Heavens

Natural diamonds can form through low pressure and temperature geological processes on Earth, as stated in an article published in the journal Geochemical Perspectives Letters. The now found mechanism, far from the classic regard on the formation of diamonds under ultra-high pressure, is confirmed in the study, which counts on the participation of experts from the Mineral Resources Research Group of the Faculty of Earth Sciences of the University of Barcelona (UB).

Other participants in the study are the experts from the Institute of Nanoscience and Nanotechnology of the UB (IN2UB), the University of Granada (UGR), the Andalusian Institute of Earth Sciences (IACT), the Institute of Ceramics and Glass (CSIC), and the National Autonomous University of Mexico (UNAM). The study has been carried out within the framework of the doctoral thesis carried out by researcher Núria Pujol-Solà (UB), first author of the article, under the supervision of researchers Joaquín A. Proenza (UB) and Antonio García-Casco (UGR).

Diamond: the toughest of all minerals

A symbol of luxury and richness, the diamond (from the Greek αδ?μας, "invincible") is the most valuable gem and the toughest mineral (value of 10 in Mohs scale). It formed by chemically pure carbon, and according to the traditional hypothesis, it crystalizes the cubic system under ultra-high-pressure conditions at great depths in the Earth's mantle.

The study confirms for the first time the formation of the natural diamond under low pressures in oceanic rocks in the Moa-Baracoa Ophiolitic Massif, in Cuba. This great geological structure is in the north-eastern side of the island and is formed by ophiolites, representative rocks of the Oceanic lithosphere.

These oceanic rocks were placed on the continental edge of North America during the collision of the Caribbean oceanic island arch, between 70 and 40 million years ago. "During its formation in the abysmal marine seafloors, in the cretaceous period -about 120 million years ago-, these oceanic rocks underwent mineral alterations due to marine water infiltrations, a process that led to small fluid inclusions inside the olivine, the most common mineral in this kind of rock", note Joaquín A. Proenza, member of the Department of Mineralogy, Petrology and Applied Geology at the UB and principal researcher of the project in which the article appears, and Antonio García-Casco, from the Department of Mineralogy and Petrology of the UGR.

"These fluid inclusions contain nanodiamonds -of about 200 and 300 nanometres-, apart from serpentine, magnetite, metallic silicon and pure methane. All these materials have formed under low pressure (

"Therefore, this is the first description of ophiolitic diamond formed under low pressure and temperature, whose formation under natural processes does not bear any doubts", they highlight.

Diamonds formed under low pressure and temperature

It is notable to bear in mind that the team published, in 2019, a first description of the formation of ophiolitic diamonds under low pressure conditions (Geology), a study carried out as part of the doctoral thesis by the UB researcher Júlia Farré de Pablo, supervised by Joaquín A. Proenza and the UGR professor José María González Jiménez. This study was highly debated on among the members of the international scientific community.

In the published article in Geochemical Perspectives Letters, a journal of the European Association of Geochemistry, the experts detected the nanodiamonds in small fluid inclusions under the surface of the samples. The finding was carried out by using the confocal Raman maps and using focused ion beams (FIB), combined with transmission electron microscopy (FIB-TEM). This is how they could confirm the presence of the diamond in the depth of the sample, and therefore, the formation of a natural diamond under low pressure in exhumed oceanic rocks. The Scientific and Technological Centres of the UB (CCiTUB) have taken part in this study, among other infrastructures supporting the country.

In this case, the study focuses its debate on the validity of some geodynamic models that, based on the presence of ophiolite diamonds, imply circulation in the mantle and large-scale lithosphere recycling. For instance, the ophiolitic diamond was thought to reflect the passing of ophiolitic rocks over the deep earth's mantle up to the transition area (210-660 km deep) before settling into a normal ophiolite formed under low pressure (~10 km deep).

According to the experts, the low state of oxidation in this geological system would explain the formation of nano-çdiamonds instead of graphite -which would be expected under physical and chemical formation conditions of fluid inclusions.

The study counted on the support from the former Ministry for Economy and Competitiveness (MINECO), the Ramón y Cajal Program and the EU European Regional Development Fund (ERDF).

To understand the significance of the Spitzer Space Telescope on the understanding of our solar system, think of what the steam engine meant for the industrial revolution.

A national team of scientists today published in the journal Nature Astronomy two papers that provide an inventory of the major discoveries made possible thanks to Spitzer and offer guidance on where the next generation of explorers should point the James Webb Space Telescope (JWST) when it launches in October 2021.

"The Spitzer Space Telescope made many important discoveries in the solar system during its 16 year-long mission, and it is important to capture the highlights of these with useful references for future scientists to use in their research," says Carey M. Lisse, from the Johns Hopkins Applied Physics Lab, lead author of one paper.

Lisse, a planetary astronomer, put together the team of 27 authors who penned the legacy papers. The authors were selected based on the significant discoveries they made using Spitzer during its 16-year mission. The team includes three University of Central Florida researchers, who offer suggestions for the next space telescope mission.

David Trilling, a planetary scientist and professor at Northern Arizona University, is the lead author on the second paper.

When Spitzer launched in 2003 it contained infrared detectors of unprecedented sensitivity, providing astronomers a never-before-possible look at the universe. Thanks to observations by Spitzer over the years, scientists gained new insights into, for example, the composition of comets, the icy surfaces of cold, distant bodies beyond Neptune, the heat radiation given off by asteroids, the extent of free-floating dust in the inner solar system, and the composition and properties of the atmospheres of Uranus and Neptune. Spitzer even managed to discover a new ring of Saturn! The much-delayed JWST, which will likewise study the infrared cosmos, is expected to build on the extensive results provided by Spitzer, including taking the next step in our study of the solar system.

UCF Professor Yan Fernandez, who specializes in comets, said the papers include some of the projects he is most proud off in his career. Fernandez is a co-author on both papers.

"I think these papers demonstrate the return on investment for Spitzer," Fernandez said. "These space telescopes are taxpayer-funded, after all. More philosophically, Spitzer has brought us closer to those big questions about why the solar system and Earth are here in the first place. Spitzer was not only great for the solar system, but it was great for studying exoplanets, great for studying planet formation, and great for studying star formation. All important to understand why our solar system turned out the way it did."

Noemí Pinilla-Alonso said astronomy is based on patience and collaboration. She studies Trans-Neptunian Objects at UCF's Florida Space Institute and contributed to the paper alongside institute post-doctoral scholar Estela Fernández-Valenzuela. Pinilla-Alonso is among a handful of scientists already guaranteed time on JWST once it is place. She is part of the team that will be calibrating the instrument from the ground.

"Answering one question takes the effort of multiple scientists or groups, each of them with a unique set of skills," Pinilla-Alonso says. "My contribution to this work is to provide the basic recipe of which ingredients are needed to build or cook an icy body in the solar system. And this is a key piece of information that is needed to answer questions such as how did the solar system form? How has it evolved to its actual state? How similar or different is our solar system from the long list, more than 3,000, of exoplanetary systems discovered?"

Fernandez-Valenzuela also studies Trans-Neptunian Objects and earlier this year held workshops to help scientists prepare successful proposals to obtain time on the JWST once NASA opens up the process.

"This work has helped us to understand what we could do with Spitzer data and how to use the JWST capabilities to shed light on issues that Spitzer could not answer," Fernández-Valenzuela says.

"Using Spitzer we have been able to detect specific materials that were impossible to detect from ground-based telescopes, due to the atmosphere, or using the Hubble Space Telescope," Fernández-Valenzuela says. "Now with JWST we will be able to obtain information on much fainter objects than is currently possible. I'm eager for that day as it will be a very important milestone for this research area. It will provide much more information on the formation of the outer solar system."

Spitzer was turned off in January 2020, 11 years beyond its prime mission.

"Spitzer was sensitive to infrared radiation, as opposed to visible light," Trilling says. "In many ways, Spitzer provided a view of the universe and of planetary bodies in our solar system that scientists had never seen before. This technological revolution produced new insights into the formation and evolution of our Solar System."

LA JOLLA--(October 7, 2020) Imagine that you're late for work and desperately searching for your car keys. You've looked all over the house but cannot seem to find them anywhere. All of a sudden you realize your keys have been sitting right in front of you the entire time. Why didn't you see them until now?

Now, a team of Salk Institute scientists led by Professor John Reynolds has uncovered details of the neural mechanisms underlying the perception of objects. They found that patterns of neural signals, called traveling brain waves, exist in the visual system of the awake brain and are organized to allow the brain to perceive objects that are faint or otherwise difficult to see. The findings were published in Nature on October 7, 2020.

"We've discovered that faint objects are much more likely to be seen if visualizing the object is timed with the traveling brain waves. The waves actually facilitate perceptual sensitivity, so there are moments in time when you can see things that you otherwise could not," says Reynolds, senior author of the paper and holder of the Fiona and Sanjay Jha Chair in Neuroscience. "It turns out that these traveling brain waves are an information-gathering process leading to the perception of an object."

Scientists have studied traveling brain waves during anesthesia but dismissed the waves as an artifact of the anesthesia. Reynolds' team, however, wondered if these waves exist in the visual part of the brain while awake and if they play a role in perception. They combined recordings in the visual cortex with cutting-edge computational techniques that enabled them to detect and track traveling brain waves.

"In order to understand the neural mechanisms of perception, we needed to develop new computational techniques to track neuronal activity in the visual cortex moment by moment," says co-first author Lyle Muller, BrainsCAN-funded assistant professor in the Department of Applied Mathematics and the Brain and Mind Institute at Western University in Ontario, Canada, and previously a postdoctoral fellow in the Sejnowski lab at Salk. "We then used these computational methods to uncover what change was occurring in the nervous system to suddenly allow for object recognition."

The scientists recorded the activity of the neurons from an area of the brain that contained a complete map of the visual world. They then tracked the trajectories of the traveling brain waves during a visual perception task. The scientists held an onscreen target at the threshold of visibility, so that observers could only detect the object 50 percent of the time, and recorded when the target was spotted. Since the target was not changing, the researchers reasoned that the observer's ability to perceive the object only half of the time had to be due to some change in the neural signals inside the brain.

They found that the brain's ability to recognize targets was directly related to when and where the traveling brain waves occurred in the visual system: when the traveling waves aligned with the stimulus, the observer could detect the target more easily. These traveling brain waves, which occurred several times per second, were similar to a stadium of sports fans successively standing up and raising their arms, then lowering them and sitting down again. It appears that the visual system is actively sensing the external environment, according to the team.

"There is a spontaneous level of activity in the brain that appears to be regulated by these traveling waves," says Salk Professor Terrence Sejnowski, an author of the paper and holder of the Francis Crick Chair. "We think the waves are the product of the activity that is propagating around the brain, driven by local neurons firing."

"We go about our everyday lives thinking that we are accurately seeing the world, but, in fact, our brains are filling in details that are difficult to see," says Zac Davis, co-first and corresponding author of the paper and a Salk postdoctoral fellow in the Reynolds lab. "Now, we have discovered how the brain weaves together hard-to-see information to perceive an object."

In the future, the scientists plan to examine whether these brain waves are coordinated across different brain regions devoted to vision. The researchers theorize that the brain waves could serve as a gate between the sensory processing and conscious perception that emerges from the brain as a whole.

Diamond could conduct electricity like metals when it is deformed to strains at the nanoscale, according to predictions from a study by an international team of scientists led by Nanyang Technological University, Singapore (NTU Singapore) and the Massachusetts Institute of Technology (MIT), USA.

Using computer simulations, the team, which also includes researchers from the Skolkovo Institute of Science and Technology (Skoltech), Russia, has shown as an early proof-of-concept that mechanical strain applied to nanoscale diamond needles could reversibly alter their geometry and hence their electrical properties, giving them a metal-like conductivity at room temperature and pressure.

The study published in the journal Proceedings of the National Academy of Sciences of the United States of America on 6 October 2020, could lead to future applications in power electronics used in a wide variety of machines from cars and electrical appliances to smart grids; highly efficient light emitting diodes (LEDs); optical devices; and quantum sensing, which enhances and improves what sensors can currently do.

The corresponding authors of this study are NTU President Professor Subra Suresh, MIT Professor Ju Li and MIT Principal Research Scientist Ming Dao. The list of authors includes Zhe Shi, graduate student at MIT, and Evgenii Tsymbalov and Professor Alexander Shapeev at Skoltech.

This finding follows an experimental discovery by an NTU-Hong Kong-MIT team of scientists led by Professor Suresh, who reported in a 2018 paper published in Science that diamond nano-needles - each about a thousand times thinner than a strand of human hair - can be bent and stretched substantially, so that they snap back without being damaged when the strain is released.

Diamond's exceptionally high hardness and stiffness, along with its many extreme physical properties, make it a desirable candidate material for a wide variety of applications. The new findings also pave the way for novel applications of diamond in the areas of quantum information, power electronics, and photonics, including the design of quantum sensors, highly efficient photo detectors and emitters, and applications in biomedical imaging.

Prof Suresh, who is also NTU Distinguished University Professor, said: "The ability to engineer and design electrical conductivity in diamond without changing its chemical composition and stability offers unprecedented flexibility to custom-design its functions. The methods demonstrated in this work could be applied to a broad range of other semi-conductor materials of technological interest in mechanical, microelectronics, biomedical, energy and photonics applications, through strain engineering."

From insulator to metal-like conductor

Materials that let an electric current pass through easily are known as electrical conductors, while materials such as diamond that do not are called electrical insulators.

Diamond in most forms is a good electrical insulator due to its ultrawide bandgap of 5.6 electron volts (eV). This means that a large amount of energy is needed to excite the electrons in the material before they can act as carriers in an electric current. The smaller the bandgap, the easier it is for a current to flow.

Using computer simulations that involved quantum mechanics, analyses of mechanical deformation, and machine learning, the scientists found that they can narrow this bandgap by elastically deforming the diamond nano-needle, by bending it as a diamond probe pushed it from the side.

They showed that as the amount of strain on the diamond nano-needle increased, its predicted bandgap narrowed - an indicator of greater electrical conductivity. The bandgap completely disappeared near the maximum amount of strain the needle could withstand before it would fracture. They further showed that such metallisation of diamond at the nanoscale could be achieved without triggering phonon instability or phase transformation from diamond to graphite, the soft material in pencils.

The researchers then used the simulation results to train machine learning algorithms to identify general conditions for achieving optimal electrical conductivity of nano-scale diamond in various geometrical configurations. This scientific research, still at the early stage, shows opportunities for further development of potential devices with unprecedented properties and performance.

Co-author and MIT Professor Ju Li said: "We found that it's possible to reduce the bandgap from 5.6 eV all the way to zero. The point of this is that if you can change continuously from 5.6 to zero eV, then you cover all the range of bandgaps. Through strain engineering, you can make diamond have the bandgap of silicon, which is most widely used as a semi-conductor, or gallium nitride, which is used for LEDs. You can even have it become an infrared detector or detect a whole range of light all the way from the infrared to the ultraviolet part of the spectrum."

The many millions of bodies populating the Kuiper Belt beyond Neptune's orbit are yet to reveal many of their secrets. In the 1980s, the space probes Pioneer 1 and 2 as well as Voyager 1 and 2 crossed this region - but without cameras on board. NASA's spacecraft New Horizons sent the first images from the outermost edge of the solar system to Earth: in the summer of 2015 of dwarf planet Pluto and three and a half years later of the trans-Neptunian object Arrokoth, about 30 kilometers in size. Not yet officially named, the body was nicknamed Ultima Thule at the time, in reference to the northernmost land point on Earth. After all, the trans-Neptunian object is the body furthest away from the Sun that has ever been visited and imaged by a man-made probe.

Especially Arrokoth's strange shape caused a sensation in the days after the fly-by. The body is a contact binary, believed to be a result of low velocity merging of two separate bodies that formed close together. It is composed of two connected lobes, of which the smaller one is slightly flattened, the larger one strongly so, creating the impression of a squashed snowman. In their current publication, the researchers from China, Germany, and the USA investigate how this shape came to be. A pronounced bi-lobed shape is also known from some comets. However, there is no other known body that is as flat as Arrokoth. Did Arrokoth already look like this when it was created? Or did its shape develop gradually?

"We like to think of the Kuiper Belt as a region where time has more or less stood still since the birth of the Solar System," explains Dr. Ladislav Rezac from MPS, one of the two first authors of the current publication. More than four billion kilometers away from the Sun, the bodies of the Kuiper Belt have remained frozen and unchanged, so is the common belief. New Horizon's images of Arrokoth challenge this idea by its apparently smooth surface without signs of frequent cratering events and by its peculiar, flattened shape. Scientists assume that the Solar System was formed 4.6 billion years ago from a disk of dust: the particles from this nebula agglomerated into ever larger clumps; these clumps collided and merged into even larger bodies. "There is as yet no explanation as to how a body as flat as Arrokoth could emerge from this process," says Rezac.

Another possibility would be that Arrokoth had a more ordinary shape to begin with. It may have started as a merger between a spherical and an oblate body at the time of its creation and only gradually become flattened. Earlier studies suggest that during the formation of the Solar System, the region where Arrrokoth is located could have been a distinct environment in the cold, dust-shaded mid-plane of the outer nebula. The low temperatures enabled volatiles such as carbon monoxide and methane to freeze onto dust grains and compose planetesimals. When the nebular dust cleared after Arrokoth's formation, solar illumination would have raised its temperature and hence rapidly driven off the condensed volatiles. Arrokoth's strange shape would then be a natural outcome due to a favorable combination of its large obliquity, small eccentricity and mass-loss rate variation with solar flux, resulting in nearly symmetric erosion between north and south hemispheres.

"For a body to change its shape as extremely as Arrokoth, its rotational axis needs to be oriented in a special way", Rezac explains. Unlike Earth's rotational axis, Arrokoth's is almost parallel to the orbital plane. During its 298 year orbit around the Sun, one polar region of Arrokoth faces the Sun continuously for nearly half the time while the other faces away. Regions at equator and lower latitudes are dominated by diurnal variations year round. "This causes the poles to heat up the most, so that frozen gases escape from there most efficiently resulting in a strong mass loss," says Dr. Yuhui Zhao from the Purple Mountain Observatory of the Chinese Academy of Sciences. The flattening process most likely occurred early in the evolution history of the body and proceeded rather quickly on a timescale of about one to 100 million years during the presence of super volatile ices in the near subsurface layers. In addition, the scientists self-consistently demonstrated that the induced torques would play a negligible role in the planetesimal's spin state change during the mass loss phase.

"How many of such 'flattened snowman' bodies are in the Kuiper Belt depends primarily on the probability of a body having a spin-axis inclination similar to Arrokoth's and on the amount of super-volatile ices present near its subsurface", Rezac says. There are reasons to believe that even objects like Arrokoth had considerable amounts of super-volatiles that have escaped during its early evolution. For instance, Pluto, due to its size and stronger gravity retains carbon monoxide, nitrogen and methane gasses even today. In the case of smaller bodies, these volatiles would long have escaped into space.

A study of comet motions indicates that the Solar System has a second alignment plane. Analytical investigation of the orbits of long-period comets shows that the aphelia of the comets, the point where they are farthest from the Sun, tend to fall close to either the well-known ecliptic plane where the planets reside or a newly discovered "empty ecliptic." This has important implications for models of how comets originally formed in the Solar System.

In the Solar System, the planets and most other bodies move in roughly the same orbital plane, known as the ecliptic, but there are exceptions such as comets. Comets, especially long-period comets taking tens-of-thousands of years to complete each orbit, are not confined to the area near the ecliptic; they are seen coming and going in various directions.

Models of Solar System formation suggest that even long-period comets originally formed near the ecliptic and were later scattered into the orbits observed today through gravitational interactions, most notably with the gas giant planets. But even with planetary scattering, the comet's aphelion, the point where it is farthest from the Sun, should remain near the ecliptic. Other, external forces are needed to explain the observed distribution. The Solar System does not exist in isolation; the gravitational field of the Milky Way Galaxy in which the Solar System resides also exerts a small but non-negligible influence. Arika Higuchi, an assistant professor at the University of Occupational and Environmental Health in Japan and previously a member of the NAOJ RISE Project, studied the effects of the Galactic gravity on long-period comets through analytical investigation of the equations governing orbital motion. She showed that when the Galactic gravity is taken into account, the aphelia of long-period comets tend to collect around two planes. First the well-known ecliptic, but also a second "empty ecliptic." The ecliptic is inclined with respect to the disk of the Milky Way by about 60 degrees. The empty ecliptic is also inclined by 60 degrees, but in the opposite direction. Higuchi calls this the "empty ecliptic" based on mathematical nomenclature and because initially it contains no objects, only later being populated with scattered comets.

Higuchi confirmed her predictions by cross-checking with numerical computations carried out in part on the PC Cluster at the Center for Computational Astrophysics of NAOJ. Comparing the analytical and computational results to the data for long-period comets listed in NASA's JPL Small Body Database showed that the distribution has two peaks, near the ecliptic and empty ecliptic as predicted. This is a strong indication that the formation models are correct and long-period comets formed on the ecliptic. However, Higuchi cautions, "The sharp peaks are not exactly at the ecliptic or empty ecliptic planes, but near them. An investigation of the distribution of observed small bodies has to include many factors. Detailed examination of the distribution of long-period comets will be our future work. The all-sky survey project known as the Legacy Survey of Space and Time (LSST) will provide valuable information for this study."

Were you aware that earthquakes are sometimes associated with luminescence, called earthquake lightning? This phenomenon had been documented throughout history, such as between 1965 and 1967, the Matsushiro earthquake swarm caused the surrounding mountain to flicker with light multiple times. In 1993 when an earthquake caused a tsunami off the coast in Southwest Hokkaido which caused 5 boats resting at shore to instantly ignite and burn. Various models have been proposed to explain earthquake lightnings, and it seems as though various factors contribute to such light emissions. Professor Emeritus Yuji Enomoto of Shinshu University, first author of the study Laboratory investigation of earthquake lightning due to landslide does not think these incidents can be explained in a unified way using a single model.

Therefore, the study focused on luminescence phenomenon caused by landslides. The team picked out various types of rock that form mountains representative of land across Japan; granite, pyroclastic rocks, rhyolite, limestone and serpentinite. What he found was that different rocks have different reasons for luminescence and some rocks such as serpentinite does not emit light at all.

Granite is known to exhibit remarkable photoemission due to the piezo-induced effect of the quartz within. There have been witness accounts of earthquake lightning in areas without granite. The researchers looked at descriptions of earthquake lightning in the Japan Historical Earthquake Archives. At least 5 of the 55 accounts of earthquake lightnings were due to landslides since 869 A.D.

You can probably imagine how light can be emitted when rocks collide violently. However, the luminescence of rocks is instantaneous and faint. For this reason, ultra-sensitive, high-speed, high resolution cameras and spectroscopes were required for the study. Fortunately, excellent cameras with an ISO sensitivity of 25,600 was available in the market at relatively low prices. For ultra-sensitive spectrum analysis, a device suitable for the purpose was commercially available but too expensive. Fortunately, the research team was able to borrow one from Konica Minolta, and the difficulty of continuing research was solved. Please view the attached video to see the method of the experiment, and different visual observations of the types of light emitted.

There are many cases in which electromagnetic anomalies associated with earthquakes have been documented while the cause remains a mystery. Even though it is a rare phenomenon, Professor Emeritus Enomoto feels an obligation as a Geo-tribologist to elucidate such phenomena. He hopes understanding such phenomena will lead to the advancement of earthquake prediction and promote active disaster prevention.

During the 2011 magnitude 9.0 Tohoku-Oki Earthquake, the number of electrons in the ionosphere suddenly increased above the epicenter of the earthquake about 10 minutes after the earthquake struck. Professor Emeritus Enomoto has studied this incident and proposed the lithosphere-hydrosphere-atmosphere-ionosphere coupling model in terms of current generation of charged mists. He is currently working to elucidate why in 1995, during the Hyogo-ken Nanbu Earthquake, the sky in the West which ordinarily remains dark became brighter than usual, and the color changed from bluish purple, white, then red. This is a difficult task. Professor Enomoto hopes to put together a research-outreach book that explains these incidents so that they can be understood by a wider audience.

RESEARCH TRIANGLE PARK, N.C. -- An Army-funded landmark discovery at New York University could change the way researchers develop and use optical technologies, such as lasers, sensors and photonic circuits over the next decade.

After years of research, the team of scientists achieved what many thought was perhaps impossible-they developed a method to create colloids that crystallize into the diamond lattice. This photonic technique, published in Nature, could lead to cheap, reliable and scalable fabrication of 3D photonic crystals for optical circuits and light filters.

These 3D photonic crystals--self-assembled formations of miniscule materials in a stable assembly--could open the door to lightweight high-efficiency lasers, precise light control with 3D photonic circuits and new materials for managing thermal or radio signatures.

High-efficiency lasers are key to Army modernization priorities, including Air and Missile Defense, as they play a key role in both precision sensing and directed energy systems. Likewise, efficient lasers and integrated photonic circuits will play a key role in next-generation technologies like light-based quantum computing, atomic clocks and gyroscopes for precision navigation and timing, and optical systems with improved size, weight, and power.

"This long-sought demonstration of the first self-assembled colloidal diamond lattices will unlock new research and development opportunities for important Department of Defense technologies which could benefit from 3D photonic crystals," said Dr. Evan Runnerstrom, program manager, Army Research Office, an element of the U.S. Army Combat Capabilities Development Command's Army Research Laboratory.

Colloidal crystals, made up of spheres hundreds of times smaller than the diameter of a human hair, can be arranged in different crystalline shapes depending on how the spheres are linked to one another. Each colloid attaches to another using strands of DNA glued to surfaces of the colloids that function as a kind of molecular Velcro. When colloids collide with each other in a liquid bath, the DNA snags and the colloids are linked. Depending on where the DNA is attached to the colloid, they can be programmed to spontaneously create complex structures.

This process has been used in the past to create strings of colloids and even close-packed cubic colloidal crystals, but not the diamond structure--which displays an optical band gap for visible light. Much as a semiconductor filters out electrons in a circuit, an optical band gap completely rejects certain wavelengths of light. Filtering light in this way is practical only if the colloids are arranged in a diamond formation, a process previously deemed too difficult and expensive to perform at commercial scale.

"There's been a great desire among engineers to make a diamond structure," said Dr. David Pine, professor of chemical and biomolecular engineering at the NYU Tandon School of Engineering. "Most researchers had given up on it, to tell you the truth - we may be the only group in the world who is still working on this. I think the publication of the paper will come as something of a surprise to the community."

The investigators discovered that they could use a steric interlock mechanism that would spontaneously produce the necessary staggered bonds to make this structure possible. When these pyramidal colloids approached each other, they linked in the necessary orientation to generate a diamond formation. Rather than going through the painstaking and expensive process of building these structures through the use of top-down approaches like nanofabrication, this mechanism allows the colloids to structure themselves from the bottom-up without the need for outside interference. Furthermore, the diamond structures are stable, even when the liquid they form in is removed.

The team and their collaborators--including researchers from the Centre de Recherche Paul Pascal - CNRS, Pessac, France; and Sungkyunkwan University, Suwon, South Korea--are now focused on converting these colloidal diamonds into 3D photonic crystals that can be used in a practical setting. They are already creating materials using their new structures that can filter out optical wavelengths in order to prove their usefulness in future technologies.

"I am thrilled with this result because it wonderfully illustrates a central goal of ARO's materials design program -- to support high-risk, high-reward research that unlocks bottom-up routes to creating extraordinary materials that were previously impossible to make," Runnerstrom said.

Scientists often refer to the neutrino as the “ghost particle.” Neutrinos were one of the most abundant particles at the origin of the universe and remain so today. Fusion reactions in the sun produce vast armies of them, which pour down on the Earth every day. Trillions pass through our bodies every second, then fly through the Earth as though it were not there.

“While first postulated almost a century ago and first detected 65 years ago, neutrinos remain shrouded in mystery because of their reluctance to interact with matter,” said Alessandro Lovato, a nuclear physicist at the U.S. Department of Energy’s (DOE) Argonne National Laboratory.

“Our team came into the picture because these experiments require a very accurate model of the interactions of neutrinos with the detector nuclei over a large energy range.” — Noemi Rocco, postdoc, Argonne Physics division and Fermilab.

Lovato is a member of a research team from four national laboratories that has constructed a model to address one of the many mysteries about neutrinos — how they interact with atomic nuclei, complicated systems made of protons and neutrons (“nucleons”) bound together by the strong force. This knowledge is essential to unravel an even bigger mystery — why during their journey through space or matter neutrinos magically morph from one into another of three possible types or “flavors.” 

To study these oscillations, two sets of experiments have been undertaken at DOE’s Fermi National Accelerator Laboratory (MiniBooNE and NOvA). In these experiments, scientists generate an intense stream of neutrinos in a particle accelerator, then send them into particle detectors over a long period of time (MiniBooNE) or five hundred miles from the source (NOvA).

Knowing the original distribution of neutrino flavors, the experimentalists then gather data related to the interactions of the neutrinos with the atomic nuclei in the detectors. From that information, they can calculate any changes in the neutrino flavors over time or distance. In the case of the MiniBooNE and NOvA detectors, the nuclei are from the isotope carbon-12, which has six protons and six neutrons.

“Our team came into the picture because these experiments require a very accurate model of the interactions of neutrinos with the detector nuclei over a large energy range,” said Noemi Rocco, a postdoc in Argonne’s Physics division and Fermilab. Given the elusiveness of neutrinos, achieving a comprehensive description of these reactions is a formidable challenge.

The team’s nuclear physics model of neutrino interactions with a single nucleon and a pair of them is the most accurate so far. “Ours is the first approach to model these interactions at such a microscopic level,” said Rocco. “Earlier approaches were not so fine grained.”

One of the team’s important findings, based on calculations carried out on the now-retired Mira supercomputer at the Argonne Leadership Computing Facility (ALCF), was that the nucleon pair interaction is crucial to model neutrino interactions with nuclei accurately. The ALCF is a DOE Office of Science User Facility.

“The larger the nuclei in the detector, the greater the likelihood the neutrinos will interact with them,” said Lovato. “In the future, we plan to extend our model to data from bigger nuclei, namely, those of oxygen and argon, in support of experiments planned in Japan and the U.S.”

Rocco added that “For those calculations, we will rely on even more powerful ALCF computers, the existing Theta system and upcoming exascale machine, Aurora.”

Scientists hope that, eventually, a complete picture will emerge of flavor oscillations for both neutrinos and their antiparticles, called “antineutrinos.” That knowledge may shed light on why the universe is built from matter instead of antimatter — one of the fundamental questions about the universe.

The paper, titled &ldquoAb Initio Study of (ν,−) and (¯ν,+) Inclusive Scattering in 12C: Confronting the MiniBooNE and T2K CCQE Data,” is published in Physical Review X. Besides Rocco and Lovato, authors include J. Carlson (Los Alamos National Laboratory), S. Gandolfi (Los Alamos National Laboratory), and R. Schiavilla (Old Dominion University/Jefferson Lab).

Eight months after the space telescope CHEOPS started its journey into space, the first scientific publication using data from CHEOPS has been issued. CHEOPS is the first ESA mission dedicated to characterising known exoplanets. Exoplanets, i.e. planets outside the Solar system, were first found in 1995 by two Swiss astronomers, Michel Mayor and Didier Queloz, who were last year awarded the Nobel Prize for this discovery. CHEOPS was developed as part of a partnership between ESA and Switzerland. Under the leadership of the University of Bern and ESA, a consortium of more than a hundred scientists and engineers from eleven European states was involved in constructing the satellite over five years. The Science Operations Center of CHEOPS is located at the observatory of the University of Geneva.

Using data from CHEOPS, scientists have recently carried out a detailed study of the exoplanet WASP-189b. The results have just been accepted for publication in the journal Astronomy & Astrophysics. Willy Benz, professor of astrophysics at the University of Bern and head of the CHEOPS consortium, was delighted about the findings: "These observations demonstrate that CHEOPS fully meets the high expectations regarding its performance."

One of the most extreme planets in the universe

WASP-189b, the target of the CHEOPS observations, is an exoplanet orbiting the star HD 133112, one of the hottest stars known to have a planetary system. "The WASP-189 system is 322 light years away and located in the constellation Libra (the weighing scales)," explains Monika Lendl, lead author of the study from the University of Geneva, and member of the National Centre of Competence in Research PlanetS.

"WASP-189b is especially interesting because it is a gas giant that orbits very close to its host star. It takes less than 3 days for it to circle its star, and it is 20 times closer to it than Earth is to the Sun," Monika Lendl describes the planet, which is more than one and a half times as large as Jupiter, the largest planet of the Solar system.

Monika Lendl further explains that planetary objects like WASP-189b are very exotic: "They have a permanent day side, which is always exposed to the light of the star, and, accordingly, a permanent night side." This means that its climate is completely different from that of the gas giants Jupiter and Saturn in our solar system. "Based on the observations using CHEOPS, we estimate the temperature of WASP-189b to be 3,200 degrees Celsius. Planets like WASP-189b are called "ultra-hot Jupiters". Iron melts at such a high temperature, and even becomes gaseous. This object is one of the most extreme planets we know so far," says Lendl.

Highly precise brightness measurements

"We cannot see the planet itself as it is too far away and too close to its host star, so we have to rely on indirect methods," explains Lendl. For this, CHEOPS uses highly precise brightness measurements: When a planet passes in front of its star as seen from Earth, the star seems fainter for a short time. This phenomenon is called a transit. Monika Lendl explains: "Because the exoplanet WASP-189b is so close to its star, its dayside is so bright that we can even measure the 'missing' light when the planet passes behind its star; this is called an occultation. We have observed several such occultations of WASP-189b with CHEOPS," says Lendl. "It appears that the planet does not reflect a lot of starlight. Instead, most of the starlight gets absorbed by the planet, heating it up and making it shine." The researchers believe that the planet is not very reflective because there are no clouds present on its dayside: "This is not surprising, as theoretical models tell us that clouds cannot form at such high temperatures."

And the star is special too

"We also found that the transit of the gas giant in front of its star is asymmetrical. This happens when the star possesses brighter and darker zones on its surface," adds Willy Benz. "Thanks to CHEOPS data, we can conclude that the star itself rotates so quickly that its shape is no longer spherical; but ellipsoidal. The star is being pulled outwards at its equator." continues Benz.

The star around which WASP-189b orbits is very different from the sun. Monika Lendl says: "The star is considerably larger and more than two thousand degrees Celsius hotter than our sun. Because it is so hot, the star appears blue and not yellow-white like the sun." Willy Benz adds: "Only a handful of planets are known to orbit such hot stars, and this system is the brightest by far." As a consequence, it forms a benchmark for further studies.

In conclusion, Willy Benz explains: "We are expecting further spectacular findings on exoplanets thanks to observations with CHEOPS. The next papers are already in preparation."

Researchers at Lund University in Sweden have developed a computational model which is effective in detecting and identifying genetic mutations in breast tumours. The study, the largest of its kind in the world, includes results from over 3 200 patients with breast cancer.

The researchers used RNA sequencing, a sensitive, precise tool which has very gradually started to be applied clinically, although not yet for breast cancer. The study, published in the scientific journal EMBO Molecular Medicine, used breast tumours for analysis from the unique Swedish SCAN-B project. Since it was initiated over 10 years ago, across a wide geography of Sweden SCAN-B has enrolled over 15 000 patients with breast cancer thus far, and around 100 additional patients are included every month.

"We hope that SCAN-B RNA sequencing will be in clinical use as early as next year, mainly to help in the identification of which breast tumours are high-risk and which are low-risk. The aim is for the patient to know, already a week after surgery to remove the tumour, which personalised treatment is best suited to the individual", says Lao Saal, one of the researchers who led the study.

When the Lund team analysed the genetic mutations in the breast tumours of the patients in the study, they found that almost 87 per cent had at least one mutation for which potential drugs already exist.

"When we followed the patterns of mutations in the tumours and related them to patient outcomes, we observed that 34 per cent of them had a mutation in a specific gene, PIK3CA, and that in general these patients had a good prognosis. In 3 per cent of the patients we found mutations in another gene, ERBB2, which was associated with a worse prognosis", says Lao Saal.

"The results of the study add another dimension to how RNA sequencing can be used as a potential future 'clinical tool', as we showed that breast cancer RNA sequencing not only gives a readout of the patterns of genes being highly or lowly expressed, but also works to detect and identify gene mutations in breast cancer tumours. We are therefore convinced that the technique would be helpful in improving prognosis and treatment for patients."

In the same study, doctoral student and first author Christian Brueffer also developed a web database and interactive software through which other researchers can access the results for their own studies.

"Of course we want scientific progress to happen as quickly as possible, which is why we have made the database accessible to other researchers as well", says Lao Saal.

Worcester, Mass. - Sept. 23, 2020 - Using a limited set of mathematical equations, Worcester Polytechnic Institute mathematical sciences professor Mayer Humi said he has confirmed a 224-year-old math conjecture about the origins of our solar system, providing insights about the process that leads to the formation of solar systems across the universe.

"The science community is aware by now that there are thousands of solar systems in the galaxy. But what is not known is how these solar systems came into existence," said Humi. "And what I've done is show that the first step to the creation of a solar system is the emergence of rings around a protostar. So from that standpoint, I've been able to verify a conjecture that is more than two centuries old."

Humi's peer-reviewed paper on the topic, titled "On the Evolution of a Primordial Interstellar Gas Cloud," was recently published in the Journal of Mathematical Physics and was designated an "editor's pick" as a featured piece.

Humi, a mathematical physicist working on the development and application of mathematical methods to astrophysics, atmospheric research, and satellite orbits, has been studying this question for more than 20 years. It is a mystery that has fascinated many generations of scientists, and an inquiry that became more pertinent as observations confirmed that solar systems and exoplanets are abundant in our galaxy. A conjecture, Humi noted, is a mathematical statement that has not been proven.

"We want to know how our solar system will evolve as time goes by," said Humi. "There are two theories: one conjecture is that all the planets will be absorbed by the sun. The other conjecture is that planets are running away from the sun.

The fundamental question is: How stable is the solar system? Are we going to be absorbed by the sun or are we going to run away from the sun?"

Humi says this research also has implications for issues such as climate change and the environment. "Imagine if we are going to come a few million miles closer to the sun. That would lead to major changes in climate and impact humanity. Oceans might evaporate."

In 1796, the French mathematical physicist Pierre-Simon Laplace conjectured that the first step for the formation of a solar system from a primordial celestial cloud of gas requires the creation of rings of condensed matter within a cloud.

Even with its intuitively appealing contents, Humi said, this conjecture remained unverified for more than two centuries despite many efforts. Until now.

Humi was able to use a time-dependent model (based on Euler-Poisson equations) for the evolution of a primordial gas cloud and confirmed--for what Humi believes is the first time--that, under proper conditions, Laplace's conjecture is correct.

Humi said there were some challenges with his research.

"The real stumbling block that I had to overcome in order to obtain this result was to be able to reduce the complexity of the original model," he said. "That model has six nonlinear partial differential equations, which I reduced to three. I then provided analytical solutions to these equations, which demonstrated the creation matter rings as conjectured by Laplace."

Humi noted that there has been a surge of interest in Laplace's conjecture in recent years due to the actual discovery of ring structures around the star HL Tau in the constellation Taurus.

Humi said his research is distinctive because it makes us consider our own existence.

"It relates to the age-old question about humanity, our place in the universe, and our destiny," he said.

New insight on how people with retinal degenerative disease can maintain their night vision for a relatively long period of time has been published today in the open-access eLife journal.

The study in mice suggests that second-order neurons in the retina, which relay visual signals to the retinal ganglion cells that project into the brain, maintain their activity in response to photoreceptor degeneration to resist visual decline - a process known as homeostatic plasticity. Rod photoreceptors are the cells responsible for the most sensitive aspects of our vision, allowing us to see at night, but can be lost during retinal degenerative disease.

The new findings pave the way for further research to understand how our eyes and other sensory systems respond and adapt to potentially compromising changes throughout life.

"Neuronal plasticity of the inner retina has previously been seen to occur in response to photoreceptor degeneration, but this process has been mostly considered maladaptive rather than homeostatic in nature," explains co-first author Henri Leinonen, a postdoctoral researcher at the University of California, Irvine, US. "Our study was conducted at a relatively early stage of disease progression, while most previous studies focused on severe disease stages, which may account for the discrepancy. Very recently, several studies using triggered photoreceptor loss models have shown adaptive responses in bipolar cells - cells that connect the outer and inner retina. But whether such adaptation occurs during progressive photoreceptor degenerative disease, and whether it helps to maintain visual behaviour, was unknown."

To address this question, Leinonen and colleagues studied a mouse model of retinitis pigmentosa. This is the name given to a group of related genetic disorders caused by the P23H mutation in rhodopsin, a protein that enables us to see in low-light conditions. Retinitis pigmentosa causes the breakdown and loss of rod-shaped photoreceptor cells in the retina, leading to difficulties seeing at night.

The team combined whole-retinal RNA-sequencing, electrophysiology and behavioral experiments in both healthy mice and those with retinitis pigmentosa as the disease progressed. Their experiments showed that the degeneration of rod photoreceptors triggers genomic changes that involve robust compensatory molecular changes in the retina and increases in electrical signalling between rod photoreceptors and rod bipolar cells. These changes were associated with well-maintained behavioural night vision despite the loss of over half of the rod photoreceptor cells in mice with retinitis pigmentosa.

"This mechanism may explain why patients with inherited retinal diseases can maintain their normal vision until the disease reaches a relatively advanced state," says co-first author Nguyen Pham, Graduate Research Assistant at the John A. Moran Eye Center, University of Utah Health, Salt Lake City, US. "It could also inspire novel treatment strategies for diseases that lead to blindness."

"Our results suggest retinal adaptation as the driver of persistent visual function during photoreceptor degenerative disease," concludes senior author Frans Vinberg, PhD, Assistant Professor at the John A. Moran Eye Center, University of Utah Health. "Additional research is now needed to discover the exact homeostatic plasticity mechanisms that promote cellular signalling and visual function. This could help inform the development of potential new interventions to enhance homeostatic plasticity when needed."

Solar flares are violent explosions on the sun that fling out high-energy charged particles, sometimes toward Earth, where they disrupt communications and endanger satellites and astronauts.

But as scientists discovered in 1996, flares can also create seismic activity -- sunquakes -- releasing impulsive acoustic waves that penetrate deep into the sun's interior.

While the relationship between solar flares and sunquakes is still a mystery, new findings suggest that these "acoustic transients" -- and the surface ripples they generate -- can tell us a lot about flares and may someday help us forecast their size and severity.

A team of physicists from the United States, Colombia and Australia has found that part of the acoustic energy released from a flare in 2011 emanated from about 1,000 kilometers beneath the solar surface -- the photosphere -- and, thus, far beneath the solar flare that triggered the quake.

The results, published Sept. 21 in The Astrophysical Journal Letters, come from a diagnostic technique called helioseismic holography, introduced in the late 1900s by French scientist Françoise Roddier and extensively developed by U.S. scientists Charles Lindsey and Douglas Braun, now at NorthWest Research Associates in Boulder, Colorado, and co-authors of the paper.

Helioseismic holography allows scientists to analyze acoustic waves triggered by flares to probe their sources, much as seismic waves from megaquakes on Earth allow seismologists to locate their epicenters. The technique was first applied to acoustic transients released from flares by a graduate student in Romania, Alina-Catalina Donea, under the supervision of Lindsey and Braun. Donea is now at Monash University in Melbourne, Australia.

"It's the first helioseismic diagnostic specifically designed to directly discriminate the depths of the sources it reconstructs, as well as their horizontal locations," Braun said.

"We can't see the sun's inside directly. It is opaque to the photons that show us the sun's outer atmosphere, from where they can escape to reach our telescopes," said co-author Juan Camilo Buitrago-Casas, a University of California, Berkeley, doctoral student in physics from Colombia. "The way we can know what happens inside of the sun is via seismic waves that make ripples on the solar surface similar to those caused by earthquakes on our planet. A big explosion, such as a flare, can inject a powerful acoustic pulse into the sun, whose subsequent signature we can use to map its source in some detail. The big message of this paper is that the source of at least some of this noise is deeply submerged. We are reporting the deepest source of acoustic waves so far known in the sun."

How sunquakes produce ripples on the sun's surface

The acoustic explosions that cause sunquakes in some flares radiate acoustic waves in all directions, primarily downward. As the downward-traveling waves move through regions of ever-increasing temperature, their paths are bent by refraction, ultimately heading back up to the surface, where they create ripples like those seen after throwing a pebble in a pond. The time between the explosion and the arrival of the ripples is about 20 minutes.

"The ripples, then, are not just a surface phenomenon, but the surface signature of waves that have gone deep beneath the active region and then back up to the outlying surface in the succeeding hour," Lindsey said. Analyzing the surface ripples can pinpoint the source of the explosion.

"It has been widely supposed that the waves released by acoustically active flares are injected into the solar interior from above. What we are finding is the strong indication that some of the source is far beneath the photosphere," said Juan Carlos Martínez Oliveros, a solar physics researcher at UC Berkeley's Space Sciences Laboratory and a native of Colombia. "It seems like the flares are the precursor, or trigger, of the acoustic transient released. There is something else happening inside the sun that is generating at least some part of the seismic waves."

"Using an analogy from medicine, what we (solar physicists) were doing before is like using X-rays to look at one snapshot of the interior of the sun. Now, we are trying to do a CAT scan, to view the solar interior in three dimensions," added Martínez Oliveros.

The Colombians, including students Ángel Martínez and Valeria Quintero Ortega at Universidad Nacional de Colombia, in Bogotá, are co-authors of the ApJ Letters paper with their supervisor, Benjamín Calvo-Mozo, associate professor of astronomy.

"We have known about acoustic waves from flares for a little over 20 years now, and we have been imaging their sources horizontally since that time. But we have only recently discovered that some of those sources are submerged below the solar surface," said Lindsey. "This may help explain a great mystery: Some of these acoustic waves have emanated from locations that are devoid of local surface disturbances that we can directly see in electromagnetic radiation. We have wondered for a long time how this can happen."

A seismically active sun

For more than 50 years, astronomers have known that the sun reverberates with seismic waves, much like the Earth and its steady hum of seismic activity. This activity, which can be detected by the Doppler shift of light emanating from the surface, is understood to be driven by convective storms that form a patchwork of granules about the size of Texas, covering the sun's surface and continually rumbling.

Amid this background noise, magnetic regions can set off violent explosions releasing waves that make the spectacular ripples that then appear on the sun's surface in the succeeding hour, as discovered 24 years ago by astronomers Valentina Zharkova and Alexander Kosovichev.

As more sunquakes have been discovered, flare seismology has blossomed, as have the techniques to explore their mechanics and their possible relationship to the architecture of magnetic flux underlying active regions.

Among the open questions: Which flares do and don't produce sunquakes? Can sunquakes occur without a flare? Why do sunquakes emanate primarily from the edges of sunspots, or penumbrae? Do the weakest flares produce quakes? What is the lower limit?

Until now, most solar flares have been studied as one-offs, since strong flares, even during times of maximum solar activity, may occur only a few times a year. The initial focus was on the largest, or X-class, flares, classified by the intensity of the soft X-rays they emit. Buitrago-Casas, who obtained his bachelor's and master's degrees from Universidad Nacional de Colombia, teamed up with Lindsey and Martínez Oliveros to conduct a systematic survey of relatively weak solar flares to increase their database, for a better understanding of the mechanics of sunquakes.

Of the 75 flares captured between 2010 and 2015 by the RHESSI satellite -- a NASA X-ray satellite designed, built and operated by the Space Sciences Laboratory and retired in 2018 -- 18 produced sunquakes. One of Buitrago-Casas's acoustic transients, the one released by the flare of July 30, 2011, caught the eyes of undergraduate students Martínez, now a graduate student, and Quintero Ortega.

"We gave our student collaborators at the National University the list of flares from our survey. They were the first ones who said, 'Look at this one. It's different! What happened here?'" Buitrago-Casas said. "And so, we found out. It was super exciting!"

Martínez and Quintero Ortega are the first authors on a paper describing the extreme impulsivity of the waves released by that flare of July 30, 2011, that appeared in the May 20, 2020, issue of The Astrophysical Journal Letters. These waves had spectral components that gave the researchers unprecedented spatial resolution of their source distributions.

Thanks to superb data from NASA's Solar Dynamics Observatory satellite, the team was able to pinpoint the source of the explosion that generated the seismic waves 1,000 kilometers below the photosphere. This is shallow, relative to the sun's radius of nearly 700,000 kilometers, but deeper than any previously known acoustic source in the sun.

A source submerged below the sun's photosphere with its own morphology and no conspicuous directly overlying disturbance in the outer atmosphere suggests that the mechanism that drives the acoustic transient is itself submerged.

"It may work by triggering a compact explosion with its own energy source, like a remotely triggered earthquake," Lindsey said. "The flare above shakes something beneath the surface, and then a very compact unit of submerged energy gets released as acoustic sound," he said. "There is no doubt that the flare is involved, it's just that the existence of this deep compact source suggests the possibility of a separate, distinctive, compact, submerged energy source driving the emission."

About half of the medium-sized solar flares that Buitrago-Casas and Martínez Oliveros have catalogued have been associated with sunquakes, showing that they commonly occur together. The team has since found other submerged sources associated with even weaker flares.

The discovery of submerged acoustic sources opens the question of whether there are instances of acoustic transients being released spontaneously, with no surface disturbance, or no flare, at all.

"If sunquakes can be generated spontaneously in the sun, this might lead us to a forecasting tool, if the transient can come from magnetic flux that has yet to break the sun's surface," Martínez Oliveros said. "We could then anticipate the inevitable subsequent emergence of that magnetic flux. We may even forecast some details about how large an active region is about to appear and what type -- even, possibly, what kinds of flares -- it might produce. This is a long shot, but well worth looking into."

When most people think of fungi, the thoughts are usually not good, turning to something that does damage more than those that are actually helpful.

Yet, fungi play a critical role in the growth and development of plant life and have for millions of years. Scientists have known for a long time that arbuscular mycorrhizal (AM) fungi that live in harmony with about 90% of land plants and play a key role in their root systems, are responsible for carrying needed phosphate to plants to help growth.

Now, however, thanks to a discovery by a team of scientists from Texas Tech University's Institute of Genomics for Crop Abiotic Stress Tolerance (IGCAST) in the Department of Plaint and Soil Science, and the Nanjing Agricultural University's State Key Laboratory of crop Genetics and Germplasm Enhancement, that symbiotic role may go even further.

That research team, which included professor Guohua Xu, Prof. Aiqun Chen and Dr. Huimin Feng from Nanjing Agricultural University and, Luis Herrera-Estrella, the President's Distinguished Professor of Plant Genomics and director of IGCAST, and assistant professor Damar López-Arredondo, discovered that AM fungi also acted as a supplier of nitrogen to the plant, the protein (NPF4.5) responsible for transporting nitrates from the fungi to the plant, and that this symbiotic nitrate pathway and the function of the protein are present in crops such as rice, and probably most other plant species.

The results from the paper, "Functional analysis of the OsNPF4.5 nitrate transporter reveals a conserved mycorrhizal pathway of nitrogen acquisition in plants," were recently published by Proceedings of the National Academy of Sciences (PNAS) of the U.S.

Xu highlighted their finding that the fungi colonization efficiency, promotion of plant growth and nutrient uptake were maintained and even enhanced at high nitrogen supply levels, which is opposite to the high phosphate suppressed colonization, indicating the general contribution of mycorrhizal route to improving N use efficiency at varied N presence.

This discovery could lead to groundbreaking agricultural practices that allow for a reduction in the amount of nitrogen fertilizer required for crop production, which will help reduce production costs and benefit the environment by reducing agrochemical use.

"In our study, we showed the nitrate transporter is contained in many plant species and that it is activated by the mycorrhizal association in maize, sorghum and several other plant species," Herrera-Estrella said. "Based on our data, we propose that nitrate transport takes place in many if not most plant species, and that the protein plays a key role in the process."

Hundreds of millions of years ago, when plants moved from aquatic origins and began taking over land masses, their lack of a strong root system became a hinderance in obtaining water and nutrients. Herrera-Estrella said fossilized evidence showed that, early in in the evolutionary process, land plants developed the relationship with mycorrhizal fungi, which helped improve the fitness of host plants by facilitating mineral nutrition and water absorption and by increasing tolerance to biotic and abiotic stresses.

Herrera-Estrella pointed out, though, that past research has discovered that the symbiotic relationship between plants and AM fungi is most active in soil with low phosphate availability and suppressed in soil with high levels of available nutrients. That means cultivated crops that are highly fertilized see a severely reduced or completely suppressed impact from mycorrhiza.

The goal of the research was to determine whether mycorrhiza could provide other nutrients such as nitrogen to the plant. Indirect evidence has shown the fungi could supply the plant with ammonium (NH4+) as a nitrogen source, but that it is quickly converted into nitrate (NO3-) by the microbes in the aerobic soil. That means that under most soil conditions, nitrate is the dominant form of N supplied to the plant.

In order to test for nitrate transfer ability, the researchers used nitrogen isotopes to determine the capacity of the fungi to take nitrate ad deliver it to the plant for intake. Researchers also identified the gene (NPF4.5) specifically activated in rice roots when joined by mycorrhizal fungi and were able to identify the role of this gene in nitrate delivery by producing rice mutants that did not have this transporting gene.

"We found that when the gene is inactivated, the amount of nitrate that the plant can get from the fungi is drastically reduced," Dr. Chen said. "Thus, we functionally confirmed that NPF4.5 was the important protein in the transport of nitrogen from the fungi to the plant. We also used plant transformation to generate the rice plants that enrich NPF4.5 proteins in the absence of the mycorrhiza. We found that these transgenic plants can produce more biomass and show higher nitrogen uptake efficiency than normal plants when grown in nitrate contained medium, which has a great potential for use in agriculture."

Researchers estimate that rice containing the mycorrhizal relationship between plant and fungi could receive more than 40% of its nitrogen due to the mycorrhizal pathway and that the specific nitrate transporter gene, NPF4.5, accounted for approximately 45% of the mycorrhizal nitrate uptake.

López-Arredondo said the next steps in the project will be to test the transgenic plants under field conditions and deeply understand the mechanisms that specifically activate the NPF4.5 nitrate transporter gene when the plant joins with the fungi, as well as discovering the chemical signals the fungi send to the plant to specifically activate this and other nutrient transporter genes probably required for this interaction.

Herrera-Estrella, an Emeritus Professor of Cinvestav in Mexico and member of the US National Academy of Sciences stated "This is an interesting and productive collaboration between Texas Tech and the Nanjing Agricultural University," "This type of international collaboration can rally boost the advancement of science."