Earth

Native forests make up 1percent of the landscape in South Africa but could play a key role in reducing atmospheric carbon and identifying sustainable development practices that can be used globally to counter climate change, according to a Penn State researcher.

"As we think about pathways for reducing atmospheric carbon dioxide concentrations, one of the available approaches is to use the natural world as a sponge," said Erica Smithwick, professor of geography and director of the Center for Landscape Dynamics at Penn State.

The challenge, according to Smithwick, is to use forests to store carbon while also meeting local community needs. As trees grow, they absorb and store carbon through photosynthesis. Carbon makes up about half of a tree's mass, but amounts vary by species. To find its carbon stock, scientists use equations based on the tree's diameter and other variables, like height and wood density, rather than cutting down and weighing each species.

In 2011, Smithwick tagged and measured trees in the Dwesa-Cwebe nature reserve in the Eastern Cape Province with help from students in Penn State's Parks and People study abroad program. She remeasured the trees five years later while in South Africa on a Core Fulbright U.S. Scholarship and analyzed the forests' carbon content. The results of the study, one of the first to quantify carbon content in Africa, appear in a recent issue of the journal Carbon Management.

Smithwick found that the coastal, indigenous forests store a moderate to large amount of carbon. They are also a biodiversity hotspot and thus important for conservation. The local communities depend on the forests for resources such as medicinal plants, fuelwood and timber, as well as their spiritual needs, Smithwick added.

"As we move toward the sustainable development of these places, we need to think about how the local communities are able to value and work with these characteristics of the forests," said Smithwick, who also holds an appointment in Penn State's Earth and Environmental Systems Institute. "Understanding what is an optimal level of productivity extraction from the natural system so we're not degrading the system is an area of interest. We're trying to figure out what the balance between forest productivity and resource extraction is."

Smithwick noted that the large amount of forest productivity, or how quickly the forests grow, and small amount of human use of forest resources suggest that humans are not negatively influencing the Dwesa-Cwebe forests. She added that access to the nature reserve is limited, and other reserves see more resource extraction.

The South African government manages Dwesa-Cwebe but plans eventually to hand over management of the park to the surrounding local communities. Smithwick said that conservation of the area must integrate human interactions and values into a development model that recognizes how humans can benefit a forest system if managed in a sustainable way.

"We have to recognize the importance of these natural forests and their biodiversity and carbon values, but we also have to situate that in a sustainable development challenge," said Smithwick, who is also director of the Huck Institutes of Life Sciences Ecology Institute and associate director of the Institutes of Energy and the Environment. "The forest in South Africa is a good case study for how we start to think about balancing these considerations. The lessons learned from this hopefully can resonate to how we think about these challenges in other parts of the world."

In nutrient-poor deep-sea sediments, microbes belonging to the Archaea have outcompeted bacterial microorganisms for millions of years. Their ability to efficiently scavenge dead cells makes them the basal producers in the food chain.

Archaea constitute a group of unicellular microorganisms that are primarily known as highly versatile denizens of extremely demanding habitats. Viewed with the light microscope, they look very much like bacteria, but the two groups differ markedly from each other in many respects. In particular, there are important differences between them with respect to their metabolic capabilities, and these largely determine which ecological niches they can exploit. Researchers led by Professor William Orsi of the Department of Earth and Environmental Sciences at Ludwig-Maximilians-Universitaet (LMU) in Munich, in cooperation with American colleagues belonging to the Deep Life Community [which is part of the Deep Carbon Observatory (DCO)] have now discovered that species of Archaea have not only managed to survive for many millions of years in sediments far below the floor of the open ocean, but that they cope with the difficult living conditions in the subseafloor biosphere far better than bacteria do. The new findings suggest that these adaptable Archaea are likely to play an important role in the geochemical carbon and nitrogen cycles in this enormous ecosystem. The study appears in the online journal Science Advances.

Sediments deposited in the oceans near continental margins often exhibit low levels of oxygen, because large amounts of organic carbon are constantly being exported to the seafloor. The organic carbon is rapidly metabolized by microorganisms, and this process consumes all the available oxygen. In the open ocean, however, the main source of organic nutrients in the seafloor is made up of dead organisms that inexorably sink to the seafloor. This in turn means that far less organic carbon is available for metabolism, and consequently the oxygen in the sediments below the seafloor is preserved. "Modelling studies suggest that between 10 and 40% of these sediments, from the seafloor down into the underlying crust, are supplied with oxygen," says Orsi. "This is a huge region, whose biosphere is as yet largely unexplored."

In order to learn more about this habitat, which is difficult to access, the authors of the new study used a 30-m long drill core to obtain samples of the sub-seafloor sediments from a depth of about 5500 m at a site in the Sargasso Sea in the North Atlantic. By analyzing the DNA fragments extracted from these sedimentary deposits - which are up to 15 million years old - they were able to identify the major classes of micro-organisms present in the strata. "And we made the astonishing discovery that members of the Archaea, and in particular the ammonia-oxidizing Thaumarchaea, were far more abundant in these samples than bacteria," says Orsi.

Further analyses showed that this specific group of Archaea possesses a highly efficient metabolic system, which enables them to survive in sub-seafloor sediments. In this low-energy environment they utilize protein fragments from dead cells for the construction of the metabolic and structural components they need. In addition, they make use of the ammonia produced by the degradation of proteins as the basis for another chemical reaction cycle, which provides them with energy. "We believe that this unique ability, in combination with an efficient system for the uptake and fixation of carbon, accounts for the dominance of the Thaumarchaea in these sediments," says Steven D'Hondt (University of Rhode Island, USA), the leader of the deep sea expedition.

Overall, the new results suggest that, in oxygen-bearing deep-sea sediments, Thaumarchaea convert inorganic carbon into biomass, and therefore serve as the basal level of the food chain.  This activity has lasted over long timescales, for at least 15 million years. "In this ecosystem, they have been outperforming bacteria for many millions of years," says Orsi, "and this may also hold in other ecological niches below the seafloor"

Research across several areas of the "Third Pole" - the high-mountain region centered on the Tibetan Plateau - shows a seasonal cycle in how near-surface temperature changes with elevation. Near-surface temperature, which reflects the energy balance at the land surface, is crucial because it drives climate processes.

The research was conducted by a team led by Dr. D. B. Kattel, a researcher at the Institute of Tibetan Plateau Research of the Chinese Academy of Sciences. It was published in Theoretical and Applied Climatology, with Dr. Kattel as the lead author.

The Third Pole stores more snow and ice than anywhere else in the world outside the Arctic and the Antarctic, thus earning it the "Third Pole" sobriquet.

The unique cryospheric (i.e., involving frozen water) processes at the Third Pole make the area particularly sensitive to global environmental changes. Slight changes in climate can result in large-scale melting of glaciers, permafrost and persistent snow, thus altering the land-surface energy balance at the Third Pole and air and water cycles in the region and beyond.

As many major Asian rivers originate from Third Pole glaciers - thus making the area the "water tower of Asia" - changes in such glaciers can be felt ecologically and economically through those rivers by almost one-fifth of the world's population across more than 10 countries.

In his most recent research, Dr. Kattel and his team examined 53 in situ climate records from Pakistan. Combining these data with climate records from Nepal, Bhutan and the southeastern Tibetan Plateau, the team identified different forces behind variations in near-surface temperature with elevation, time and space, thus offering a three-dimensional view of climatic behavior on the Third Pole.

For example, their research showed different factors controlling temperature variability in the northern and southern slopes of the Himalayas.

"The monsoon controls the near-surface temperature throughout the region during summer," said Dr. Kattel. "However, micro- and topoclimatic effects are [a stronger influence on] minimum temperature on the southern slopes and the maximum temperature on the northern slopes of the Himalayas."

These results provide a more accurate basis than earlier studies for modeling and prediction related to glacier movement, forestry as well as agriculture at the Third Pole, all of which are very sensitive to temperature.

Within the greater European project of the Quantum Flagship, spearheaded by Mikel Sanz - researcher of the QUTIS Group of the UPV/EHU Physical Chemistry Department - an experiment has been conducted in collaboration with German and Japanese researchers who have managed to develop a protocol for preparing a remote quantum state while conducting communication in the microwave regime, "which is the frequency at which all quantum computers operate. This is the first time the possibility of doing so in this range has been examined, which may bring about a revolution in the next few years in the field of secure quantum communication and quantum microwave radars", lead researcher in this project Mikel Sanz observes.

The preparation of a remote quantum state (known as remote state preparation) is based on the phenomenon of quantum entanglement, where sets of entangled particles lose their individuality and behave as single entities, even when spatially separated. "Thus, if two computers share this quantum correlation, performing operations on only one of them can affect the other. Absolutely secure communication can be achieved", Sanz explains.

Studies on this remote quantum state preparation protocol began some 20 years ago, but to date, communication had always been made over waves of the visible range. "This is because work in this range can be done at room temperature, since the thermal radiation from bodies, through the mere fact of being at room temperature, is extremely low in the optic range, so that interferences barely exist in such communication" --the researcher explains. "However, in the microwave regime, billions, trillions of photons at room temperature are generated, which destroy quantum properties, so that to avoid all that interference, these experiments must be done at near-absolute zero temperatures (0.05 Kelvin), to limit the radiation from bodies to the maximum and make communication effective".

After considerable work on developing this technology in order to perform the experiments, the team managed to prepare a remote quantum state over a distance of 35 centimetres. "This has served as a concept test, also known as proof of principle, a first step towards knowing that it is possible to continue developing this technology. However, we believe this is a very important first step that can bring about a revolution over the next decade", Dr. Sanz underscores.

The researcher points out two fields where this revolution could take place: "on the one hand, quantum communication or cryptography, since this would be absolutely secure, and not having to change the frequency to the optic range (as it is done nowadays) would prevent many losses in this communication. And on the other hand, ultra-accurate quantum metrology and quantum radars. The different radar applications are based on object detection, and this detection is done in microwave; and since there are devices like drones that are increasingly growing smaller, radars are required to have increasingly greater capacity for detecting them, in order to know where they are. The technology we are developing can help considerably in this regard".

These and many other applications that this technology is capable of cannot be conceived under temperatures as low as those in which it operates currently, so that "one of the project objectives is to attempt to make this technology work at room temperature. In the end, what we seek is to bring this technology to commercial products", Sanz concludes.

A research team of Tohoku University, Nissan Motor Co., Shinshu University, and Okayama University made a groundbreaking discovery in the quest to replace hydrofluorocarbons in refrigeration systems with natural refrigerants such as water and alcohol. Their study involved carrying-out a liquid-to-gas phase transition via a nanosponge, a soft, elastic material equipped with small nanopores less than 10 nanometers. Their findings could lead to more efficient refrigerants with a smaller carbon footprint.

Refrigeration systems are widely used in air conditioners and refrigerators. Conventional systems use hydrofluorocarbons as a refrigerant. However, hydrofluorocarbons are super pollutants. Their Global Warming Potential is about 1300 times higher than that of CO2.

The team of researchers successfully carried out a force-driven liquid-to-gas phase transition using a nanosponge. When a normal, wet sponge is squeezed, naturally, water is expected to come out. However, when using a nanosponge with a pore size of under 10 nanometers, a different phenomenon occurs. Even under low pressure, the sponge retains its liquid.

When applying force, however, the expelled liquid immediately evaporates into gas. Furthermore, as the sponge returns to its natural shape, it adsorbs the gas as a liquid into the nanopores again.

Until now, researchers have not carried out the squeezing process of nanoporous materials because conventional materials are too hard to be deformed. Nevertheless, the team circumvented this by creating their own soft, elastic, nanoporous materials, consisting of a single-layer of graphene walls. They measured their results using a home-made equipment designed to monitor liquid-gas phase transition when mechanical force is applied.

The team thought about the squeezing method after developing soft nanoporous materials. But even they could not anticipate their prediction becoming reality at the first attempt.

To date, there have been only two methods of converting trapped liquid into gas: i. heating or ii. decreasing the gas-phase pressure. The squeezing method provides a third way, generating a new theme in the field of physical chemistry and paving the path for more environmentally friendly refrigeration systems. Cool stuff!

A team of international experts including La Trobe University ecologist Nick Bond, led by the University of Canterbury, are calling for urgent global change to how we manage and model river ecosystems.

Professor Bond - Director of La Trobe's Centre for Freshwater Ecosystems - said a change in river management is vital as extreme weather events become more frequent and severe.

"This is something of a call to arms for a greater emphasis on assessing long-term risks and understanding how management decisions we make today might play out into the future," Professor Bond said.

"While extreme events such as floods and droughts are an integral part of the natural variability that shapes river ecosystems, as they grow more extreme and frequent, the capacity for populations to recover may be more difficult.

"Understanding those risks and identifying potential tipping points requires a greater understanding of how populations are affected, not just by individual events, but by changing regimes.

The call to action has been published in Nature.

University of Canterbury Rutherford Discovery Fellow Dr Jonathan Tonkin contends we can no longer solely aim to restore river ecosystems to historical or 'natural' states, because often, and increasingly, those states are themselves changing.

He says we are ill equipped to tackle river management challenges because current tools no longer work amid increasing climatic uncertainty.

"The world is changing so fast that we risk losing the services that river ecosystems provide to society. We need to move on from traditional approaches to managing rivers, to tools that can anticipate future shocks and manage adaptively to protect valuable species and ecosystem services," Dr Tonkin said.

Professor Bond said that while the necessary modelling approaches exist, they have rarely been used in river management.

"This is mainly because the necessary biological data is often lacking," Professor Bond said.

"Such data are costly for scientists and agencies to collect. For example, measuring survival and reproductive success can take years to measure, and thus requires long-term funding and commitment."

Dr Tonkin said new models of river management must be able to look into the future, where novel conditions are inevitable.

"We are losing freshwater biodiversity on our watch. The threats are stacking up, including from pollution, invasive species, and land-use change, and the amplifying effects of climate change," Dr Tonkin said.

Dr Tonkin has called for rivers to be managed adaptively and for researchers to develop forecasting tools that move beyond simply monitoring the state of ecosystems to establishing the biological mechanisms that underpin their survival.

"The reason we want to look into the future is to anticipate future conditions and proactively manage against extremes to avoid collapses in populations or ecosystems," Dr Tonkin said.

"In New Zealand and around the world we know rivers are under extreme pressure. In times of such rapid environmental change, we must manage rivers for resilience. Large fish kills and droughts are increasingly frequent globally, including in Australia's Murray-Darling Basin, Europe's Rhine River, and across California."

To limit the regularity of such events, Dr Tonkin and his colleagues want to see a greater uptake of adaptive approaches to managing river flows, and for greater emphasis to be placed on understanding the biological mechanisms by which species respond to rapid change.

By understanding these mechanisms, Dr Tonkin said scientists will be better able to foresee how management interventions will play out in the future, as well as how species will respond to unprecedented change.

"This paper is a call for the uptake of these approaches, in order to allow for a scientifically robust basis for managing for resilience in rivers under climate change," Dr Tonkin said.

"Rivers also need to be managed for people. So we have a major task ahead of us, requiring collaboration between scientists, conservationists, water managers, and policymakers."

In a paper to be published in the forthcoming issue in NANO, a team of researchers from Henan University have investigated the flame retardant performance of epoxy resin using a boron nitride nanosheet decorated with cobalt ferrite nanoparticle.

Polymers are widely used in our daily lives due to good physical and chemical stability, corrosion resistance and other superior properties. However, most polymers, due to their organic nature, are inherently flammable which has a potential threat to the safety of human life and property. In order to avoid or reduce the flammability of polymers, it is a good strategy to add flame retardants to the polymers.

Among them, two-dimensional (2D) layered inorganic nanomateirals (nanosheets), represented by graphene oxide, molybdenum disulfide, and boron nitride nanosheets (BNNS), exhibit excellent flame retardant performance due to their good physical barrier effects. However, the flame retardance is not enough in the use of such 2D inorganic flame retardants alone, and in particular, the ability to suppress toxic gases and smoke is weak.

In this study, authors used cobalt ferrite nanoparticle (CFN) to decorate BNNS in order to obtain CFN-BNNS nanohybrids with good potential for reducing both the heat hazard and toxic hazard of epoxy resin (EP) composites, by making use of CFN synergistic effect. More importantly, the as-prepared CFN-BNNS has superior paramagnetic properties, thereby accommodating the ordered orientation of BNNS in EP matrix under a weak magnetic field that can act as a good physical barrier. The ordered alignment of the CFN-BNNS in EP contributes to better flame retardant performance compared with random one. Namely, the flame retardant performance of the 2D flame retardants can be improved by the ordered alignment under a weak magnetic field. This technology provides a new approach to improve flame retardant performance of 2D flame retardants in thermoset polymer. This is the most significant novelty. And it will help researchers design and produce more polymers with excellent flame retardant performance through this method.

In a paper to be published in the forthcoming issue in NANO, a team of researchers from Nanchang University have attempted to directly engineer the surface structure of Cu-based substrate to get a series of Ce-O-Cu catalysts for NH3-SCR of NO. The obtained catalysts were structured as CuO matrix with interactive surface composed by Cu(I)-Cu(II) and Ce(III)-Ce(IV) co-present species, exhibiting the distinct synergistic effect and leading to attractive catalytic performance even with SO2 present in reactant mixture.

What is a feasible preparation strategy for engineering oxide composites with interactive structures for advanced heterogeneous catalysis? Here, an attempt to directly construct and manipulate Ce-O-Cu composited surface structures from the design of Ce(IV) to chemically embed Ce into the surface of Cu2O substrate was made, and the thermally-derived samples were investigated as catalysts for NH3 selective catalytic reduction (NH3-SCR) of NO.

The feature of surface structure of solid catalyst such as oxide composites was the decisive factor to govern the performance for heterogeneous catalysis reactions. However, the traditional preparation methods to construct oxide composites such as co-precipitation, sole-gel or solvothermal synthesis were not qualified to manipulate the surface structure of solid materials.

Unlike these body-mingling preparations from traditional methods, in this work, an attempt to directly construct and manipulate composited oxide surface upon a redox replacement preparation was made by employing Ce(IV) precursor to etch Cu2O in order to embed Ce species onto Cu-based oxide surface, and the catalysts derived from thermal stabilization treatments were investigated for NH3-SCR of NO. In principle, the standard potentials for two redox pairs [Ce(IV)/Ce(III)] and [Cu2O/Cu2+] were 1.72 V and 0.20 V, respectively, the lower potential of [Cu2O/Cu2+] pair means Cu2O would act as the reductant when it encountered the Ce(IV) species, i.e., Ce(IV) species could etch Cu2O to produce Cu2+ and Ce(III) species. Since Cu2+ would remove into aqueous solution, the left space on Cu-based solid substrate could facilitate the surface embedding of Ce species. Although Cu(II) contained compounds such as CuO that were always used as precursors or substrates, such Cu(II) compounds would not react with Ce ion species no matter whether Ce(IV) or Ce(III) was employed due to the thermodynamic limitation from the above redox potential disparity. Therefore, the design and preparation of Ce-O-Cu composited samples initiated from employing Ce(IV) contained Ce(NO3)62- ion to etch-embed Ce onto the surface of Cu2O substrate, followed by a thermal-stabilization processing to get catalysts.

With comprehensive characterizations, the design was demonstrated to be quite efficient in creating Cu(I)-Cu(II) and Ce(III)-Ce(IV) co-existed interactive surface on CuO matrix with ultra-low dosage of Ce (0.83-2.3 wt.%) in comparison with literature works. More interestingly, the surface metal species distributions, redox properties, active site distributions and strength, and surface reactivity could be sensitively and conveniently manipulated on such structures, which offered a chance to get superior catalytic performance such as higher NO conversion (≥90% with ≥95% selectivity to N2) below 300°C, fold-increased TOF, good catalytic durability even under the presence of SO2 on well-manipulated sample compared to Ce-Cu reference catalysts prepared from traditional method. All of the above catalytic results were obtained with gas hourly space velocity (GHSV) at 100,000 h-1, and more practical reaction conditions such as (SO2+H2O) co-presence were also imposed on our samples. The superior performance under these conditions together with novel structure and attractive physical chemistry properties of our samples suggest that chemically embedding preparation and derived structures could be a competitive solution to obtain efficient oxide composite materials for practical and advanced applications.

CINCINNATI--Scientists used a gene editing method called CRISPR/Cas9 to generate mice that faithfully mimic a fatal respiratory disorder in newborn infants that turns their lips and skin blue. The new laboratory model allowed researchers to pinpoint the ailment's cause and develop a potential and desperately needed nanoparticle-based treatment.

Mostly untreatable, Alveolar Capillary Dysplasia with Misalignment of Pulmonary Veins (ACDMPV) usually strikes infants within a month of birth, according researchers at Cincinnati Children's Hospital Medical Center, who publish findings in the American Journal of Respiratory and Critical Care Medicine. The disease starves the pulmonary system of oxygen after the lung's blood vessels don't form properly during organ development. The lack of tiny blood vessels called alveolar capillaries causes hypoxia, inflammation and death.

"There are no effective treatments other than a lung transplant, so the need for new therapeutics is urgent," said Vlad Kalinichenko, MD, PhD, at the Cincinnati Children's Perinatal Institute Center for Lung Regenerative Medicine and lead study investigator. "We identified a nanoparticle therapeutic strategy to increase the number of alveolar capillaries and help preserve respiratory function for at least a subset of the babies with this congenital lung disease."

The disease has long been linked to mutations in the FOXF1 gene, an important regulator of embryonic lung development. The remaining mystery until this study is precise microbiological processes that fuel ACDMPV, according to the researchers.

Uncovering the STAT3 Connection

In collaboration with the team of Pawel Stankiewicz, MD, at the Baylor College of Medicine in Houston, the Kalinichenko lab analyzed genetic information from human ACDMPV cases to generate the first clinically relevant animal model of ACDMPV. They used CRISPR/Cas9 to recreate human FOXF1 mutations in the mouse. CRISPR-Cas9 allows precise gene editing by using an enzyme to cut out specific sections of a DNA sequence and reattaching the loose ends at a desired point to change a cell's genetic makeup.

Having clinically accurate mouse models of disease ACDMPV allowed the scientists to overcome a longtime hurdle to understanding how the disease develops, authors write.

The work also relied on extensive bioinformatics analyses of clinical and laboratory data from biological tests. This includes a technique called ChIP-Seq (which analyzes protein-DNA interactions), and whole exome sequencing (which reveals the arrangement of all protein-coding regions of genes).

By studying protein-DNA interactions linked to the FOXF1 gene in pulmonary cells, study authors found a specific point mutation involving FOXF1 at the S52F DNA binding location of FOXF1's nuclear protein. The mutation blocked molecular signaling to multiple downstream target genes involved in formation of pulmonary blood vessels.

They also discovered that the S52F FOXF1 mutant protein did not interact with a protein called STAT3. The link is critical to stimulating the development of blood vessels in the neonatal lung. This led to a deficiency of STAT3 in developing lungs and improper formation of the pulmonary circulatory system.

Researchers also found STAT3 deficiency in donated samples from ACDMPV patients who had specific point mutations in the FOXF1 gene. The authors theorized that treating newborn mice with STAT3 would stimulate blood vessel development in the lungs, but they had to figure out how to get the protein to the lungs.

STAT3 Nanoparticle Solution

Researchers turned to nanoparticle technology to deliver a STAT3 mini-gene to lungs of newborn mice. They created a novel formulation for what are known as polyethylenimine (PEI) nanoparticles.

The gelatin-like PEI nanoparticles can carry therapeutic genetic material to different parts of the body by administering them to patients intravenously. Different formulations of PEI nanoparticles are currently being tested in clinical trials for adult cancer at other institutions, according to study authors.

Therapeutic administration of STAT3 DNA to newborn mice with the S52F FOXF1 mutation restored the ability of endothelial cells to form pulmonary blood vessels. This stimulated blood vessel growth in the animals and the formation of air sacs called alveolar.

"If the efficacy of PEI nanoparticles is confirmed in the clinical trials under way for adult cancer, PEI could be considered for STAT3 gene therapy in infants with ACDMPV," Kalinichenko said. "Considering that ACDMPV is a rare disease, a multicenter clinical trial would be needed to assess the efficacy of STAT3 gene therapy in ACDMPV newborns and infants."

The study's first author is Arun Pradhan, PhD, a researcher who works in the Kalinichenko laboratory.

Funding support for the study came from the National Institutes of Health (HL84151, HL141174, HL123490, HL137203, HL132849 and grants from the National Organization for Rare Disorders.

A University of Oklahoma physics group sheds light on a novel Mott state observed in twisted graphene bilayers at the 'magic angle' in a recent study just published in Physical Review Letters. OU physicists show the Mott state in graphene bilayers favors ferromagnetic alignment of the electron spins, a phenomenon unheard of in conventional Mott insulators, and a new concept on the novel insulating state observed in twisted graphene bilayers.

"We are trying to understand the nature of the Mott state in this system," said Bruno Uchoa, associate professor in the Homer L. Dodge Department of Physics and Astrophysics. "The Mott state we proposed is an insulating state that may lead to superconductivity in some conditions, yet is different from Mott states observed in other systems. There are fundamental differences, however, and this is what we are studying."

Mott physics has been extensively investigated in the last decades in high-temperature cuprate superconductors - materials that in some conditions can transmit charge currents at relatively high temperature without producing any heat dissipation. In the Mott phase, however, the motion of charge carriers is confined by their strong mutual electric repulsion, which leads to insulating behavior, when a material is unable to conduct any electricity.

It also leads to anti-ferromagnetism, a state where the spins of two electrons sitting next to each other are anti-parallel. The latter property is the result of the Pauli exclusion principle, one of the many exotic properties of quantum mechanics, which states that the two electrons cannot occupy the same quantum state. The new study shows that the Mott state in graphene departs from other known examples in fundamental ways.

Using two sheets of graphene twisted at a very small angle, known as the 'magic angle,' the system correlates with properties seen in high-temperature superconductors. Graphene is made of carbon and the thinnest material in the universe, only one atom thick. The material is like a honeycomb lattice, so two layers twisted at a very small angle result in the electrons moving differently. The new work shows that lattice constraints imposed by the small twist angle can strongly favor parallel alignment of the electronic spins even when electrons are strongly repelling each other. The OU physicists proposed a novel Mott state where these electrons behave in ways not seen before.

"Twisted graphene bilayers are very promising for a variety of technological applications in nanodevices," said Kangjun Seo, a postdoctoral researcher in the OU group, who was first author on the study. "This is a very interesting and important physical system."

New evidence shows that Arctic ecosystems undergo rapid, strong and pervasive environmental changes in response to climate shifts, even those of moderate magnitude, according to an international research team led by the University of Maine.

Links between abrupt climate change and environmental response have long been considered delayed or dampened by internal ecosystem dynamics, or only strong in large magnitude climate shifts. The research team, led by Jasmine Saros, associate director of the UMaine Climate Change Institute, found evidence of a "surprisingly tight coupling" of environmental responses in an Arctic ecosystem experiencing rapid climate change.

Using more than 40 years of weather data and paleoecological reconstructions, the 20-member team quantified rapid environmental responses to recent abrupt climate change in West Greenland. They found that after 1994, mean June air temperatures were 2.2 degrees C higher and mean winter precipitation doubled to 40 millimeters. Since 2006, mean July air temperatures shifted 1.1 degree C higher.

The "nearly synchronous" environmental response to those high-latitude abrupt climate shifts included increased ice sheet discharge and dust, and advanced plant phenology. In lakes, there was earlier ice-out and greater diversity of algal functional traits.

The new evidence underscores the highly responsive nature of Arctic ecosystems to abrupt transitions -- and the strength of climate forcing, according to the team, which published its findings in the journal Environmental Research Letters.

Understanding how ecosystems respond to abrupt climate change is central to predicting and managing potentially disruptive environmental shifts, says Saros, one of seven UMaine professors who have been conducting research in the Arctic in recent years.

"We present evidence that climate shifts of even moderate magnitude can rapidly force strong, pervasive environmental changes across a high-latitude system," says Saros. "Prior research on ecological response to abrupt climate change suggested delayed or dampened ecosystem responses. In the Arctic, however, we found that nonlinear environmental responses occurred with or shortly after documented climate shifts in 1994 and 2006."

CHAMPAIGN, Ill. -- Newly developed geological techniques help uncover the most accurate and high-resolution climate records to date, according to a new study. The research finds that the standard practice of using modern and fossil coral to measure sea-surface temperatures may not be as straightforward as originally thought. By combining high-resolution microscopic techniques and geochemical modeling, researchers are using the formational history of Porites coral skeletons to fine-tune the records used to make global climate predictions.

The new findings are reported in the journal Frontiers in Marine Science.

For over 500 million years, corals have been passively keeping track of changing sea-surface temperature by recording the ratio of calcium to strontium and oxygen isotopes within their skeletons, the researchers said. The coral skeletons - which are made of calcium carbonate mineral - grow layers like tree rings that have increased amounts of strontium and the lighter isotope of oxygen during the warmer season. Climate scientists take advantage of this process to track sea surface temperature through time.

However, this climate-tracking technique is not without its flaws, said University of Illinois geology and microbiology professor Bruce Fouke, who led the new research.

"We can ground truth coral-based sea-surface temperature records against records made using temperature probes," Fouke said, "Remarkably, the coral records are accurate most of the time, but there are instances where measurements have been off by as much as nine degrees Celsius, and this needs to be rectified."

To grow their skeletons, coral polyps deposit aragonite. However, the mineral also crystalizes from seawater, the researchers said, and that can cause problems when analyzing the original coral skeleton chemistry. As seawater flows through the porous coral structure, it deposits newly crystalized aragonite on top of skeletons. That new aragonite, which may record a different sea-surface temperature, alters original skeletal chemistry through a process called diagenesis, Fouke said.

"It is difficult to tell the diagenetic aragonite from the original coral skeleton without using high-powered microscopes," said Kyle Fouke, a Bucknell University undergraduate student, Carl R. Woese Institute for Genomic Biology affiliate and co-author of the study. "It is also challenging to know exactly when the diagenetic alteration took place - days or decades after the skeletons were formed. Unless you are using the newest microscopy techniques to help select your samples, you could be collecting and measuring a mix of the two very different temperature records."

To test this, the team collected drill cores from the skeletons of living Porites coral heads at 10 to 100 feet water depth on the Great Barrier Reef off the coast of Australia. These large coral heads reach nearly 10 feet in diameter, and some have been growing for hundreds of years.

"Based on our analyses, we see that the older portions of the coral heads growing in deeper seawater contain a higher concentration of diagenetic aragonite," Kyle Fouke said.

"Using a broad array of light, electron and X-ray microscopy techniques - made available under the direction of study co-author Mayandi Sivaguru, an associate director at the Carl R. Woese Institute for Genomic Biology Microscopy Core at the U. of I. - we were able to clearly differentiate between the original skeleton and diagenetic aragonite, when present," said Lauren Todorov, a molecular and cellular biology undergraduate student and study co-author.

Using these techniques, the team uncovered a multitude of different aragonite crystallization histories, ranging from seasonal variations in skeletal growth to smaller-scale processes that could be occurring on daily - even hourly - cycles.

By taking the extra steps to sort out the relative timing between the skeletal and diagenetic aragonite crystallization, the team integrated its data with chemical-mixing models for calcium, strontium and oxygen isotopes from geochemical studies of Porites from Papua New Guinea. From this, the team created the first reliable and reproducible correction factor that determines the magnitude of error that diagenetic alteration can place on sea-surface temperature measurements.

"Additionally, because this has been achieved using the carbonate mineral aragonite, which is ubiquitous among marine life, this same correction factor can be used with other sea creatures that secrete carbonate skeletons and shells," Bruce Fouke said.

Sea-surface temperature records derived from coral skeleton chemistry are the gold standard for accurate climate reconstructions and future predictions, the researchers said, and this new insight only further strengthens this tool.

Underneath their tough exteriors, some crocodilians have a sensitive side that scientists could use to shine light on our ancient climate, according to new findings published in the Journal of Vertebrate Paleontology.

The idea of a clock inside a crocodile was imagined by JM Barrie in the story of Peter Pan, but instead of telling the current time, ancient crocodilians could serve as climate "clocks" - proxies to study past climates, in a similar way to the use of tree rings and ice cores.

This is possible because scientists have discovered that some species of crocodilian were sensitive to changes in climate while others were more tolerant. Mapping the distribution of these different species using fossil remains could reveal more precise details about what the global climate was like in different locations millions of years ago.

"Our analysis suggests that crocodilians are even less of a homogenous group than previously thought and that some alligator-like reptiles were particularly good at tolerating the dramatic changes in climate that marked the end of the Eocene epoch and the beginning of the Oligocene," says lead author Dr Stéphane Jouve from the University of Sorbonne.

The transition between these epochs was marked by a climatic crisis, during which temperatures plummeted, sea levels fell drastically and many plants and animals became extinct as a result. Previous studies have suggested that crocodilians were one of the species to decline in diversity, but the new fossil analysis suggests that while some species did die out, others migrated to warmer waters and some managed to survive.

The coastal environment was transformed by the decline in sea level and some marine
longirostrine crocodilians escaped the cold of Europe by migrating south to North Africa. The palaeontologists suggest that Morocco could have been the platform for other marine species, in the gavialoid family, to migrate to South America. Meanwhile, the marine tomistomines, a family of crocodilians whose distribution once included England, progressively disappeared from north to south, as the freeze continued.

Freshwater species were not affected by sea level but some couldn't survive the rapid decline in temperatures of the late Eocene and became extinct. Meanwhile, the alligator-like freshwater Diplocynodon continued to survive even the lowest temperatures of the early Oligocene epoch. Compared to the gavialoids and tomistomines, it survived a large range of latitudes, from Spain to cooler England.

The roles of "climate change" versus "tectonics" that dominate erosion and sediment transport over geological time scales have long been a hot topic in Earth science. How to effectively separate their respective roles is a big challenge, like the famous "chicken or egg" question.

A new study led by Prof. JIN Zhangdong from the Institute of Earth Environment (IEE) of the Chinese Academy of Sciences provided a new insight on the interplay between climate and tectonics from a sediment record in the Zipingpu Reservoir around the 2008 Wenchuan earthquake. The findings were published in Science Advances on June 12.

Infrequent extreme events such as large earthquakes pose hazards and have lasting impacts on landscapes and biogeochemical cycles. Sediments provide valuable records of past events, but unambiguously identifying event deposits is challenging because of nonlinear sediment transport processes and poor age control.

The Zipingpu Reservoir, with annually resolved sediments, provides a unique opportunity to document the link between a large earthquake and its sedimentary signature, because it was completed in September 2004 and is located downstream of the area impacted by the 2008 Wenchuan earthquake.

In October 2016, a 10.89-m sediment core back to the river bed was recovered from the Zipingpu Reservoir. An age model for the core was developed based on the correlation between sedimentary magnetic susceptibility and reservoir water level. The boundary of the 2008 Wenchuan earthquake was then assigned to the core depth of 6.20 m (Fig. 1). This is the first time that a 10-year sediment core was dated to annual resolution.

Based on the precise annual chronology, the roles of a single large earthquake and climate on erosion and sediment transfer were evaluated along with sedimentary and hydrometeorological data. The records demonstrated that the grain size and Rb/Sr ratios of the sediments in the Zipingpu Reservoir responded immediately to the earthquake. However, the changes were muted until two years after the event.

The most obvious seismic signals occurred in 2010 when intense monsoonal runoff facilitated fast material export and drove accumulation of coarser grains and lower Rb/Sr sediments, which were then sustained for several years (Fig. 2).

The results indicated that, although the earthquake mobilized very large amounts of sediment by landsliding, hydrological forcing was necessary to transport this debris from hillslopes to downstream sediment stores, even in a location proximal to the mountain front.

The delayed response highlighted the role of intense monsoonal rainfall in propagating tectonic signals into sedimentary archives.

This study provides direct evidence that can inform the interpretation of paleorecords and help to illuminate the ways in which sedimentary archives reflect the complex interaction of tectonics and climate in controlling sediment transfer in tectonically active mountain ranges.

A groundbreaking drug that helps regulate bone development has boosted growth rates in children with achondroplasia - the most common type of dwarfism - in a global trial led by Melbourne's Murdoch Children's Research Institute.

Results of the Phase 2 trial in children aged five to 14 years are published today (Tuesday, June 18) in the New England Journal of Medicine. The project is now in Phase 3 to test the drug, vosoritide, in a larger group of patients aged 5 to 18 years.

Lead author and MCRI clinical geneticist Professor Ravi Savarirayan, said achondroplasia is caused by overactivity of a signal that stops growth, and could be likened to overwatering a plant.

"This drug basically kinks the hose so that the plant gets the right amount of water and can resume regular growth," Prof. Savarirayan said.

Achondroplasia is a genetic bone disorder affecting about one in every 25,000 infants. It is caused by a mutation in the FGFR3 gene that impairs the growth of bones in the limbs, the spine, and base of the skull.

The most common health complications experienced by children with achondroplasia are spinal cord compression, spinal curvature and bowed legs. About half of these children will need spinal or other surgery.

"This can mean a lot of time away from school as the child recovers and rehabilitates after surgery, which can affect important social connections," Prof Savarirayan said.

Unlike other treatments - such as growth hormone and limb-lengthening surgery - that focus on symptoms, vosoritide focuses on the underlying cause of achondroplasia and directly counteracts the effect of the mutation that slows growth.

The study ran over four years across research centres in Australia, France, UK and USA with 35 children assigned to one of four groups receiving daily subcutaneous doses of the drug in increasing amounts.

Co-author Associate Professor and Director of the Greenberg Center for Skeletal Dysplasias at the Johns Hopkins McKusick-Nathans Institute of Genetic Medicine, Julie Hoover, said the patients' average boost in height to about 6 centimetres (2.4 inches) per year was close to growth rates among children of average stature, and the side effects of the drug were mostly mild.

"Right now, the results of the study show an impact on growth, and this effect is sustained, at least over nearly four years in this trial," A/Prof Hoover said. "The potential long-term benefit will take more time to observe."

The main aims of the Phase 2 trial were to evaluate safety and tolerability of the drug and to determine the best dose for the Phase 3 trials, which are now underway.

The results showed vosoritide was generally well tolerated by patients and demonstrated dose-dependent increases in centimetres grown per year during the first six months, with improvements maintained over the study extension period of a further three years.

On average, participants in the trial grew at a 50 per cent faster compared to baseline with no adverse effects on body proportion. Overall bone age was not accelerated implying that this effect, if sustained long-term, might increase final adult height.

"This study is the very first report of a possible disruptive, precision therapy for children with achondroplasia, which we hope will improve their health outcomes and functioning, as well as increase their height and access to their environment", Prof Savarirayan said. Currently management of the medical complications of achondroplasia is predominantly surgical.

A placebo-controlled trial of vosoritide in younger children aged 0 to five years that is currently underway may help researchers shed light on the effects of earlier treatment on body proportion and other age-related complications such as compression of the spinal cord as it exits the skull, which can cause sudden death in this condition if not treated.