziquantel (PZQ), known to be the most effective deworming drug. They designed the collar to be waterproof, anti-collision, cold-proof, and to automatically deliver a regular, quantitative dose of PZQ. 18 smart deworming collars were used for field testing in Seni district of China, and 523 collars were tested in Henzuo city. Dogs for the trial were randomly selected from all registered dogs in each jurisdiction.

In pre-field trials, the 551 collars were 100.0% anti-collision, 99.5% waterproof and 100.0% coldproof, and the automatic PZQ delivery occurred 87.8% of the time, even with the collars being attached to dogs for 12 months in the harsh climates of remote locations on the Tibetan Plateau. The compliance rate of dog owners to attach the collar to their dog was 94.7% in Seni district and 88.8% in Hezuo city. When compared to a control group, dogs in Seni district wearing the smart collar had a 0.182 times risk of a positive Echinococcus antigen test (95%CI 0.049-0.684, P=0.012) and dogs in Hezuo had a 0.336 times risk of a positive antigen test (95% CI 0.178-0.706, P=0.003).

“In order to prevent the transmission of echinococcosis from dogs to humans and livestock completely, we developed a smart Internet of Things (IoT)-based deworming collar which can deliver PZQ baits for dogs automatically and regularly,” the researchers say. “Two pilot studies have showed that it is an excellent alternative to existing manual deworming methods, and the difficulties associated with performing deworming in remote areas with scarce resources can be overcome.”

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Peer-reviewed; Experimental study; Animals

In your coverage please use this URL to provide access to the freely available article in PLOS Neglected Tropical Diseases:

http://journals.plos.org/plosntds/article?id=10.1371/journal.pntd.0009443

Funding: SJY was continuously supported by the Ganzi Prefecture Workgroup Projects for Echinococcosis Prevention and Control (the serial numbers are 2016-07, 2017-06, 2018-02 and 2019-02 respectively), which was initiated by China CDC to advance the echinococcosis control program in 2015 in the Qinghai-Tibet Plateau. JZL received the award from the NHC Key Laboratory of Echinococcosis Prevention and Control Project (Supported by the Non-profit Central Research Institute Fund of Chinese Academy of Medical Sciences, 2019PT320004), and JYM received the Key R & D Transformation Projects (Supported by Science and Technology Committee of Qinghai Province, 2020-SF-133). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Featured image: Development and field tests of smart deworming collar (A: 3D stacked graph of smart collar; B: Embedded modules for smart collar; C: Overall shape of Smart collar; D: Recovery of collars in July 2019 in Seni district after they had been attached for a year). © Yang S-J et al., 2021, PLOS Neglected Tropical Diseases, CC-BY 4.0 (https://creativecommons.org/licenses/by/4.0/)


Reference: Yang S-J, Xiao N, Li J-Z, Feng Y, Ma J-Y, Quzhen G-S, et al. (2021) Smart deworming collar: A novel tool for reducing Echinococcus infection in dogs. PLoS Negl Trop Dis 15(7): e0009443. https://doi.org/10.1371/journal.pntd.0009443


Provided by PLOS

Our Genes Shape Our Gut Bacteria (Biology)

Our gut microbiome — the ever-changing “rainforest” of bacteria living in our intestines — is primarily affected by our lifestyle, including what we eat or the medications we take, most studies show.

But a University of Notre Dame study has found a much greater genetic component at play than was once known.

In the study, published recently in Science, researchers discovered that most bacteria in the gut microbiome are heritable after looking at more than 16,000 gut microbiome profiles collected over 14 years from a long-studied population of baboons in Kenya’s Amboseli National Park. However, this heritability changes over time, across seasons and with age. The team also found that several of the microbiome traits heritable in baboons are also heritable in humans.

“The environment plays a bigger role in shaping the microbiome than your genes, but what this study does is move us away from the idea that genes play very little role in the microbiome to the idea that genes play a pervasive, if small, role,” said Elizabeth Archie, professor in the Department of Biological Sciences and a principal investigator on the study who is also affiliated with the Eck Institute for Global Health and the Environmental Change Initiative.

The gut microbiome performs several jobs. In addition to helping with food digestion, it creates essential vitamins and assists with training the immune system. This new research is the first to show a definitive connection with heritability.

Previous studies on the gut microbiome in humans showed only 5 to 13 percent of microbes were heritable, but Archie and the research team hypothesized the low number resulted from a “snapshot” approach to studying the gut microbiome: All prior studies only measured microbiomes at one point in time. 

In their study, the researchers used fecal samples from 585 wild Amboseli baboons, typically with more than 20 samples per animal. Microbiome profiles from the samples showed variations in the baboons’ diets between wet and dry seasons. Collected samples included detailed information about the host, including known descendants, data on environmental conditions, social behavior, demography and group-level diet at the time of collection.

The research team found that 97 percent of microbiome traits, including overall diversity and the abundance of individual microbes, were significantly heritable. However, the percentage of heritability appears much lower — down to only 5 percent — when samples are tested from only a single point in time, as is done in humans. This emphasizes the significance of studying samples from the same host over time.

“This really suggests that in human work, part of the reason researchers haven’t found that heritability is because in humans they don’t have a decade and half of fecal samples in the freezer, and they don’t have all the initial host (individual) information they need to tease these details out,” said Archie.

The team did find evidence that environmental factors influence trait heritability in the gut microbiome. Microbiome heritability was typically 48 percent higher in the dry season than in the wet, which may be explained by the baboons’ more diverse diet during the rainy season. Heritability also increased with age, according to the study.

Because the research also showed the significant impact of environment on the gut microbiomes in baboons, their findings agreed with previous studies showing that environmental effects on the variation in the gut microbiome play a larger role than additive genetic effects. Combined with their discovery of the genetic component, the team plans to refine its understanding of the environmental factors involved.

But knowing that genes in the gut microbiome are heritable opens the door to identifying microbes in the future that are shaped by genetics. In the future, therapies could be tailored for people based on the genetic makeup of their gut microbiome.

The Amboseli Baboon Project, started in 1971, is one of the longest-running studies of wild primates in the world. Focused on the savannah baboon, the project is located in the Amboseli ecosystem of East Africa, north of Mount Kilimanjaro. Research teams have tracked hundreds of baboons in several social groups over the course of their entire lives. Researchers currently monitor around 300 animals, but have accumulated life history information on more than 1,500 animals.

The research was funded by the National Science Foundation.

In addition to Archie and former postdoctoral student Laura Grieneisen, other authors include fellow principal investigators Ran Blekhman of the University of Minnesota and Jenny Tung of Duke University and the Canadian Institute for Advanced Research; Mauna Dasari, Johannes Björk and David Jansen of the University of Notre Dame; Trevor Gould of the University of Minnesota; Jean-Christophe Grenier, Vania Yotova and Luis B. Barreiro of Centre Hospitalier Universitaire Sainte-Justine Research Center; Neil Gottel and Jack Gilbert of the University of California, San Diego; Jacob B. Gordon, Laurence R. Gesquiere and Susan C. Alberts of Duke University; Niki H. Learn of Princeton University; and Tim L. Wango, Raphael S. Mututua, Kinyua Warutere and Long’ida Siodi of the Amboseli Research Project.

The study, “Gut microbiome heritability is nearly universal but environmentally contingent”, Science  09 Jul 2021: Vol. 373, Issue 6551, pp. 181-186 DOI: 10.1126/science.aba5483

Featured image: Baboons playing © Notre Dame


Provided by Notre Dame

Pressure-induced High-temperature Superconductivity Retained Without Pressure in FeSe Single Crystals (Physics)

Development of a New Pressure-Quench Technique Demonstrates Superconductivity in Iron Selenide Crystals Sans Pressure

In a critical next step toward room-temperature superconductivity at ambient pressure, Paul Chu, Founding Director and Chief Scientist at the Texas Center for Superconductivity at the University of Houston (TcSUH),  Liangzi Deng, research assistant professor of physics at TcSUH, and their colleagues at TcSUH conceived and developed a pressure-quench (PQ) technique that retains the pressure-enhanced and/or -induced high transition temperature (Tc) phase even after the removal of the applied pressure that generates this phase.

Pengcheng Dai, professor of physics and astronomy at Rice University and his group, and Yanming Ma, Dean of the College of Physics at Jilin University, and his group contributed toward successfully demonstrating the possibility of the pressure-quench technique in a model high temperature superconductor, iron selenide (FeSe). The results were published in the journal  Proceedings of the National Academy of Science USA­­­.

“We derived the pressure-quench method from the formation of the man-made diamond by Francis Bundy from graphite in 1955 and other metastable compounds,” said Chu. “Graphite turns into a diamond when subjected to high pressure at high temperatures. Subsequent rapid pressure quench, or removal of pressure, leaves the diamond phase intact without pressure.”

Chu and his team applied this same concept to a superconducting material with promising results.

“Iron selenide is considered a simple high-temperature superconductor with a transition temperature (Tc) for transitioning to a superconductive state at 9 Kelvin (K) at ambient pressure,” said Chu.

“When we applied pressure, the Tc increased to ~ 40 K, more than quadrupling that at ambient, enabling us to unambiguously distinguish the superconducting PQ phase from the original un-PQ phase. We then tried to retain the high-pressure enhanced superconducting phase after removing pressure using the PQ method, and it turns out we can.”

Paul Chu (right) is Founding Director and Chief Scientist at the Texas Center for Superconductivity at the University of Houston (TcSUH). Liangzi Deng (left) is research assistant professor of physics at TcSUH. ©University of Houston

Dr. Chu and colleagues’ achievement brings scientists a step closer to realizing the dream of room-temperature superconductivity at ambient pressure, recently reported in hydrides only under extremely high pressure.

Superconductivity is a phenomenon discovered in 1911 by Heike Kamerlingh Onnes by cooling mercury below its transition Tof 4.2 K, attainable with the aid of liquid helium, which is rare and expensive. The phenomenon is profound because of superconductor’s ability to exhibit zero resistance when electricity moves through a superconducting wire and its expulsion of magnetic field generated by a magnet. Subsequently, its vast potential in the energy and transportation sectors was immediately recognized.

To operate a superconducting device, one needs to cool it to below its Tc, which requires energy. The higher the Tc, the less energy needed. Therefore, raising the Tc with the ultimate goal of room temperature of 300 K has been the driving force for scientists in superconductivity research since its discovery.

In defiance of the then-prevailing belief that Tc could not exceed the 30’s K, Paul Chu , and colleagues discovered superconductivity in a new family of compounds at 93 K in 1987, achievable by the mere use of the inexpensive, cost-effective industrial coolant of liquid nitrogen. The Thas continuously been raised since to 164 K by Chu et al. and other subsequent groups of scientistsRecently a T of 287 K was achieved by Dias et al. of Rochester University in carbon-hydrogen-sulfide under 267 gigapascal (GPa).

A maglev train, short for “magnetic levitation,” was first built in Shanghai in 2004 and utilizes the science of superconductivity. It reaches top speeds at 375 miles per hour. © University of Houston

In short, the advancement of Tc to room temperature is indeed within reach. But for future scientific and technological development of hydrides, characterization of materials and fabrication of devices at ambient pressures is necessary.

“Our method allows us to make the material superconducting with higher Tc without pressure. It even allows us to retain at ambient the non-superconducting phase that exists only in FeSe above 8 GPa. There is no reason that the technique cannot be equally applied to the hydrides that have shown signs of superconductivity with a Tc approaching room temperature.”

The achievement inches the academic community closer toward room-temperature superconductivity (RTS) without pressure, which would mean ubiquitous practical applications for superconductors from the medical field, through power transmission and storage to transportation, with impacts whenever electricity is used. 

Superconductivity as a means to improve power generation, storage and transmission is not a new idea, but it requires further research and development to become widespread before room temperature superconductivity becomes a reality. The capacity for zero electrical resistance means energy can be generated, transmitted and stored with no loss – an enormous low-cost advantage. However, current technology demands that the superconducting device be kept at severely low temperatures to retain its unique state, which still requires additional energy as an overhead cost, not to mention the potential hazard of the accidental failure of the cooling system. Hence, an RTS superconductor with no extra pressure to sustain its beneficial properties is a necessity to move forward with more practical applications.

The properties of superconductivity are also paving the way for a competitor to the famous bullet train seen throughout East Asia: a maglev train. Short for “magnetic levitation,” the first maglev train built in Shanghai in 2004 successfully broadened usage in Japan and South Korea and is under consideration for commercial operation in the US. At top speeds of 375 miles per hour, cross country flights see a quick competitor in the maglev train. A room temperature superconductor could help Elon Musk realize his dream of a “hyperloop” to travel at a speed of 1000 miles per hour.

This successful implementation of the PQ technique on room temperature superconductors discussed in Chu and Deng’s paper is critical in making superconductors possible for ubiquitous practical applications.

Now the riddle of RTS at ambient pressure is even closer to being solved.

Featured image: A superconductor possesses the unique ability to exhibit zero resistance when electricity moves through a superconducting wire and expulsion of a magnetic field generated by a magnet – appearing to the eye as levitation. © University of Houston


Reference: Liangzi Deng, Trevor Bontke, Rabin Dahal, Yu Xie, Bin Gao, Xue Li, Ketao Yin, Melissa Gooch, Donald Rolston, Tong Chen, Zheng Wu, Yanming Ma, Pengcheng Dai, Ching-Wu Chu, “Pressure-induced high-temperature superconductivity retained without pressure in FeSe single crystals”, PNAS July 13, 2021 118 (28) e2108938118; https://doi.org/10.1073/pnas.2108938118


Provided by University of Houston

How Unconventional Superconductors Carry Electric Current With No Loss At High Temperatures (Physics)

Nickelate materials give scientists an exciting new window into how unconventional superconductors carry electric current with no loss at relatively high temperatures.BY GLENNDA CHUI

Ever since the 1986 discovery that copper oxide materials, or cuprates, could carry electrical current with no loss at unexpectedly high temperatures, scientists have been looking for other unconventional superconductors that could operate even closer to room temperature. This would allow for a host of everyday applications that could transform society by making energy transmission more efficient, for instance.

Nickel oxides, or nickelates, seemed like a promising candidate. They’re based on nickel, which sits next to copper on the periodic table, and the two elements have some common characteristics. It was not unreasonable to think that superconductivity would be one of them.

But it took years of trying before scientists at the Department of Energy’s SLAC National Accelerator Laboratory and Stanford University finally created the first nickelate that showed clear signs of superconductivity.

Now SLAC, Stanford and Diamond Light Source researchers have made the first measurements of magnetic excitations that spread through the new material like ripples in a pond. The results reveal both important similarities and subtle differences between nickelates and cuprates. The scientists published their results in Science today.

“This is exciting, because it gives us a new angle for exploring how unconventional superconductors work, which is still an open question after 30-plus years of research,” said Haiyu Lu, a Stanford graduate student who did the bulk of the research with Stanford postdoctoral researcher Matteo Rossi and SLAC staff scientist Wei-Sheng Lee.

“Among other things,” he said, “we want to understand the nature of the relationship between cuprates and nickelates: Are they just neighbors, waving hello and going about their separate ways, or more like cousins who share family traits and ways of doing things?”

The results of this study, he said, add to a growing body of evidence that their relationship is a close one.

superconductor_artwork_sv_final.jpg

A new study found that nickelate superconductors, like their cousins the cuprates, are antiferromagnetic. Their electron spins – represented by gold arrows here – form a checkerboard pattern, so each down spin is surrounded by up spins and vice versa. The alternating spins cancel each other out, so the material as a whole is not magnetic in the ordinary sense. Researchers at SLAC, Stanford and Diamond Light Source discovered important similarities like this one as well as subtle differences between the two materials. (Greg Stewart/SLAC National Accelerator Laboratory)

Spins in a checkerboard

Cuprates and nickelates have similar structures, with their atoms arranged in a rigid lattice.  Both come in thin, two-dimensional sheets that are layered with other elements, such as rare-earth ions. These thin sheets become superconducting when they’re cooled below a certain temperature and the density of their free-flowing electrons is adjusted in a process known as doping.

The first superconducting nickelate was discovered in 2019 at SLAC and Stanford. Last year, the same SLAC/Stanford team that performed this latest experiment published the first detailed study of the nickelate’s electronic behavior. That study established that in undoped nickelate, electrons flow freely in nickel oxide layers, but electrons from the intervening layers also contribute electrons to the flow. This creates a 3D metallic state that’s quite different from what is seen in cuprates, which are insulators when undoped.

Magnetism is also important in superconductivity. It’s created by the spins of a material’s electrons. When they’re all oriented in the same direction, either up or down, the material is magnetic in the sense that it could stick to the door of your fridge.

Cuprates, on the other hand, are antiferromagnetic: Their electron spins form a checkerboard pattern, so each down spin is surrounded by up spins and vice versa. The alternating spins cancel each other out, so the material as a whole is not magnetic in the ordinary sense.

Would nickelate have those same characteristics? To find out, researchers took samples of it to the Diamond Light Source synchrotron in the UK for examination with resonant inelastic X-ray scattering, or RIXS. In this technique, scientists scatter X-ray light off a sample of material. This injection of energy creates magnetic excitations – ripples that travel through the material and randomly flip the spins of some of its electrons. RIXS allows scientists to measure very weak excitations that couldn’t be observed otherwise.

mottness_superconductivity_characters_friends_sv_final.jpg

Illustration showing two superconducting materials, nickelate and cuprate, as cartoon characters with blocky heads holding hands, evidence of their close relationship.
The first measurements of magnetic excitations rippling through a nickelate (Ni) superconductor show it’s closely related to cuprate (Cu) superconductors, which conduct electricity with no loss at relatively warm temperatures. The study by researchers at SLAC, Stanford and Diamond Light Source revealed important similarities and subtle differences between the two materials. (Greg Stewart/SLAC National Accelerator Laboratory)

Creating new recipes

“What we find is quite interesting,” Lee said. “The data show that nickelate has the same type of antiferromagnetic interaction that cuprates have. It also has a similar magnetic energy, which reflects the strength of the interactions between neighboring spins that keep this magnetic order in place. This implies that the same type of physics is important in both.”

But there are also differences, Rossi noted. Magnetic excitations don’t spread as far in nickelates, and die out more quickly. Doping also affects the two materials differently; the positively charged “holes” it creates are concentrated around nickel atoms in nickelates and around oxygen atoms in cuprates, and this affects how their electrons behave.

As this work continues, Rossi said, the team will test how doping the nickelate in various ways and swapping different rare earth elements into the layers between the nickel oxide sheets affect the material’s superconductivity ­– paving the way, they hope, to discovery of better superconductors.

Lu, Rossi, Lee and six other members of the research team are investigators with the Stanford Institute for Materials and Energy Sciences (SIMES) at SLAC, which received major funding from the DOE Office of Science. Researchers from the Lorentz Institute for Theoretical Physics at Leiden University in the Netherlands also contributed to this work.

Citation: Haiyu Lu et al., Science, 9 July 2021 (10.1126/science.abd7726)

Featured image: Illustration showing nickelate and cuprate superconductors as cartoon characters that are either close friends holding hands or neighbors talking over a fence © Greg Stewart/SLAC National Accelerator Laboratory


Provided by SLAC

Longest Known Continuous Record of the Paleozoic Discovered in Yukon Wilderness (Geology)

Stanford-led expeditions to a remote area of Yukon, Canada, have uncovered a 120-million-year-long geological record of a time when land plants and complex animals first evolved and ocean oxygen levels began to approach those in the modern world.

Hundreds of millions of years ago, in the middle of what would eventually become Canada’s Yukon Territory, an ocean swirled with armored trilobites, clam-like brachiopods and soft, squishy creatures akin to slugs and squid.

A trove of fossils and rock layers formed on that ancient ocean floor have now been unearthed by an international team of scientists along the banks of the Peel River a few hundred miles south of the Arctic’s Beaufort Sea. The discovery reveals oxygen changes at the seafloor across nearly 120 million years of the early Paleozoic era, a time that fostered the most rapid development and diversification of complex, multi-cellular life in Earth’s history.

“It’s unheard of to have that much of Earth’s history in one place,” said Stanford University geological scientist Erik Sperling, lead author of a July 7 study detailing the team’s findings in Science Advances. Most rock formations from the Paleozoic Era have been broken up by tectonic forces or eroded over time. “There’s nowhere else in the world that I know of where you can study that long a record of Earth history, where there’s basically no change in things like water depth or basin type.”

Oxygen was scarce in the deep water of this and other oceans at the dawn of the Paleozoic, roughly 541 million years ago. It stayed scarce until the Devonian, roughly 405 million years ago, when, in a geological blink – no more than a few million years – oxygen likely rocketed to levels close to those in modern oceans and the diversity of life on Earth exploded. Big, predatory fish appeared. Primitive ferns and conifers marched across continents previously ruled by bacteria and algae. Dragonflies took flight. And all of this after nearly four billion years of Earth’s landscapes being virtually barren.

Scientists have long debated what might have caused the dramatic shift from a low oxygen world to a more oxygenated one that could support a diverse web of animal life. But until now, it has been difficult to pin down the timing of global oxygenation or the long-term, background state of the world’s oceans and atmosphere during the era that witnessed both the so-called Cambrian explosion of life and the first of Earth’s “Big Five” mass extinctions, about 445 million years ago at the end of the Ordovician.

“In order to make comparisons throughout these huge swaths of our history and understand long-term trends, you need a continuous record,” said Sperling, an assistant professor of geological sciences at Stanford’s School of Earth, Energy & Environmental Sciences (Stanford Earth).

Context for past life

With permission from the Na Cho Nyak Dun and Tetlit Gwitch’in communities in Yukon, Sperling’s team, which included researchers from Dartmouth College and the Yukon Geological Survey, spent three summers at the Peel River site. Arriving by helicopter, the research team hacked through brush with machetes beside Class VI rapids to collect hundreds of fist-sized samples of rock from more than a mile of interbedded layers of shale, chert and lime mudstone.

Back at Sperling’s lab at Stanford, a small army of summer undergraduates and graduate students worked over five summers to help analyze the fossils and chemicals entombed in the rocks. “We spent a lot of time splitting open rocks and looking at graptolite fossils,” Sperling said. Because graptolites evolved a vast array of recognizable body shapes relatively quickly, the pencil-like markings left by the fossils of these colony-dwelling sea creatures give geologists a way to date the rocks in which they’re found.

Once the researchers had finished identifying and dating graptolite fossils, they ground the rocks in a mill, then measured iron, carbon, phosphorous and other elements in the resulting powder to assess the ocean conditions at the time and place where the layers formed. They analyzed 837 new samples from the Peel River site, as well as 106 new samples from other parts of Canada and 178 samples from around the world for comparison.

Winners and losers

The data show low oxygen levels, or anoxia, likely persisted in the world’s oceans for millions of years longer than previously thought – well into the Phanerozoic, when land plants and early animals began to diversify. “The early animals were still living in a low oxygen world,” Sperling said. Contrary to long-held assumptions, the scientists found Paleozoic oceans were also surprisingly free of hydrogen sulfide, a respiratory toxin often found in the anoxic regions of modern oceans.

When oxygen eventually did tick upward in marine environments, it came about just as larger, more complex plant life took off. “There’s a ton of debate about how plants impacted the Earth system,” Sperling said. “Our results are consistent with a hypothesis that as plants evolved and covered the Earth, they increased nutrients to the ocean, driving oxygenation.” In this hypothesis, the influx of nutrients to the sea would have given a boost to primary productivity, a measure of how quickly plants and algae take carbon dioxide and sunlight, turn them into new biomass – and release oxygen in the process.

The change probably killed off graptolites. “Although more oxygen is really good for a lot of organisms, graptolites lost the low oxygen habitat that was their refuge,” Sperling said. “Any environmental change is going to have winners and losers. Graptolites might have been the losers.”

Co-author Richard Stockey is a PhD student, Tessa Brunoir is a research assistant and Una Farrell is an affiliate in the department of geological sciences at Stanford. Liam Bhajan ’17 majored in geological sciences as an undergraduate. Additional co-authors are affiliated with St. Francis Xavier University; Yukon Geological Survey; Trinity College, Dublin; Georgia Institute of Technology; Virginia Polytechnic University and State University; Western University Canada; University of Portsmouth; Dartmouth College; University of Puerto Rico, Mayagüez; Vanderbilt University; and Yale University.

This work was supported by an Ocean Sciences Research Fellowship from the Alfred P. Sloan Foundation, the affiliates of the Stanford Program on Deep-water Depositional Systems, the McGee-Levorsen fund at Stanford, the National Science Foundation, the Agouron Institute and the Natural Sciences and Engineering Research Council (Canada).

Featured image: Ordovician black shales of the Mount Hare Formation, Road River Group (approximately 465 million years old) rise above conglomerates of the Aberdeen Member. The dangerous rapids of Aberdeen Canyon (Nan Zhak Nadhàdlaii), created by the Peel River cutting through the resistant conglomerates, appear at bottom left. (Image credit: Erik Sperling)


Reference: Erik A. Sperling, Michael J. Melchin et al., “A long-term record of early to mid-Paleozoic marine redox change”, Science Advances  07 Jul 2021: Vol. 7, no. 28, eabf4382 DOI: 10.1126/sciadv.abf4382


Provided by Stanford University