Mexico's Yucatan Peninsula reveals a cryptic methane-fueled ecosystem in flooded caves

Caves within a karst subterranean estuary are filled with separated fresh (green), brackish (gray) and saline (blue) waters. Within the subterranean estuary, methane (CH4) and other forms of dissolved organic carbon (DOC) created during the decomposition of soil from the overlying tropical forest sustain a complex cave-adapted ecosystem.

In the underground rivers and flooded caves of Mexico's Yucatan Peninsula, where Mayan lore described a fantastical underworld, scientists have found a cryptic world in its own right. Here, methane and the bacteria that feed off it form the lynchpin of an ecosystem that is similar to what has been found in deep ocean cold seeps and some lakes, according to recent research by Texas A&M University at Galveston, the U.S. Geological Survey and a team of collaborators from Mexico, The Netherlands, Switzerland and other U.S. institutions.

The research, conducted by scientists who are trained in cave diving in addition to their other expertise, is the most detailed ecological study ever for a coastal cave ecosystem that is always underwater. In fact, the scientists had to use techniques that had previously been used by deep-sea submergence vehicles to be able to study the environment.

"The opportunity to work with an international team of experts has been a remarkable experience for me," said David Brankovits, who is the paper's lead author and conducted the research during his Ph.D. studies at TAMUG. "Finding that methane and other forms of mostly invisible dissolved organic matter are the foundation of the food web in these caves explains why cave-adapted animals are able to thrive in the water column in a habitat without visible evidence of food."

The study was conducted in the Ox Bel Ha cave network of the northeastern Yucatan, which is described as a subterranean estuary because the flooded cave passages contain distinct water layers consisting of freshwater fed by rainfall and salt water from the coastal ocean. This subterranean estuary complex covers an area approximately the size of Galveston Bay, the seventh largest surface estuary in the United States.

The freshwater portion of the caves and the sinkholes, which are used to access the caves and are referred to locally as cenotes, are important sources of freshwater for communities throughout the Yucatan. Methane in the caves forms naturally beneath the jungle floor and migrates downward, deeper into the water and caves. Normally, all of the methane formed in soils migrates upward, towards the atmosphere.

This sets the stage for the bacteria and other microbes that form the basis for the cave ecosystem. The microbes eat both the methane in the water and other dissolved organic material that the freshwater brought with it from the surface. The microbes then fuel a food web that is dominated by crustaceans, including a cave-adapted shrimp species that obtains about 21 percent of its nutrition from methane.

"The processes we are investigating in these stratified groundwater systems are analogous to what is happening in the global ocean, especially in oxygen minimum zones where deoxygenation is a growing concern," says John Pohlman, a coauthor of the study and a USGS biogeochemist whose work from the early 90s motivated the research. "Although accessing these systems requires specialized training and strict adherence to cave diving safety protocols, relative to the complexity of an oceanographic expedition, the field programs we organize are simple and economical."

One surprising finding was how important the dissolved organic material like methane was to the caves' food web. Prior studies had assumed that the majority of organic material that feeds the microbes of caves came from vegetation and other detritus in the tropical forest that washed into the caves from the cenotes.

However, deep within the caves, where the study was conducted, there is very little of that surface debris, so the microbes depend on methane and the other dissolved organics percolating downward through the ceiling of the caves.

Read more at Science Daily

A horse is a horse, of course, of course -- except when it isn't

Two skulls of the new genus Haringtonhippus from Nevada (upper) and Texas (lower).

An international team of researchers has discovered a previously unrecognized genus of extinct horses that roamed North America during the last ice age.

The new findings, published November 28 in the journal eLife, are based on an analysis of ancient DNA from fossils of the enigmatic "New World stilt-legged horse" excavated from sites such as Natural Trap Cave in Wyoming, Gypsum Cave in Nevada, and the Klondike goldfields of Canada's Yukon Territory.

Prior to this study, these thin-limbed, lightly built horses were thought to be related to the Asiatic wild ass or onager, or simply a separate species within the genus Equus, which includes living horses, asses, and zebras. The new results, however, reveal that these horses were not closely related to any living population of horses.

Now named Haringtonhippus francisci, this extinct species of North American horse appears to have diverged from the main trunk of the family tree leading to Equus some 4 to 6 million years ago.

"The horse family, thanks to its rich and deep fossil record, has been a model system for understanding and teaching evolution. Now ancient DNA has rewritten the evolutionary history of this iconic group," said first author Peter Heintzman, who led the study as a postdoctoral researcher at UC Santa Cruz.

"The evolutionary distance between the extinct stilt-legged horses and all living horses took us by surprise, but it presented us with an exciting opportunity to name a new genus of horse," said senior author Beth Shapiro, professor of ecology and evolutionary biology at UC Santa Cruz.

The team named the new horse after Richard Harington, emeritus curator of Quaternary Paleontology at the Canadian Museum of Nature in Ottawa. Harington, who was not involved in the study, spent his career studying the ice age fossils of Canada's North and first described the stilt-legged horses in the early 1970s.

"I had been curious for many years concerning the identity of two horse metatarsal bones I collected, one from Klondike, Yukon, and the other from Lost Chicken Creek, Alaska. They looked like those of modern Asiatic kiangs, but thanks to the research of my esteemed colleagues they are now known to belong to a new genus," said Harington. "I am delighted to have this new genus named after me. "

The new findings show that Haringtonhippus francisci was a widespread and successful species throughout much of North America, living alongside populations of Equus but not interbreeding with them. In Canada's North, Haringtonhippus survived until roughly 17,000 years ago, more than 19,000 years later than previously known from this region.

At the end of the last ice age, both horse groups became extinct in North America, along with other large animals like woolly mammoths and saber-toothed cats. Although Equus survived in Eurasia after the last ice age, eventually leading to domestic horses, the stilt-legged Haringtonhippus was an evolutionary dead end.

"We are very pleased to name this new horse genus after our friend and colleague Dick Harington. There is no other scientist who has had greater impact in the field of ice age paleontology in Canada than Dick," said coauthor Grant Zazula, a Government of Yukon paleontologist. "Our research on fossils such as these horses would not be possible without Dick's life-long dedication to working closely with the Klondike gold miners and local First Nations communities in Canada's North."

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How Himalayan rivers influenced ancient Indus civilization settlements

Remnant of a street in the urban centre of Kalibangan. The Ghaggar-Hakra palaeochannel can be seen in the distance.

The Indus or Harappan Civilisation was a Bronze Age society that developed mainly in the northwestern regions of South Asia from 5300 to 3300 years ago, at about the same time as urban civilisations developed in Mesopotamia and Egypt. Archaeological evidence shows that many of the settlements in the Indus Civilisation developed along the banks of a river called the Ghaggar-Hakra in northwest India and Pakistan.

It has generally been thought that this was a major Himalayan river that dried up either due to climatic or tectonic changes. However, until now, scientists had not pinpointed how long ago the river dried up, and had assumed that it flowed while the Indus urban centres grew, playing an active role in their development.

A new study, led by researchers from Imperial College London and the Indian Institute of Technology Kanpur, has now provided evidence that a major Himalayan river did not flow at the same time as the development of Indus Civilisation urban settlements. This research shows how ancient urban centres didn't necessarily need an active, flowing river system in order to thrive.

Professor Sanjeev Gupta, lead author from Department of Earth Science and Engineering at Imperial, said: "The findings challenge our current understanding of how urbanisation in many ancient civilisations began and grew in relation to natural resources. Contrary to current belief, it was the departure of a large river, rather than its arrival, that triggered the growth of Indus urban centres."

Today's study, published in the journal Nature Communications, shows that a major Himalayan river, the Sutlej River, used to flow along the trace of the Ghaggar-Hakra river but rapidly changed course upstream eight thousand years ago. This meant that three thousand years later, when the Indus people settled the area, there was only an abandoned large river valley occupied by seasonal monsoon river flow instead of a large Himalayan river.

The researchers say the time gap between the river shifting course and the Indus Civilisation settlements appearing rules out the existence of a Himalayan-fed river that nourished Indus Civilisation urban settlements along the river channel.

The team were also able to pinpoint what the original source of the river sediments had been, showing that the Himalayan Sutlej River had once flowed along the Ghaggar-Hakra dried river channel, or palaeochannel.

They found that after the Sutlej River changed course, the scar it left in the landscape acted as a topographic low to capture river flow during the monsoon. This meant that despite not living along a permanent river, the Indus settlements still benefited from a water source.

Professor Rajiv Sinha, co-author from the Indian Institute of Technology Kanpur, said: "We now know that, given the right conditions, valleys that have lost their rivers can still serve as a water source. The civilization would also not have been threatened by the risk of devastating floods that living next to a big river brings."

To determine the timing of the river, the team drilled cores through the dried Ghaggar-Hakra river bed and analysed the layers of river sediments that had built up over time. To find out when the sediments had been deposited by the river while it was flowing, they dated mineral grains extracted from the sediment, which was carried out at the DTU-Aarhus Risø laboratory in Denmark.

When sediments are buried beneath the ground, natural background radiation results in energy being stored in mineral grains such as quartz and feldspar. If the mineral grains are not exposed to light the amount of energy builds up and represents the amount of time since their burial.

Scientists can then measure the stored energy in the laboratory and pinpoint when the layers of sediment were buried. This method, called optically stimulated luminescence dating, can therefore tell them when the river last flowed.

The team were also able to determine where the original material in the river came from by dating mineral grains such as zircon and mica, revealing the previous course of the river.

Read more at Science Daily

Unique metal artifacts from Iron Age settlement shed new light on prehistoric feasting

Caption This is a copper alloy horn-cap ULAS.

A unique collection of Iron Age metal artefacts which sheds new light on feasting rituals among prehistoric communities has been discovered by archaeologists from the University of Leicester during an excavation at Glenfield Park, Leicestershire.

The team, from the University of Leicester Archaeological Services (ULAS), has located a trove of ancient treasures at the site, including eleven complete, or near complete, Iron Age cauldrons, fine ring-headed dress pins, an involuted brooch and a cast copper alloy object known as a 'horn-cap', which may have been part of a ceremonial staff, emphasising the unusual nature of the metalwork assemblage.

The collection is unprecedented in terms of the overall mix of findings, with the cauldrons highlighting the role of the settlement as a potential host site for feasting, with associated traditions of ritual deposition of important objects.

The project took place over the winter of 2013/14 and was commissioned in advance of Glenfield Park, a large-scale warehouse and distribution development by Wilson Bowden Developments Ltd. close to the M1, and between the villages of Glenfield and Kirby Muxloe, both situated on the urban fringes of Leicester.

The excavation has revealed evidence for long-term landscape inhabitation throughout most of the Iron Age and Roman periods, across an area of c. 12ha, with the main focus being a dense c. 4ha spread of settlement remains comprising many roundhouses, enclosures, 4-post structures and pits that occupied the southern slopes of a low spur of slightly higher ground at the northern end of the development area.

The cauldrons and other finds at Glenfield Park are the result of a series of events that took place over a considerable length of time and have resulted in multiple episodes of deposition across the settlement.

These repeated acts mark the site out as a potential ritual and ceremonial centre that also hosted large feasts.

John Thomas, director of the excavation and Project Officer from the University of Leicester Archaeological Services, said: "Glenfield Park is an exceptional archaeological site, with a fantastic array of finds that highlight this as one of the more important discoveries of recent years. Early occupation of the site during the earlier middle Iron Age (5th -- 4th centuries BC) was relatively modest, consisting of a small open settlement that occupied the south-facing, lower slopes of the spur. Slightly later in the middle Iron Age, indicated to be in the 4th or 3rd centuries BC by radiocarbon dating, the settlement underwent striking changes in character. Individual roundhouses were now enclosed, there was far more evidence for material culture, and rituals associated with the settlement involved apparently deliberate burial of a striking assemblage of metalwork.

"It is the metalwork assemblage that really sets this settlement apart. The quantity and quality of the finds far outshines most of the other contemporary assemblages from the area, and its composition is almost unparalleled. The cauldron assemblage in particular makes this a nationally important discovery.

"They represent the most northerly discovery of such objects on mainland Britain and the only find of this type of cauldron in the East Midlands."

Most of the cauldrons appear to have been deliberately laid in a large circular enclosure ditch that surrounded a building. They had been placed in either upright or inverted positions, before the ditch was filled in, suggesting that they were buried to mark the cessation of activities associated with this part of the site. Other cauldrons were found buried across the site, suggesting that significant events were being marked over a long period of time as the settlement developed.

The cauldrons are made from several separate parts, comprising iron rims and upper bands, hemispherical copper alloy bowls and two iron ring handles attached to the upper band.

They appear to have been a variety of sizes, with rims ranging between 360mm and 560mm in diameter, with the total capacity of all cauldrons being approximately 550 litres, which illustrates their potential to provide for large groups of people that may have gathered at the settlement from the wider Iron Age community of the area.

John said: "Due to their large capacity it is thought that Iron Age cauldrons were reserved for special occasions and would have been important social objects, forming the centrepiece of major feasts, perhaps in association with large gatherings and events.

"The importance of cauldrons as symbolic objects is reflected in their frequent appearance in early medieval Irish and Welsh literature, which has been drawn upon in studies of Iron Age society. They are rarely found in large numbers and, with the exception of a discovery in Chiseldon, where 17 cauldrons were found in a pit, there have been few excavated examples in recent years."

The cauldrons are extremely fragile and were lifted from site in soil blocks for later analysis.

They were initially investigated at Paul Strickland Scanner Centre in Middlesex, a leading medical imaging centre specialising in cancer which had CT-scanning equipment large enough to accommodate the soil blocks.

Dr Andrew Gogbashian, Consultant Radiologist at Paul Strickland Scanner Centre, said: "We have the latest CT scanning technology and using our medical imaging skills and experience to contribute to such a significant archaeological discovery is a real privilege."

The scans provided useful information in terms of the cauldron orientation, approximate dimensions and profiles, as well as tantalising glimpses of manufacturing methods. Most excitingly the scans also revealed exceptionally rare evidence for decoration from the period, further highlighting the significance of the site.

One example is on a complete cauldron, which has raised stem and leaf motifs on the vessels iron band, close to the handle locations, which are similar to the so-called 'Vegetal Style' of Celtic art, generally dated to the 4th century BC. Another example of decoration has been identified on a small copper alloy bowl fragment, which has a domed rivet or raised boss decoration, suggesting that some of the bowls carried decoration too.

Further detail from the cauldrons will only be possible from excavation and conservation, which is being undertaken by MOLA (Museum of London Archaeology).

Liz Barham, Senior Conservator at MOLA said: "Already we have been able to uncover glimpses of the detailed histories of these cauldrons through CT scanning, including evidence of their manufacture and repair, and have identified sooty residues still clinging to the base of one of the cauldrons from the last time it was suspended over a fire. During the upcoming conservation we hope to discover much more about the entire assemblage. If we're lucky, we may even find food residues from the last time they were used -- over 2000 years ago."

Read more at Science Daily

Possible vestiges of a Universe previous to the Big Bang

Although for five decades, the Big Bang theory has been the best known and most accepted explanation for the beginning and evolution of the Universe, it is hardly a consensus among scientists.

Brazilian physicist Juliano Cesar Silva Neves part of a group of researchers who dare to imagine a different origin. In a study recently published in the journal General Relativity and Gravitation, Neves suggests the elimination of a key aspect of the standard cosmological model: the need for a spacetime singularity known as the Big Bang.

In raising this possibility, Neves challenges the idea that time had a beginning and reintroduces the possibility that the current expansion was preceded by contraction. "I believe the Big Bang never happened," the physician said, who Works as a researcher at the University of Campinas's Mathematics, Statistics & Scientific Computation Institute (IMECC-UNICAMP) in Sao Paulo State, Brazil.

For Neves, the fast spacetime expansion stage does not exclude the possibility of a prior contraction phase. Moreover, the switch from contraction to expansion may not have destroyed all traces of the preceding phase.

The article, which reflects the work developed under the Thematic Project "Physics and geometry of spacetime," considers the solutions to the general relativity equations that describe the geometry of the cosmos and then proposes the introduction of a "scale factor" that makes the rate at which the Universe is expanding depend not only on time but also on cosmological scale.

"In order to measure the rate at which the Universe is expanding with the standard cosmology, the model in which there's a Big Bang, a mathematical function is used that depends only on cosmological time," said Neves, who elaborated the idea with Alberto Vazques Saa, a Full Professor at IMECC-UNICAMP and also the supervisor for Neves' postdoctoral project, funded by the Sao Paulo Research Foundation -- FAPESP.

With the scale factor, Big Bang itself, or cosmologic singularity, ceases to be a necessary condition for the cosmos to begin universal expansion. A concept from mathematics that expresses indefiniteness, singularity was used by cosmologists to characterize the "primordial cosmologic singularity" that happened 13.8 billion years ago, when all the matter and energy from the Universe were compressed into an initial state of infinite density and temperature, where the traditional laws of physics no longer apply.

The Big Bang Theory has its origins in the late 1920s when US astronomer Edwin Hubble discovered that almost all galaxies are moving away from each other at ever-faster velocities.

From the 1940s onward, scientists guided by Einstein's theory of general relativity constructed a detailed model of the evolution of the Universe since the Big Bang. Such model could lead to three possible outcomes: the infinite expansion of the Universe at ever-higher velocities; the stagnation of the Universe expansion in a permanent basis; or an inverted process of retraction caused by the gravitational attraction exerted by the mass of the Universe, what is known as Big Crunch.

"Eliminating the singularity or Big Bang brings back the bouncing Universe on to the theoretical stage of cosmology. The absence of a singularity at the start of spacetime opens up the possibility that vestiges of a previous contraction phase may have withstood the phase change and may still be with us in the ongoing expansion of the Universe," Neves said.

Neves conceptualizes that "bouncing cosmology" is rooted in the hypothesis that Big Crunch would give way to an eternal succession of universes, creating extreme conditions of density and temperature in order to instigate a new inversion in the process, giving way to expansion in another bounce.

Vestiges of contraction

Black holes are the starting point of Neves' investigations about "Bouncing Universe." "Who knows, there may be remains of black holes in the ongoing expansion that date from the prior contraction phase and passed intact through the bottleneck of the bounce," he said.

Consisted of the imploded core remaining after a giant star explodes, black holes are a kind of cosmic object whose core contracted to form a singularity, a point with infinite density and the strongest gravitational attraction known to exist. Nothing escapes from it, not even light.

According to Neves, a black hole is not defined by singularity, but rather by an event horizon, a membrane that indicates the point of no return from which nothing escapes the inexorable destiny of being swallowed up and destroyed by the singularity.

"Outside the event horizon of a regular black hole, there are no major changes, but inside it, the changes are deep-seated. There's a different spacetime that avoids the formation of a singularity."

The scale factor formulated by Neves and Saa was inspired by US physicist James Bardeen. In 1968, Berdeen used a mathematical trick to modify the solution to the general relativity equations that describe black holes.

The trick consisted of thinking of the mass of a black hole not as a constant, as had previously been the case, but as a function that depends on the distance to the center of the black hole. With this change, a different black hole, termed a regular black hole, emerged from the solution to the equations. "Regular black holes are permitted, since they don't violate general relativity. The concept isn't new and has frequently been revisited in recent decades," said Neves.

Since the insertion of a mathematical trick into the general relativity equations could prevent the formation of singularities in regular black holes, Neves considered creating a similar artifice to eliminate the singularity in a regular bounce.

In modern science, a theory is worthless if cannot be verified, however beautiful and inspiring it may be. How do you test the hypothesis of a Big Bang that did not start with a singularity?

Read more at Science Daily

First proper motions measured of stars in a small galaxy outside the Milky Way

The movement of stars depends mostly on the invisible dark matter halo around a galaxy.

By combining data from the Hubble Space Telescope and the Gaia mission, University of Groningen astronomers have been able to measure the proper motion of 15 stars in the Sculptor Galaxy, the first such measurement of stars in a small galaxy outside the Milky Way. Analysis shows an unexpected preference in the direction of movement, which suggests that the standard theoretical models used to describe the motion of stars and dark matter halos in other galaxies might be invalid. The results will be published on 27 November in Nature Astronomy.

Astronomers have long been able to measure the movement of stars in our 'line of sight' (i.e. the movement towards or away from us) by measuring the redshift, which is caused by the Doppler effect. However, measuring the movement in the plane of the sky, what is known as the proper motion, is much more difficult. To detect this, you need multiple precise measurements of a star's position over the course of several years. The immense distances involved mean that many stars in our galaxy move very little across the sky when seen from Earth. For stars outside the galaxy, this movement is even less.

Positions

The European Gaia mission, which is currently underway, was designed to measure the exact location of more than one billion stars, mostly in our own galaxy. 'But Gaia also measures star positions in nearby galaxies', explains University of Groningen astronomer Davide Massari. 'And for some of these stars, we also have their location as measured by the Hubble Space Telescope, some 12 years ago.'

Massari and his colleagues from the Kapteyn Astronomical Institute set out to combine the two data sets. This is not an easy task, as the two missions measure the location in different ways. The team managed to combine the data by using background galaxies which did not change position in the 12 years. 'We had to be very careful to rule out any systematic errors', says Massari. But they succeeded, and out of 120 stars in the Sculptor Galaxy that were measured by both Hubble and Gaia, they found extremely accurate paired observations for 15.

Trajectories

'Next, we determined how the stars move in this small galaxy, which is quantified by the anisotropy parameter', Massari explains. If they are high, the stars have very elongated trajectories and if they are very small, they have circular orbits. 'Knowing this allows us to pin down the properties of the dark matter halo in which the galaxy is embedded. But our measured value was very surprising, as the standard models didn't allow it.' This means that some of the assumptions on which these models are based must be wrong.

'So far, we have only been able to test models by using the line-of-sight movement. That seemed fine, but now, with proper motion, the standard models are breaking down', Massari explains. 'One possible explanation is that the models assume all stars to be in a single population of stars'. But we know Sculptor is complex with at least two stellar populations (one more compact and one more extended). There is a model that includes this and does predict the anisotropy which Massari and colleagues observed, as long as most of the stars they measure belong to the most compact population.

Dark Matter

The movement of stars depends mostly on the invisible dark matter halo around a galaxy. This is why it is so important to determine the anisotropy parameter, because it can be used to pin down the distribution of dark matter in this galaxy, which in turn depends on the nature of dark matter itself. Massari: 'Our results show that by using the Gaia data, combined with other data sets, we can measure the proper motion of stars outside the Milky Way and thus improve the models which describe how dark matter is distributed in these other galaxies.'

Read more at Science Daily

In ‘Shocking’ Discovery, Lightning Triggers Nuclear Reactions

Cloud-to-ground lightning discharge, Tucson, Arizona

If stars are nature’s fusion reactors, then lightning is its particle accelerator. The powerful electrical and magnetic fields generated by a lightning strike emit a flash of gamma rays that burst out in all directions, colliding with atmospheric gases like a celestial game of billiards.

For years, scientists have wondered if these collisions were powerful enough to knock neutrons out of stable nuclei, creating radioactive isotopes of gases like nitrogen and oxygen. Thanks to a powerful winter thunderstorm and some well-placed radiation detectors, a team of Japanese researchers captured the first definitive proof that lightning can trigger a type of nuclear reaction.

As reported Nov. 22 in the journal Nature, a cluster of radiation detectors at the Kashiwazaki-Kariwa nuclear power station on the Sea of Japan recorded gamma ray and positron emissions from an offshore lightning strike on February 6, 2016. The lightning data was exactly what you’d expect to see following photonuclear reactions, the collision of high-energy photons with atmospheric nuclei.

The result of such reactions is a radioactive isotope. Nitrogen-14, for example, is the most abundant particle in the atmosphere, with seven protons and seven neutrons. If a neutron is knocked out of nitrogen-14, it becomes the radioactive isotope nitrogen-13, which quickly decays after just nine seconds into the stable isotope carbon-13.

Before this new lightning discovery, it was believed that all isotopes, both radioactive and stable, were formed in only two ways: from nucleosynthesis in stars, or from collisions in the upper atmosphere between cosmic rays and atmospheric nuclei. The isotope carbon-14, for example, famous for its slow and steady rate of decay, is formed when cosmic rays collide with nitrogen-14 nuclei in the atmosphere, adding a neutron and popping out a proton.

What the Japanese lightning researchers found was an entirely new channel for producing isotopes of nitrogen, carbon, and oxygen, some of which are abundant in nature.

Teruaki Enoto is a physicist and astronomer at Kyoto University in Japan. Back in 2006, he and some collaborators launched the Gamma-Ray Observation of Winter Thunderclouds project, or GROWTH, to try to capture definitive radiation data from lightning storms. After a stint at NASA Goddard Space Flight Center as an X-ray astronomer, Enoto returned to Japan in 2015 and installed several highly sensitive radiation detectors at the nuclear power plant.

Winter storms along the coast of Japan have the dual advantages of being both very powerful and very low to the ground, Enoto told Seeker, making it easier for ground-based detectors like his to capture gamma-rays and other particle emissions.

Enoto said the radiation data captured from a single lightning strike in 2016 points to several exciting new ways of understanding lightning and its role in the universe. First and foremost, the data proved that lightning is a source of at least a small fraction of all radioactive and stable isotopes on Earth, although much more research is needed to figure out how many different isotopes are generated by lightning storms and at what volume.

Second, said Enoto, the new data expands our understanding of lightning’s effects on atmospheric particles, which scientists used to believe was limited to electrons.

“This detection of nuclear reactions implies that nuclei can change in the lightning, which means that nuclear physics can be applied to lightning physics,” he said.

Read more at Seeker

Light Pollution Poses A Growing Threat to Human Health and Biodiversity

The Atlantic Coast of the United States taken at night from the International Space Station on February 6, 2012

Nighttime on Earth is getting brighter.

The rise of developing economies in Africa, Latin America, and Asia isn’t just raising global greenhouse gases emissions and making the planet warmer. It’s also spreading nighttime light to regions of the planet that didn’t have it before, parting the global curtain of night.

“We’re losing more and more of the night on a planetary scale,” Kip Hodges, professor of earth and space exploration at Arizona State University and deputy editor of the journal Science Advances, told Seeker.

The impact won’t just be felt by poets and stargazers.

The dangers, Hodges said, include the “well-established negative effects of light pollution on human health, ecosystems, and astronomical research.”

According to a new paper published in Science Advances, the artificially lit surface of Earth at night increased in radiance and extent by about 2 per cent annually from 2012 to 2016. To make that measurement, Hodges and his team used first-ever calibrated satellite radiometer designed especially for nighttime lights. A radiometer is any device that measures electromagnetic radiation.

An influx of new light can wreak havoc on natural systems that have evolved to live partly in darkness, the authors said.

A big example: nocturnal animals, including some 30 percent of vertebrates and 60 percent of invertebrates.

Indeed, changing night patterns threaten biodiversity, migration, and reproduction habits for a wide range of animals from insects to fish and birds and have an impact on plants and microorganisms, too.

“From an evolutionary perspective now, artificial light at night is a very new stressor,” said Franz Holker, one of the paper’s authors. “The problem is that light has been introduced in places, times and intensities at which it does not naturally occur and many organisms, there is no chance to adapt.”

To be sure, the increase isn’t uniform around the world.

The authors said the change observed in their study varied greatly by country, with some places far exceeding the overall global rate.

Some countries, such as war-torn Yemen and Syria, became darker over the course of the study period.

Some of the world’s brightest nations, like the United States and Spain, remained relatively stable. But most countries in South America, Africa, and Asia became increasingly radiant.

Globally, the increase in light emission appears to correspond closely to the rise in overall economic activity.

For their study, the scientists used a satellite radiometer designed especially for nighttime lights known as a Visible/Infrared Imager Radiometer Suite, or VIIRS.

Notably, the authors point out, VIIRS only detects light emitted between 500 and 900 nanometer wavelengths. It does not “see” blue light (less than 500 nanometers), which humans can see, meaning the increases in brightness detected are even greater with respect to human vision.

Read more at Seeker

Quantum internet goes hybrid

Schematic illustration of a hybrid information network with two quantum nodes composed by a cold cloud of Rubidium (left red cloud) and a doped crystal with Praseodymium ions (right white cube).

In a recent study, published in Nature, ICFO researchers Nicolas Maring, Pau Farrera, Dr. Kutlu Kutluer, Dr. Margherita Mazzera, and Dr. Georg Heinze led by ICREA Prof. Hugues de Riedmatten, have achieved an elementary "hybrid" quantum network link and demonstrated for the first time photonic quantum communication between two very distinct quantum nodes placed in different laboratories, using a single photon as information carrier.

Today, quantum information networks are ramping up to become a disruptive technology that will provide radically new capabilities for information processing and communication. Recent research suggests that this quantum network revolution might be just around the corner.

The key elements of a Quantum Information Network are quantum nodes, that store and process the information, made up of matter systems like cold atomic gases or doped solids, among others, and communicating particles, mainly photons. While photons seem to be perfect information carriers, there is still uncertainty as to which matter system could be used as network node, as each system provides different functionalities. Therefore, the implementation of a hybrid network has been proposed, searching to combine the best capabilities of different material systems.

Past studies have documented reliable transfers of quantum information between identical nodes, but this is the first time this has ever been achieved with a "hybrid" network of nodes. The ICFO researchers have been able to come up with a solution to making a hybrid quantum network work and solve the challenge of a reliable transfer of quantum states between different quantum nodes via single photons. A single photon needs to interact strongly and in a noise-free environment with the heterogeneous nodes or matter systems, which generally function at different wavelengths and bandwidths. As Nicolas Maring states "it's like having nodes speaking in two different languages. In order for them to communicate, it is necessary to convert the single photon's properties so it can efficiently transfer all the information between these different nodes."

How did they solve the problem?

In their study, the ICFO researchers used two very distinct quantum nodes: the emitting node was a laser-cooled cloud of Rubidium atoms and the receiving node a crystal doped with Praseodymium ions. From the cold gas, they generated a quantum bit (qubit) encoded in a single photon with a very-narrow bandwidth and a wavelength of 780 nm. They then converted the photon to the telecommunication's wavelength of 1552 nm to demonstrate that this network could be completely compatible with the current telecom C-band range. Subsequently, they sent it through an optical fiber from one lab to the other. Once in the second lab, the photon's wavelength was converted to 606 nm in order to interact correctly and transfer the quantum state to the receiving doped crystal node. Upon interaction with the crystal, the photonic qubit was stored in the crystal for approximately 2.5 microseconds and retrieved with very high fidelity.

The results of the study have shown that two very different quantum systems can be connected and can communicate by means of a single photon. As ICREA Prof at ICFO Hugues de Riedmatten comments, "being able to connect quantum nodes with very different functionalities and capabilities and transmitting quantum bits by means of single photons between them represents an important milestone in the development of hybrid quantum networks." The ability to perform back- and forth-conversion of photonic qubits at the telecom C-band wavelength shows that these systems would be completely compatible with the current telecom networks.

Advantages of Quantum vs Classical Information Networks

The classical information network or "world wide web" was developed in the 80s, with information flowing through the network by means of "bits," processed and modulated by electronic circuits and chips and transmitted by light pulses that move information thru the network with minimal signal losses via optical fibers.

Now, instead of using the classical bits, quantum information networks (or quantum internet) process and store quantum information through quantum bits or "qubits." While bits can be 0s or 1s, qubits can also be in any superposition of these two states. In a quantum network, they are generated and processed by quantum matter systems, e.g. cold atomic gases, doped solids or other systems. Contrary to classical networks, quantum information is transferred between the nodes using single photons instead of strong light pulses.

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Radiographs of Dolly's skeleton show no signs of abnormal osteoarthritis

Nottingham Dollies are sheep cloned from adult cells, looking similar to this sheep.

Original concerns that cloning caused early-onset osteoarthritis (OA) in Dolly the sheep are unfounded, say experts at the University of Nottingham and the University of Glasgow.

The team, who published last year's Nottingham Dollies research which showed that the 8 year-old Nottingham 'Dollies' had aged normally, have now published a radiographic assessment of the skeletons of Dolly herself, Bonnie (her naturally conceived daughter) and Megan and Morag (the first two animals to be cloned from differentiated cells).

Their findings 'Radiographic assessment of the skeletons of Dolly and other clones finds no abnormal osteoarthritis,' have been published in the online journal Scientific Reports. They show that the skeletons, stored in the collections of National Museums Scotland in Edinburgh, bear radiographic OA similar to that observed in naturally conceived sheep and Nottingham's healthy aged clones.

Kevin Sinclair, Professor of Developmental Biology, in the School of Biosciences, said: "Our findings of last year appeared to be at odds with original concerns surrounding the nature and extent of osteoarthritis in Dolly -- who was perceived to have aged prematurely. Yet no formal, comprehensive assessment of osteoarthritis in Dolly was ever undertaken. We therefore felt it necessary to set the record straight."

Nottingham's Dolly legacy

The four Nottingham 'Dollies' -- Debbie, Denise, Dianna and Daisy -- were derived from the cell line that gave rise to Dolly. They originated from studies undertaken by Professor Keith Campbell between 2005 and 2007 which sought to improve the efficiency of somatic-cell nuclear transfer (SCNT). The Dollies were his legacy to the University of Nottingham.

Kevin Sinclair, together with Sandra Corr, Professor of Small Animal Orthopaedic Surgery who has since moved to Glasgow University, and David Gardner, Professor of Physiology at Nottingham's School of Veterinary Medicine and Science carried out the study into Nottingham's Dollies.

They concluded that the Nottingham Dollies had aged normally with no clinical signs of OA. They had radiographic evidence of only mild or, in one case, moderate OA.

Their results, published July last year in the academic journal Nature Communications, were in apparent stark contrast to Dolly the Sheep's diagnosis of early onset OA which led to scientific concern and media debate over the possibility of early-onset- age-related diseases in cloned animals.

Dolly and osteoarthritis

Reports in 2003 that Dolly, the first animal cloned from adult cells, was suffering from osteoarthritis at the age of 5½ led to considerable scientific concern and media debate over the possibility of early-onset age-related diseases in cloned animals.

However, the only formal record of OA in the original Dolly was a brief mention in a conference abstract which reported that Dolly had OA of the left knee. In the absence of the original records the Nottingham team decided to take to the road and find out for themselves whether the concerns were justified.

Radiographic examinations

They travelled to Edinburgh and, with special permission from Dr Andrew Kitchener, Principal Curator of Vertebrates at National Museums Scotland, undertook radiographic examinations of the skeletons of Dolly and her contemporary clones.

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