Jun 18, 2016

Losing genes and surviving: When 'less is more' in the evolution of life

The chordate O. dioica, despite losing lots of genes, maintains a typical body plan with organs and structures (heart, brain, thyroids, etc.) which can be considered to be homologues to the vertebrates.
"Loss is nothing else but change and change is nature's delight" says the quote by the philosopher and emperor Marcus Aurelius, which opens the scientific article that analyses the gene loss phenomenon and its impact on the evolution of living beings.

The study was published in the magazine Nature Review Genetics and signed by professors Ricard Albalat and Cristian Cañestro, from the Department of Genetics, Microbiology and Statistics and the Biodiversity Research Institute (IRBio) of the University of Barcelona. This article has just been selected as one of the recommended works with special significance in genetics and genomics by the Faculty of 1000 Prime, an international ranking that identifies and re-evaluates the best articles on biology and medicine with the support from a scientific community of more than 10,000 academics worldwide.

Thinking of gene loss as an evolution force is a counterintuitive idea, for it is easier to think that only when we gain something -genes in this case- can we evolve. However the new work by these authors, who are members of the Research Group on Evolution and Development (EVO-DEVO) of the UB, paints the vision of gene loss as a great potential process of genetic change and evolutionary adaption.

Losing genes is also an evolution engine

A gene is lost when the genome is physically removed (by illegitimate recombination, transposition, etc.) or when it is still in the genome but with no use due to a mutation (particular changes, insertions, deficiencies, etc.). "The genome sequencing of very different organisms has shown that gene loss has been a usual phenomenon during evolution in all life cycles. In some cases, it has been proven that this loss might mean an adaptive response towards stressful situations when facing sudden environmental changes" says Professor Cristian Cañestro.

"In other cases, there are genetic losses -says Cañestro- which even though they are neutral per se, have contributed to the genetic and reproductive isolation among lineages, and thus, to speciation, or have rather participated in the sexual differentiation in contributing to the creation of a new Y chromosome. The fact that genetic loss patterns are not stochastic but rather biased in the lost genes (depending on the kind of function of the gen or its situation in the genome in different organism groups) stresses the importance of the genetic loss in the evolution of the species.

Losing to win: an evolutionary paradox

Traditionally, it was believed that insects tended to lose genes. However, the genome sequencing of a beetle (Tribolium castaneum), which proves to have few gen losses, has made it worth reconsidering. In the chordates phylum, which includes vertebrates, there are also some differences among the species, with particular cases such as the planktonic organism Oikopleura dioica -very prone to gen loss.

According to Professor Ricard Albalat, "it has been shown that the possibility of losing genes is linked to the lifestyle of the species. Parasites, for instance, show a greater tendency of gene loss because since they re-use their host's resources, lots of their genes become dispensable and end up disappearing. Species with lots of redundant genes such as the vertebrates and lots of plant species and yeasts which have doubled their genome, have also suffered from gene loss over the course of evolution.

"Interestingly -says Albalat- the massive gene losses are not always linked to radical morphological changes in the affected organism's body plan. The chordate Oikopleura dioica, for example, despite losing lots of genes -some are essential to the embryo development and design of the phylum body plan- maintains a typical body plan with organs and structures (heart, brain, thyroids, etc.) which can be considered to be homologues to the vertebrates'. However, this contradiction, which we have defined as "inverse paradox" of EvoDevo, is still very difficult to explain."

Lost genes in the human evolutionary history

Gene loss can become a positive condition. This has been proved with laboratory experiments (in yeast or bacteria) and population studies on humans. Some of the best studied cases on humans are coding gene losses with cell receptors (CCR5 and DUFFY), which make individuals more resistant to HIV infection and to plasmodium caused by malaria. In nature, there are gene losses from which some organisms benefited: losses which made colour changes in flowers which attract new pollinators, losses which made warmness-resistant insects to be able to colonize new habitats, etc.

Some studies also suggest that gene loss has been decisive in the origins of the human species. Chimpanzees and humans share more than the 98% of their genome -something which has always been of great interest- and in this context it is tempting to speculate that perhaps it would be necessary to look for the differences not in the shared genes but in the lost ones- the ones which have been lost in a different way through the human and primate evolution. "For example, it is believed that gene loss reduced the jaw muscular structure, which allowed the human brain to grow its size, or that gene losses were important in the improvement of our defence system against illnesses," says Cristian Cañestro.

How many gens can a living being lose?

A gene can be lost only if it is dispensable and, therefore, its loss doesn't involve a disadvantage for the individuals. What makes a gene to be dispensable? A gene becomes dispensable when the organism can do its function in an alternative way (functional redundancy) or when the gene is no longer needed because the organism lost its structure or the physiologic requirement in which the gene participated (regressive evolution). For this reason, some changes in the species' lifestyle can turn some genes dispensable, as seen in the gene loss related to pigmentation and vision of the species who adopted cave-dweller ways of life.

Discovering how many genes an organism can lose and how, is something essential to understand how many human genes are dispensable and why certain mutations are irrelevant while others are dramatic for our health. Actually, the recent genome sequencing in individuals from several communities around the world has shown that any healthy person has an average amount of 20 genes not working and it does not seem to provoke any unfavourable consequence.

When genes are dispensable: less is more

According to Ricard Albalat, "probably, the presences of redundant genes or environmental conditions in which we live make us to have less unnecessary genes. Researching on the differences of gene losses among different human communities has allowed, for instance, discovering that lipoprotein A gene loss grants resistance to coronary illnesses among the Finnish population who have fat-rich diets. This experimental approach which relates genes to diseases, called "genotype first," opens the door to the discovery of genes which, when disappearing, give an advantage towards some environmental tensions (diets, climate, toxics, pathogens, etc.) and therefore it could help identifying new genes with therapeutic interests."

Oikopleura dioica: a new model organism in UB's research

Promoting basic research with model organisms (bacteria, mice, yeast, plants, zebrafish, Drosophila or C. elegans) has been a key fact to promote the progress in the field of biomedicine and health. For the scientists, one 21th Century challenge is to develop animal models alternative to the classic ones which can enable applying massive sequencing technologies or also genetic systematic modifications to open new perspectives in the field of basic research. Only by creating basic knowledge is it possible to improve with society's wellbeing.

Nowadays the Evo-Devo-Genomics team of the UB is one of the few research groups around the world which studies the Oikopleura dioica from an evolutionary developmental biology perspective (Evo-Devo). This is also the only team in Spain which has launched a scientific infrastructure -there are two more in Bergen (Norway) and Osaka (Japan)- considered as an international projecting referent with the ability of developing and studying this new model organism.

Read more at Science Daily

Bone artifacts suggest early adoption of poison-tipped arrow technology in Eastern Africa

Stone arrow head (stock image). Bone technology was a central element to the Kuumbi Cave's inhabitants over 13,000 years ago, new research indicates.
Researchers studying bone artefacts discovered in the Kuumbi Cave, Zanzibar, have found evidence to suggest that bone tools were used for hunting, and even as poison arrow tips. The findings, published in the journal Azania: Archaeological Research in Africa, suggest that bone technology was a central element to the Kuumbi Cave's inhabitants over 13,000 years ago.

Bone technology -- such as its use as an arrow tip -- was essential to a Stone Age man's lifestyle and has been shown to have been in use 60,000 years ago. The majority of the evidence to support this has been found in sites in southern Africa, but now the artefacts found in the Kuumbi Cave show that this technology was being adopted in eastern Africa as well.

The researchers investigated seven bone artefacts recovered from the Kuumbi Cave, five bone projectile points, a bone awl, and a notched bone tube. By analysing the artefacts with a camera and microscopes, they were able to compare the manufacture techniques and wear to previous discoveries and to attempts to replicate this technology in the laboratory.

Their findings showed that the bone projectile points are likely to have been used for poison arrows, partly due to the slender and short nature of the arrow heads, and partly supported by a previous discovery of charcoal from the Mkunazi plant, which is known to have poisonous fruit.

The use of poison-tipped arrows by a Stone Age man is thought to have stemmed from a lack of technology and stone-tipped arrows often lack the power to directly kill larger animals, such as zebra or buffalo. Previous work has estimated that poison-tipped arrows may have been used as far back as 24,000 BP (years before present), and the researchers conclude that this technology, better known from southern Africa, may also have been used 13,000 BP in eastern Africa.

From Science Daily

Jun 17, 2016

Did gravitational wave detector find dark matter?

The eight scientists from the Johns Hopkins Henry A. Rowland Department of Physics and Astronomy had already started making calculations when the discovery by the Laser Interferometer Gravitational-Wave Observatory (LIGO) was announced in February. Their results, published recently in Physical Review Letters, unfold as a hypothesis suggesting a solution for an abiding mystery in astrophysics.

"We consider the possibility that the black hole binary detected by LIGO may be a signature of dark matter," wrote the scientists in their summary, referring to the black hole pair as a "binary." What follows are five pages of annotated mathematical equations showing how the researchers considered the mass of the two objects LIGO detected as a point of departure, suggesting that these objects could be part of the mysterious substance known to make up about 85 percent of the mass of the universe.

A matter of scientific speculation since the 1930s, dark matter has recently been studied with greater precision; more evidence has emerged since the 1970s, albeit always indirectly. While dark matter itself cannot yet be detected, its gravitational effects can be. For example, the influence of nearby dark matter is believed to explain inconsistencies in the rotation of visible matter in galaxies.

The Johns Hopkins team, led by postdoctoral fellow Simeon Bird, was struck by the mass of the black holes detected by LIGO, an observatory that consists of two expansive L-shaped detection systems anchored to the ground. One is in Louisiana and the other in Washington State.

Black hole masses are measured in terms of multiples of our sun. The colliding objects that generated the gravity wave detected by LIGO -- a joint project of the California Institute of Technology and the Massachusetts Institute of Technology -- were 36 and 29 solar masses. Those are too large to fit predictions of the size of most stellar black holes, the ultra-dense structures that form when stars collapse. But they are also too small to fit predictions for the size of supermassive black holes at the center of galaxies.

The two LIGO-detected objects do, however, fit within the expected range of mass of "primordial" black holes.

Primordial black holes are believed to have formed not from stars but from the collapse of large expanses of gas during the birth of the universe. While their existence has not been established with certainty, primordial black holes have in the past been suggested as a possible solution to the dark matter mystery. Because there's so little evidence of them, though, the "dark matter is primordial black holes" hypothesis has not gained a large following among scientists.

The LIGO findings, however, raise the prospect anew, especially as the objects detected in that experiment conform to the mass predicted for dark matter. Predictions made by scientists in the past held that conditions at the birth of the universe would have produced lots of these primordial black holes distributed roughly evenly in the universe, clustering in halos around galaxies. All this would make them good candidates for dark matter.

The Johns Hopkins team calculated how often these primordial black holes would form binary pairs, and eventually collide. Taking into account the size and elongated shape believed to characterize primordial black hole binary orbits, the team came up with a collision rate that conforms to the LIGO findings.

"We are not proposing this is the dark matter," said one of the authors, Marc Kamionkowski, the William R. Kenan Jr. Professor in the Department of Physics and Astronomy. "We're not going to bet the house. It's a plausibility argument."

Read more at Science Daily

Bright spots shine light on the future of coral reefs

Marine protected areas support and maintain a rich diversity and abundance of reef fishes in the Rock Islands of Palau, Micronesia.
Researchers have discovered a handful of 'bright spots' among the world's embattled coral reefs, offering the promise of a radical new approach to conservation.

In one of the largest global studies of its kind, researchers conducted over 6,000 reef surveys in 46 countries across the globe, and discovered 15 'bright spots' -- places where, against all the odds, there were a lot more fish on coral reefs than expected.

"Given the widespread depletion of coral reef fisheries globally, we were really excited to find these bright spots that were doing much better than we anticipated," says lead author Professor Josh Cinner from the ARC Centre of Excellence for Coral Reef Studies at James Cook University.

"These 'bright spots' are reefs with more fish than expected based on their exposure to pressures like human population, poverty, and unfavourable environmental conditions.

"To be clear, bright spots are not necessarily pristine reefs, but rather reefs that have more fish than they should, given the pressures they face.

"We wanted to know why these reefs could 'punch above their weight' so-to-speak, and whether there are lessons we can learn about how to avoid the degradation often associated with overfishing."

Co-author, Professor Nick Graham of Lancaster University says globally, coral reefs are in decline and current strategies for preserving them are insufficient.

"Our bright spots approach has identified places we did not previously know were so successful, and the really interesting thing is that they are not necessarily untouched by man," he says.

"We believe their discovery offers the potential to develop exciting new solutions for coral reef conservation."

"Importantly, the bright spots had a few things in common, which, if applied to other places, might help promote better reef conditions."

"Many bright spots had strong local involvement in how the reefs were managed, local ownership rights, and traditional management practices," says co-author Dr. Christina Hicks of Lancaster and Stanford Universities.

The scientists also identified 35 'dark spots' -- these were reefs with fish stocks in worse shape than expected.

"Dark spots also had a few defining characteristics; they were subject to intensive netting activities and there was easy access to freezers so people could stockpile fish to send to the market," says Dr. Hicks.

This type of bright spots analysis has been used in fields such as human health to improve the wellbeing of millions of people. It is the first time it has been rigorously developed for conservation.

"We believe that the bright spots offer hope and some solutions that can be applied more broadly across the world's coral reefs," says Prof. Cinner.

"Specifically, investments that foster local involvement and provide people with ownership rights can allow people to develop creative solutions that help defy expectations of reef fisheries depletion.

"Conversely, dark spots may highlight development or management pathways to avoid."

Read more at Science Daily

Unexpected Excess of Giant Planets in Star Cluster Messier 67

An international team of astronomers have found that there are far more planets of the hot Jupiter type than expected in a cluster of stars called Messier 67. This surprising result was obtained using a number of telescopes and instruments, among them the HARPS spectrograph at ESO's La Silla Observatory in Chile. The denser environment in a cluster will cause more frequent interactions between planets and nearby stars, which may explain the excess of hot Jupiters.

A Chilean, Brazilian and European team led by Roberto Saglia at the Max-Planck-Institut für extraterrestrische Physik, in Garching, Germany, and Luca Pasquini at ESO, has spent several years collecting high-precision measurements of 88 stars in Messier 67. This open star cluster is about the same age as the Sun and it is thought that the Solar System arose in a similarly dense environment.

The team used HARPS, along with other instruments, to look for the signatures of giant planets on short-period orbits, hoping to see the tell-tale "wobble" of a star caused by the presence of a massive object in a close orbit, a kind of planet known as a hot Jupiters. This hot Jupiter signature has now been found for a total of three stars in the cluster alongside earlier evidence for several other planets.

A hot Jupiter is a giant exoplanet with a mass of more than about a third of Jupiter's mass. They are "hot" because they are orbiting close to their parent stars, as indicated by an orbital period (their "year") that is less than ten days in duration. That is very different from the Jupiter we are familiar with in our own Solar System, which has a year lasting around 12 Earth- years and is much colder than the Earth.

"We want to use an open star cluster as laboratory to explore the properties of exoplanets and theories of planet formation," explains Roberto Saglia. "Here we have not only many stars possibly hosting planets, but also a dense environment, in which they must have formed."

The study found that hot Jupiters are more common around stars in Messier 67 than is the case for stars outside of clusters. "This is really a striking result," marvels Anna Brucalassi, who carried out the analysis. "The new results mean that there are hot Jupiters around some 5% of the Messier 67 stars studied -- far more than in comparable studies of stars not in clusters, where the rate is more like 1%."

Astronomers think it highly unlikely that these exotic giants actually formed where we now find them, as conditions so close to the parent star would not initially have been suitable for the formation of Jupiter-like planets. Rather, it is thought that they formed further out, as Jupiter probably did, and then moved closer to the parent star. What were once distant, cold, giant planets are now a good deal hotter. The question then is: what caused them to migrate inwards towards the star?

There are a number of possible answers to that question, but the authors conclude that this is most likely the result of close encounters with neighbouring stars, or even with the planets in neighbouring solar systems, and that the immediate environment around a solar system can have a significant impact on how it evolves.

Read more at Science Daily

800,000-Year-Old Footprints Found in Desert

Researchers digging in the desert of southeast Eritrea have uncovered what could be the first footprints that are clearly attributed to Homo erectus, a species of hominid widely considered to be a direct ancestor to modern humans.

Estimated to feature a size 12 foot size, the fossilized footprints were possibly made by tall individuals some 800,000 years ago in sandy sediments along the shores of what was once a large lake surrounded by grasslands.

Today the Aalad-Amo site where the H. erectus's prints were excavated by a team of the National Museum of Eritrea and Rome's La Sapienza University is occupied by the semi arid Danakil desert.

"The prints are preserved on a hardened sandy sediment that was partly flooded. So far we have been able to bring to light a portion of 85 square feet," Alfredo Coppa, the anthropologist from Rome's Sapienza University who led the dig, told Discovery News.

Coppa explained the slab of stone features footprints which move from north to south and possibly belong to several individuals. They may have been stalking an antelope-like animal whose prints were also recognized in the trackway.

"Homo erectus was the only hominid species that inhabited the area at that time. Indeed, these could be the first clearly recognizable H. erectus's footprints," Coppa said.

The large-brained H. erectus is very important to the study of human evolutionary history. The species emerged 1.8 million years ago and went extinct in Africa around 800,000-700,000 years ago. It spread from eastern Africa to the Middle East and Asia, where it may have survived up to 50,000 years ago.

Appearing very similar to those of modern man, the fingerprints from Eritrea may provide important clues on how H. erectus's gait evolved until Homo sapiens, a species physically close to modern humans, came about around 200,000 years ago.

"The prints show toe details, a marked longitudinal arch and an abducted toe, all features distinctive of human feet," Coppa said.

He noted that footprints can offer a series of insights -- such as information on the body mass, gait and even social behavior if they belong to several individuals -- that skeletal and skull remains can't provide.

But fossilized human prints are extremely rare. In Africa only three footprint sites were discovered. One, found in Laetoli, Tanzania, is 3.7 million years old and represents the earliest direct evidence of hominin bipedalism. The prints were made by Australopithecus afarensis, an hominin that lived between 3.9 and 2.9 million years ago and whose best known specimen is the famous Lucy.

Other two sites in Kenya, at Ileret and Koobi Fora, are dated to 1.5-1.4 million years ago and display prints of different homind species.

Read more at Discovery News

As Planet Warms, Resurfaced Relics Threatened

An old wooden shipwreck in Tisnes, near Tromsø, Norway.
Climate change and its various effects, from melting polar ice and thawing permafrost to rising sea levels and violent storms, are exposing ancient relics and remains at an increasing rate across the planet, threatening them with rapid deterioration and endangering a major source of our knowledge about the past.

New Scientist reports that some archaeologists are so alarmed about the damage being done to these materials by global warming that they're urging colleagues to step away from their excavation sites and rush to preserve the suddenly-revealed specimens.

The destruction, ironically, is coming at a time when scientists have recently-developed techniques--ranging from sequencing of ancient DNA to chemical analysis of tooth plaque that shed insights about an ancient human's diet--that would provide us with a wealth of information about antiquity.

"The archive is being destroyed just as we are able to read it," Thomas McGovern, an archaeologist at the City University of New York, told New Scientist.

In once-frozen areas of the northern hemisphere, melting glaciers are exposing frozen remains of ancient humans and animals faster than researchers can recover them, Scientific American reported in 2015.

To the south,when archaeologists uncover mummies from the Chinchorro civilization, which existed 7,000 years ago in northern Chile and Peru, they're finding signs of increasingly rapid deterioration, as the climate in that region has become increasingly moist, according to a 2015 Los Angeles Times article.

Some scientists also are taking advantage of opportunities for finds created by climate change. According to New Scientist, receding sea ice around Norway's Svalbard archipelago has opened up previously inaccessible areas, allowing marine archaeologist Øyvind Ødegård to search for shipwrecks in the area that date back to the late 1500s.

Even so, Ødegård reportedly was alarmed to discover a piece of driftwood in the area that was infested with shipworm, a voracious wood-consuming mollusc, which previously was thought to be unknown in the waters because it was too cold. If shipworm has invaded the waters due to climate shifts, it could pose a threat to the wrecks that haven't yet been investigated.

From Discovery News

Jun 16, 2016

Small planets hiding in giant cloaks

An artist's illustration of a hot Neptune-sized world moving behind its host star.
Hazes and clouds high up in the atmospheres of exoplanets may make them appear bigger than they really are, according to new research by astronomers at the Space Research Institute (IWF) of the Austrian Academy of Sciences. The team, led by Helmut Lammer, publish their results in a letter to Monthly Notices of the Royal Astronomical Society.

Since the first confirmed discovery in 1993, astronomers have found more than 3,000 planets in orbit around stars other than our Sun. A key goal now is to characterise known worlds by mass, size and composition, to better understand the evolution of planetary systems, and the prospects for 'Earthlike' planets that might support life.

In 2014 Lammer and his team used the European Space Agency (ESA) CoRoT space telescope to study the upper atmosphere of two low-mass planets that are regularly seen to pass in front of (transit) the star they orbit. The two planets orbit their star in 5 and 12 days, appear to be around 4 and 5 times the diameter of the Earth, and have respective masses of less than 6, and 28 times Earth. The outer, more massive planet, CoRoT-24c, is similar in mass to Neptune. In contrast, the inner planet, CoRoT-24b, is less than a quarter as massive, but is similar in size, so seems to have a very low density.

With such short orbits, both worlds are close to and will experience dramatic heating from the star. The team modelled this and found that the lower mass planet would see its atmosphere evaporate within 100 million years, if it really is as big as suggested. But the star is billions of years old, so the planet should have lost its atmosphere long ago.

The solution seems to be that the planet is only about half as big as thought. Lammer argues that an extended, very thin, atmosphere, surrounds a relatively compact planet, but has high altitude features that confuse observations. He explains: "The radius is based on what we see when the planet makes its transit. This is probably distorted by clouds and haze high in the atmosphere, in a region where atmospheric pressure is otherwise very low."

Co-author Luca Fossati adds that this effect needs to be considered by future exoplanet missions, like the ESA CHaracterising ExOPlanets Satellite (CHEOPS) mission due to launch in December 2017. Results for some worlds found by the NASA Kepler observatory may also need to be re-evaluated.

"Our results show that CHEOPS scientists need to be cautious about their first measurements," says Fossati.

"Since Kepler has also discovered several similar low-density and low-mass planets, it is very likely that the size measured for many of them also differ from the true value, so there could be a bias in the results."

Read more at Science Daily

Black holes and the prospects for measuring gravitational waves

An artist's concept of a supermassive black hole at the centre of a galaxy.
The supermassive black holes found at the centre of every galaxy, including our own Milky Way, may, on average, be smaller than we thought, according to work led by University of Southampton astronomer Dr Francesco Shankar. If he and his colleagues are right, then the gravitational waves produced when they merge will be harder to detect than previously assumed. The international team of scientists publish their result in Monthly Notices of the Royal Astronomical Society.

Black holes play a fundamental role in astronomy, gravitation, and particle physics. They are enormously concentrated masses, sometimes millions to billions of times more massive than the Sun, and have gravitational fields that are so powerful that not even light travels fast enough to escape their grasp, hence the name ‘black hole’.

Supermassive black holes have been found lurking in the cores of all galaxies observed with high enough sensitivity. Despite this, little is known about how they formed. What is known is that the mass of a supermassive black hole at the centre of a galaxy is related to the total mass and the typical speeds (the "velocity dispersion") of the stars in its host.

The very existence of this relationship suggests a close co-evolution between black holes and their host galaxies, and understanding their origin is vital for a proper model of how galaxies and black holes form and evolve. This is because many galaxy evolution models invoke powerful winds and/or jets from the central supermassive black hole to control or even stop star formation in the host galaxy (so-called "quasar feedback"). Alternatively, multiple mergers of galaxies - and their central black holes - are also often suggested as the primary drivers behind the evolution of massive galaxies.

Despite major theoretical and observational efforts in the last decades, it remains unclear whether quasar feedback actually ever occurred in galaxies, and to what extent mergers have truly shaped galaxies and their black holes. Some of this is because modellers have had a tough time reproducing the observed black-hole galaxy scaling relations, and in reconciling the properties of nearby black holes with more distant populations.

The new work shows that selection effects – where what is observed is not representative - have significantly biased the view of the local black hole population. This bias has led to significantly overestimated black hole masses. It suggests that modellers should look to velocity dispersion rather than stellar mass as the key to unlocking the decades-old puzzles of both quasar feedback and the history of galaxies.

With less mass than previously thought, supermassive black holes have on average weaker gravitational fields. Despite this, they were still able to power quasars, making them bright enough to be observed over distances of billions of light years.

Unfortunately, it also implies a substantial reduction in the expected gravitational wave signal detectable from pulsar timing array experiments. Ripples in spacetime that were first predicted by Albert Einstein in his general theory of relativity in 1915; gravitational waves were finally detected last year and announced by the LIGO team this February. The hope is that coming observatories can observe many more gravitational wave events, and that it will provide astronomers with a new technique for observing the universe.

Dr Shankar comments: “Gravitational wave astronomy is opening up an entirely new way of observing the universe. Our results though illustrate how challenging a complete census of the gravitational background could be, with the signals from the largest black holes being paradoxically among the most difficult to detect with present technology.”

Researchers expect pairs of supermassive black holes, found in merging galaxies, to be the strongest sources of gravitational waves in the universe. However, the more massive the pairs, the lower the frequencies of the emitted waves, which become inaccessible to ground based interferometers like LIGO. Gravitational waves from supermassive black holes can however be detected from space via dedicated gravitational telescopes (such as the present and future ESA missions LISA pathfinder and eLISA), or by a different method using ‘pulsar timing arrays’.

Read more at Science Daily

Modern mussel shells much thinner than 50 years ago

Cross section of a mussel shell showing its thickness. The holes show where samples were drilled to analyze its composition.
Shells of California mussels collected from the Pacific Ocean off the coast of Washington in the 1970s are on average 32 percent thicker than modern specimens, according to a new study published by University of Chicago biologists.

Shells collected by Native Americans 1,000 to 1,300 years ago were also 27 percent thicker than modern shells, on average. The decreasing thickness over time, in particular the last few decades, is likely due to ocean acidification as a result of increased carbon in the atmosphere.

"Archival material provided by past researchers, the Makah Tribal Nation, and the Olympic National Park allowed us to document this intriguing and concerning pattern in shell thickness," said Cathy Pfister, PhD, professor of ecology and evolution at the University of Chicago and lead author. The study was published June 15, 2016, in the Proceedings of the Royal Society B.

As humans burn fossils fuels, the oceans absorb a large portion of the additional carbon released into the atmosphere. This in turn causes pH levels of ocean water to drop, making it more acidic. Mussels, oysters, and certain species of algae have difficulty producing their calcium carbonate shells and skeletons in such an environment, and can provide an early indicator of how increasing ocean acidification affects marine life.

In previous studies, Pfister and her colleagues documented declining pH levels in the waters surrounding Tatoosh Island off the coast of Washington state. In 2011 they further analyzed carbon and oxygen isotopes taken from modern mussel shells, shells collected by the local Makah tribe between AD 668 and 1008, and shells collected by biologists in the 1970s.

For the new study, the researchers compared the thicknesses of the same sets of shells. On average, the shells provided by the Makah Cultural and Research Center were 27.6 percent thicker than modern counterparts. Shells from the 1970s were 32.2 percent thicker. Shells collected from a different Native American site in Sand Point, WA, dating between 2150 and 2420 years old were almost 94 percent thicker than modern shells.

The long-term decline in thickness likely shows a response to ocean acidification, though the researchers also consider other environmental drivers including changes in food supply (e.g. plankton) for mussels.

The researchers also point out that their findings raise concerns about the California mussel's ability to retain its role as a foundational species in these waters. Decreased shell thickness makes them increasingly vulnerable to predators and environmental disturbances. This in turn could affect interactions with hundreds of other species of organisms that live near mussel beds in tidal waters.

Read more at Science Daily

Tadpoles hatch in seconds to escape predator

Red-eyed treefrog embryos hatch to escape from a cat-eyed snake.
Although red-eyed tree frog embryos appear helpless within their jelly-coated eggs, they can hatch up to two days ahead of schedule, reacting within seconds to attacks by egg thieves. At the Smithsonian Tropical Research Institute (STRI) in Panama, scientists used high-speed video to uncover their rapid-hatching secret.

"Most people think of embryos as fairly passive," said Karen Warkentin, STRI research associate and professor at Boston University. "But evidence keeps accumulating that embryos of many species are actively engaged with their world, not only receiving information but also using it to do things that help them survive."

This is particularly true of the embryos of red-eyed tree frogs (Agalychnis callidryas). Native to Neotropical rainforests, adult frogs live in trees and lay clusters of 40 or so eggs on leaves, branches or other structures that overhang ponds or streams. Left undisturbed, tadpoles hatch after a week's development inside the gooey egg mass and drop into the water below. But the eggs are often attacked by hungry snakes or wasps and are also vulnerable to sudden environmental events like floods or heavy downpours. Developing embryos are able to assess the level of threat and have evolved a quick-release mechanism to escape the egg prematurely.

In a project led by Warkentin's doctoral student, Kristina Cohen, the scientists collected and studied egg clusters at STRI's open-air laboratory in Gamboa, Panama. By physically manipulating the embryos to simulate the vibrations caused by predators, they triggered escape responses captured on video.

"They do a shaking behavior while releasing enzymes from glands concentrated on their snouts," Warkentin said. "That movement seems to push them snout-first against the hole the enzyme makes in the egg membrane. Then they muscle their way out by using big, S-shaped thrashing movements."

The study, published in the Journal of Experimental Biology, reported that hatching took between six and 50 seconds, with an average of 20 seconds for the premature tadpoles to drop from their perches. Warkentin says some tadpoles hatched even faster in the wild, when threatened by a real snake.

Using scanning electron microscopes, the researchers compared hatching glands of undisturbed embryos within the egg with those of tadpoles immediately after hatching. Undisturbed gland cells contain swollen sacs of hatching enzyme. In the cells of newly hatched tadpoles, these sacs appeared shrunken. The tadpoles use the glands to release a precision-strike squirt of enzyme to make a hole when they are ready to burst for freedom. In contrast, the embryos of other frog species laid in water often have hatching glands scattered all over their bodies, which release enzymes slowly, over a matter of hours or days.

With more than 7,000 species of amphibians currently known throughout the world, many more survival strategies remain to be discovered. The new study suggests that it is not just tadpoles and adults that strive to life's challenges. "The process of getting out of the egg is the embryo's first, tiny, athletic event," Warkentin said.

Read more at Science Daily

Jun 15, 2016

First detection of methyl alcohol in a planet-forming disc

The protoplanetary disc around the young star TW Hydrae is the closest known example to Earth, at a distance of only about 170 light-years. As such it is an ideal target for astronomers to study discs. This system closely resembles what astronomers think the Solar System looked like during its formation more than four billion years ago.

The Atacama Large Millimeter/Submillimeter Array is the most powerful observatory in existence for mapping the chemical composition and the distribution of cold gas in nearby discs. These unique capabilities have now been exploited by a group of astronomers led by Catherine Walsh (Leiden Observatory, the Netherlands) to investigate the chemistry of the TW Hydrae protoplanetary disc.

The ALMA observations have revealed the fingerprint of gaseous methyl alcohol, or methanol (CH3OH), in a protoplanetary disc for the first time. Methanol, a derivative of methane, is one of the largest complex organic molecules detected in discs to date. Identifying its presence in pre-planetary objects represents a milestone for understanding how organic molecules are incorporated into nascent planets.

Furthermore, methanol is itself a building block for more complex species of fundamental prebiotic importance, like amino acid compounds. As a result, methanol plays a vital role in the creation of the rich organic chemistry needed for life.

Catherine Walsh, lead author of the study, explains: "Finding methanol in a protoplanetary disc shows the unique capability of ALMA to probe the complex organic ice reservoir in discs and so, for the first time, allows us to look back in time to the origin of chemical complexity in a planet nursery around a young Sun-like star."

Gaseous methanol in a protoplanetary disc has a unique importance in astrochemistry. While other species detected in space are formed by gas-phase chemistry alone, or by a combination of both gas and solid-phase generation, methanol is a complex organic compound which is formed solely in the ice phase via surface reactions on dust grains.

The sharp vision of ALMA has also allowed astronomers to map the gaseous methanol across the TW Hydrae disc. They discovered a ring-like pattern in addition to significant emission from close to the central star.

The observation of methanol in the gas phase, combined with information about its distribution, implies that methanol formed on the disc's icy grains, and was subsequently released in gaseous form. This first observation helps to clarify the puzzle of the methanol ice-gas transition, and more generally the chemical processes in astrophysical environments.

Read more at Science Daily

When it comes to evolution, testes may play a key role, studies find

The slate-colored junco, left, found in Virginia's Appalachian Mountains, is small with subtle plumage. The white-winged junco of the Black Hills of South Dakota is larger and flashier.
A pair of studies led by Indiana University researchers provide new evidence that when it comes to evolution, the testes may play a key role.

The research, led by Kimberly Rosvall, assistant professor in the IU College of Arts and Sciences' Department of Biology, finds that the testes -- or gonads -- have a greater impact than previously thought in evolution. The research was conducted in two subspecies of dark-eyed junco, a type of American sparrow.

The white-winged junco, or Junco hyemalis aikeni, is found in the Black Hills of South Dakota. The slate-colored junco, or Junco hyemalis carolinensis, is from the Appalachian Mountains in Virginia. The first is larger and more aggressive; the other is smaller and more docile.

The studies are published in the journals of Hormones and Behavior and of Integrative and Comparative Biology.

The first paper compares the subspecies in their expression of enzymes that make testosterone within the gonad. The second paper investigates how the subspecies' gonads differ in the expression of stress hormone receptor genes, which are known to lower testosterone.

"The majority of endocrinologists will tell you that testosterone-mediated traits such as physical appearance or behavior are regulated in a top-down fashion -- that the brain acts as the 'CEO,' telling the rest of the body what to do," Rosvall said. "But our data suggest that this CEO model is oversimplified, and that the workers in the testosterone 'factory' -- the gonad -- may actually play an important role in trait divergence."

Compared to the Virginia juncos, the South Dakota birds are not only larger and more aggressive, they also boast flashier plumage, including more white tail feathers and prominent white bars on their wings. All these traits are influenced by testosterone, which is widely recognized in biology to influence traits important in natural selection, such as survival and reproduction.

Within a population, some males produce more testosterone, others produce less. Over evolutionary time, average levels of testosterone -- and the traits that testosterone regulates, such as aggression, body size, and even parental care or sex drive -- may evolve to suit a given environment. The genomic mechanisms that allow testosterone levels to evolve, however, are not well understood.

To conduct their research on the topic, Rosvall and colleagues studied the gonads of the two subspecies in the wild and in captivity. In the case of the South Dakota juncos, the results suggested the brawnier birds' gonads simply had more abundant testosterone-producing machinery. When the researchers treated the birds with a testosterone-stimulating hormone, the South Dakota birds were able to make more testosterone faster and keep it elevated longer.

"An animal that keeps testosterone elevated for longer should have greater expression of these testosterone-mediated characteristics," Rosvall said.

In the second study, Rosvall and colleagues found an additional cause for lower testosterone levels in the Virginia juncos. The smaller birds' testes expressed higher levels of stress hormone receptors -- known inhibitors of the production of testosterone.

The mechanism by which testosterone results in different traits involves hormone receptors found in the brain and body. When testosterone binds to these sites, it affects the expression of genes that influence characteristics such as behavior, body size and plumage.

"At the genomic level, you can really see a significant difference between these big, sexy juncos and their smaller, less aggressive cousins," Rosvall said. "Because we still saw some of these differences in males that we captured as juveniles, our research suggests that these differences in the gonad are genetic, or programmed very early in life."

The results are significant because they challenge the prevailing theory that hormonally regulated trait differences between species are controlled largely by the brain. In earlier studies, the IU team looked at various aspects of the brain and the pituitary, a gland that acts as an intermediary between the brain and the gonad, with results that suggested some difference between the gonads in high- versus low-testosterone males.

Read more at Science Daily

How the butterfly got its spots

By tweaking just one or two genes, Cornell University researchers have altered the patterns on a butterfly's wings. This image shows normal and engineered wing patterns as mirror images.
By tweaking just one or two genes, Cornell University researchers have altered the patterns on a butterfly's wings. It's not just a new art form, but a major clue to understanding how the butterflies have evolved, and perhaps to how color patterns -- and other patterns and shapes -- have evolved in other species.

By using the new method of CRISPR genome editing, researchers cut out a gene known as spalt, and produced a butterfly lacking the large round markings known as eyespots. In another experiment, they removed a gene known as distal-less and produced more and larger eyespots. The experiments also produced changes in other parts of the wing design.

The distal-less gene in particular revealed itself as a jack-of-all-trades gene that plays roles in shaping several parts of the body. Deleting it not only caused the butterfly to have extra eyespots, but to have shorter legs and antennae.

"People suspected these genes had something to do with wing patterns but nobody had proved it," said Robert Reed, associate professor of ecology and evolutionary biology. "It probably takes dozens or hundreds of genes to make an eyespot, so it was remarkable to find that only one or two genes are required to add or subtract these complex patterns. It is a beautiful demonstration of how animals are assembled as modules, much like a model kit." Reed and postdoctoral researcher Linlin Zhang report their results in the TK issue of the journal Nature Communications.

Butterfly wing patterns are of special interest to evolutionary biologists because they provide an easily accessible model of how natural selection chooses from many possible variations. "Variation is the raw material of evolution," Reed said. CRISPR genome editing technology offers great potential for understanding how this variation originates he added.

Butterfly wing designs can be a defense against predators. Some butterflies are poisonous to birds (or maybe just taste bad) and birds can learn to recognize the designs that say "I'm not good to eat." Other butterflies have evolved to mimic dangerous species. The large round markings on some butterfly and moth wings have come to be called "eyespots" because the spread out wings of the insect may look to a predator like the face of something big and dangerous. The designs also influence mate selection.

Read more at Science Daily

Underwater Remains of Ancient Naval Base Found

Danish and Greek archaeologists have discovered the remains of one of the largest building complexes of the ancient world -- a naval base that 2,500 years ago housed Athens's enormous fleet.

Featuring massive harbor fortifications and sheds designed to hold hundreds of war ships called triremes, the base played a key role in the most decisive naval battle of antiquity.

The remains lay hidden under the water of the Mounichia fishing and yachting harbor in the Piraeus.

University of Copenhagen archaeologist Bjørn Lovén, who led the expedition as part of the Zea Harbor Project, identified and excavated six ship-sheds that were used to protect the Greek ships from shipworm and from drying when they were not needed on the sea.

"The sheds were monumental," Lovén said.

He noted the foundations under the columns were 4 foot by 6 inches and the sheds themselves were just over 19 feet wide, up to 26 feet tall and 164 feet long.

Based on pottery and carbon-14 dating from a worked piece of wood found inside the foundations of a colonnade dividing two ship-sheds, Lovén and colleagues dated the structure to around 520-480 B.C. or shortly thereafter.

Such evidence means the ship-sheds in all probability housed the warships that were deployed in 480 B.C. in the famous naval battle of Salamis between the Greeks and Persians.

Fought in the narrow straits that separate the Greek mainland from the island of Salamis, the battle is regarded as one of the greatest and most important naval engagements of antiquity. The Greeks's three-tiered warships, led by the Athenian politician and general Themistocles, defeated the much larger invading Persian fleet led by King Xerxes, who intended to add Greece to the greatest empire on Earth.

"All social classes rowed and fought aboard the triremes. I strongly believe this pivotal battle created an immensely strong bond among most of the citizens, and in this way the Athenian navy was to develop into the backbone of the world's first democracy," Lovén told Discovery News.

Read more at Discovery News

Jun 14, 2016

Cats seem to grasp the laws of physics

Cats understand the principle of cause and effect as well as some elements of physics. Combining these abilities with their keen sense of hearing, they can predict where possible prey hides. These are the findings of researchers from Kyoto University in Japan, led by Saho Takagi and published in Springer's journal Animal Cognition.

Previous work conducted by the Japanese team established that cats predict the presence of invisible objects based on what they hear. In the present study, the researchers wanted to find out if cats use a causal rule to infer if a container holds an object, based on whether it is shaken along with a sound or not. The team also wanted to establish if cats expect an object to fall out or not, once the container is turned over.

Thirty domestic cats were videotaped while an experimenter shook a container. In some cases this action went along with a rattling sound. In others it did not, to simulate that the vessel was empty. After the shaking phase, the container was turned over, either with an object dropping down or not.

Two experimental conditions were congruent with physical laws, where shaking was accompanied by a (no) sound and an (no) object to fall out of the container. The other two conditions were incongruent to the laws of physics. Either a rattling sound was followed by no object dropping out of the container or no sound while shaking led to a falling object.

The cats looked longer at the containers which were shaken together with a noise. This suggests that cats used a physical law to infer the existence (or absence) of objects based on whether they heard a rattle (or not). This helped them predict whether an object would appear (or not) once the container was overturned.

The animals also stared longer at containers in incongruent conditions, meaning an object dropped despite its having been shaken noiselessly or the other way around. It is as if the cats realized that such conditions did not fit into their grasp of causal logic.

"Cats use a causal-logical understanding of noise or sounds to predict the appearance of invisible objects," says Takagi.

Read more at Science Daily

Palaeontologist discovers new species of 200 million-year-old 'British' marine reptile

Cast of a Mesozoic Ichthyosaur
A new type of ichthyosaur, an extinct marine reptile alive at the same time as the dinosaurs, has been identified by a Manchester palaeontologist from a fossil found in an old quarry in Nottinghamshire.

Similar-shaped to dolphins and sharks, ichthyosaurs -- often misidentified as 'swimming dinosaurs' -- swam the seas of Earth for millions of years during the Triassic, Jurassic and Cretaceous periods. The Nottinghamshire fossil is from the earliest part of the Jurassic Period -- 200 million years ago -- and only a handful of ichthyosaur species are known from this period, making the discovery very significant. It is also the first time a species of this geological age has been found outside of Dorset and Somerset.

Dean Lomax, a Palaeontologist and Honorary Scientist at The University of Manchester, examined the specimen after seeing it on a visit to Leicester's New Walk Museum, which acquired the fossil in 1951, and spotted some unusual features. The specimen is relatively complete, consisting of a partial skeleton including a skull, pectoral bones, limbs, pelvis bones, ribs and vertebrae. However, the bones are disorderly -- it appears that the carcass 'nosedived' into the seabed before it became fossilised, which may have restricted previous study.

"When I first saw this specimen, I knew it was unusual," said Dean. "It displays features in the bones -- especially in the coracoid (part of the pectoral girdle) -- that I had not seen before in Jurassic ichthyosaurs anywhere in the world. The specimen had never been published, so this rather unusual individual had been awaiting detailed examination."

Dr Mark Evans, Palaeontologist and Curator of Natural Sciences at New Walk Museum, said: "Parts of the skeleton had previously been on long-term loan to ichthyosaur specialist and former museum curator Dr Robert Appleby, and had only returned to the museum in 2004 after he sadly passed away. He was clearly intrigued by the specimen, and although he worked on it for many years, he had identified it as a previously known species but never published his findings."

Dean has named the new species Wahlisaurus massarae in honour of two palaeontologists (Professor Judy Massare and Bill Wahl) who have contributed significantly to the study of ichthyosaurs, and who first introduced Dean to studying them.

"Both Judy and Bill have been tremendous mentors for me. They have significantly contributed to palaeontology, especially the study of ichthyosaurs, and I cannot think of a better way to remember them by naming this new ichthyosaur in their honour. Their names will be set in stone forever, pun intended!"

Read more at Science Daily

Mammal Dads Matter More Than Previously Thought

When a mammal dad provides fatherly care, such as feeding hungry young and toting sons and daughters, he usually gets more matings with mom as well as larger litters, finds an extensive new study.

This means that fatherly care goes hand in hand with the reproductive success of mothers, according to the research, which is published in the journal Nature Communications.

While the study doesn't name the top dads among mammals, co-author Isabella Capellini offered some possibilities.

"Anecdotally we can say that in wolves, foxes and other dog-like species, males provide a substantial amount of care, such as providing food; while in New World monkeys, like marmosets and tamarinds, males carry their offspring for long periods of time even when the young become very heavy," said Capellini, a senior lecturer in vertebrate zoology at the University of Hull.

Capellini and co-author Hannah West, also from the University of Hull, analyzed fatherly care -- or lack thereof -- among 529 mammal species. Only 10 percent of all mammals have males that either directly or indirectly help to care for their little ones, leading to the deadbeat dad reputation of the rest.

This is often not the case for non-mammals.

"In other animals, such as most birds, males contribute substantially in raising the offspring," Capellini said. "In some frogs and fish, only one parent provides care, with fish having several species where only the father cares for eggs and hatched offspring."

For mammals, it appears that there are significant drawbacks associated with being a caring father. These can include missed mating opportunities with other females, greater risk of predation, loss of precious time and energy and more, the researchers note.

The benefits of being what we would consider to be a good dad, on the other hand, include a higher probability of offspring survival and less running around to find a mate. The doting dads in the study engaged in behaviors such as carrying their young, offering food to moms and babies, huddling with their family and grooming them.

As for why some mammal dads are more caring than others, the researchers believe that such behavior is likely to evolve when males gain a greater certainty of paternity or when future mating opportunities are scarce.

The researchers suspect that offspring of mammal species where both parents provide care grow up much faster.

"For example," Capellini said, "heavier pups among wolves and dogs are more likely to survive winter than lighter siblings, and the resources provided by the father should allow them to reach a larger size faster."

Charlotta Kvarnemo, a professor in the Department of Biological and Environmental Sciences at the University of Gothenburg, told Discovery News that the results of the new study "are very important to get a better understanding of why male care has evolved in mammals. Next, to understand why it has evolved so rarely compared to other groups, like fish and birds, we need to look more carefully at the various costs to the male of providing such care."

Robert Elwood, a professor emeritus of biological sciences at Queen's University Belfast, reminds that, for the majority of mammal males, fatherly care is literally not in their DNA.

He explained, "Staying with the female and young might appear to be a poor strategy for a male mammal since he is not normally important to the rearing of young because he cannot provide milk."

How all of this relates to humans, however, is a matter of debate. The researchers did not include humans in the study, but Elwood shared his thoughts about our species.

Read more at Discovery News

Bird Brains Packed with Neurons

Scientists have long been baffled by the smarts displayed by some birds with tiny brains.

But a new explanation may turn the term "bird brain" on its head: Birds have more densely packed neurons in their brains than other animals, contributing to cognitive ability on par with that of primates, researchers said on Monday.

A macaw's brain may be the size of a shelled walnut, far smaller than that of a macaque monkey -- which has a brain the size of a lemon -- but the parrot has many more neurons, or brain nerve cells, in its forebrain, a region crucial for intelligence, according to a study published in the Proceedings of the National Academy of Sciences.

The researchers were the first to systematically measure neurons in the brains of 20 bird species ranging in size from the tiny finch to the six-foot (1.8-meter) emu.

"For a long time having a 'bird brain' was considered to be a bad thing," said senior author Suzana Herculano-Houzel, a neuroscientist at Vanderbilt University. "Now it turns out that it should be a compliment."

Parrots and crows have cognitive abilities similar to those of primates, the study found.

The birds can make tools and use them to obtain food and solve other problems. They can also recognize themselves in mirrors and plan for future needs, cognitive capabilities only primates were previously thought to have enjoyed.

That is possible probably because the neurons in birds' brains are smaller and more densely packed than those in mammalian brains, the researchers said.

"We found that birds, especially songbirds and parrots, have surprisingly large numbers of neurons in their pallium: the part of the brain that corresponds to the cerebral cortex, which supports higher cognition functions such as planning for the future or finding patterns," Herculano-Houzel said.

"That explains why they exhibit levels of cognition at least as complex as primates."

Read more at Discovery News

Jun 13, 2016

Light-matter interplay probed: Physicists achieve quantum Hall state with light

Light and matter are typically viewed as distinct entities that follow their own, unique rules. Matter has mass and typically exhibits interactions with other matter, while light is massless and does not interact with itself. Yet, wave-particle duality tells us that matter and light both act sometimes like particles, and sometimes like waves.

Harnessing the shared wave nature of light and matter, researchers at the University of Chicago led by Neubauer Family Assistant Professor of Physics Jonathan Simon have used light to explore some of the most intriguing questions in the quantum mechanics of materials. The topic encompasses complex and non-intuitive phenomena that are often difficult to explain in non-technical language, but which carry important implications to specialists in the field.

In work published online June 6, 2016, in the journal Nature, Simon's group presents new experimental observations of a quantum Hall material near a singularity of curvature in space.

Quantum effects give rise to some of the most useful and promising properties of materials: they define standard units of measurement, give rise to superconductivity, and describe quantum computers. The quantum hall materials are one prominent example in which electrons are trapped in non-conducting circular orbits except at the edges of the material. There, electrons exhibit quantized resistance-free electrical conduction that is immune to disorder such as material impurities or surface defects.

Furthermore, electrons in quantum Hall materials do not transmit sound waves but instead have particle-like excitations, some of which are unlike any other particles ever discovered. Some of these materials also exhibit simultaneous quantum entanglement between millions of electrons, meaning that the electrons are so interconnected, the state of one instantly influences the state of all others. This combination of properties makes quantum Hall materials a promising platform for future quantum computation.

Researchers worldwide have spent the past 35 years delving into the mysteries of quantum Hall materials, but always in the same fundamental way. They use superconducting magnets to make very powerful magnetic fields and refrigerators to cool electronic samples to thousandths of a degree above absolute zero.

Trapping light...

In a new approach, Simon and his team demonstrated the creation of a quantum Hall material made up of light. "Using really good mirrors that are pointed at each other, we can trap light for a long time while it bounces back and forth many thousands of times between the mirrors," explained graduate student Nathan Schine.

In the UChicago experiment, photons travel back and forth between mirrors, while their side-to-side motion mimics the behavior of massive particles like electrons. To emulate a strong magnetic field, the researchers created a non-planar arrangement of four mirrors that makes the light twist as it completes a round trip. The twisting motion causes the photons to move like charged particles in a magnetic field, even though there is no actual magnet present.

"We make the photons spin, which leads to a force that has the same effect as a magnetic field," explained Schine. While the light is trapped, it behaves like the electrons in a quantum Hall material.

First, Simon's group demonstrated that they had a quantum Hall material of light. To do so, they shined infrared laser light at the mirrors. By varying the laser's frequency, Simon's team could map out precisely at which frequencies the laser was transmitted through the mirrors. These transmission frequencies, along with camera images of the transmitted light, gave a telltale signature of a quantum Hall state.

Next, the researchers took advantage of the precise control that advanced optical systems provide to place the photons in curved space, which has not been possible so far with electrons. In particular, they made the photons behave as if they resided on the surface of a cone.

...near a singularity

"We created a cone for light much like you might do by cutting a wedge of paper and taping the edges together," said postdoctoral fellow Ariel Sommer, also a co-author of the paper. "In this case, we imposed a three-fold symmetry on our light, which essentially divides the plane into three wedges and forces the light to repeat itself on each wedge."

The tip of a cone has infinite curvature--the singularity--so the researchers were able to study the effect of strong spatial curvature in a quantum Hall material. They observed that photons accumulated at the cone tip, confirming a previously untested theory of the quantum Hall effect in curved space.

Despite 20 years of interest, this is the first time an experiment has observed the behavior of quantum materials in curved space. "We are beginning to make our photons interact with each other," said Schine. "This opens up many possibilities, such as making crystalline or exotic quantum liquid states of light. We can then see how they respond to spatial curvature."

The researchers say this could be useful for characterizing a certain type of quantum computer that is built of quantum Hall materials.

Read more at Science Daily

Weird, water-oozing material could help quench thirst

After their nanorods were accidentally created when an experiment didn't go as planned, the researchers gave the microscopic, unplanned spawns of science a closer look.

Chemist Satish Nune was inspecting the solid, carbon-rich nanorods with a vapor analysis instrument when he noticed the nanorods mysteriously lost weight as humidity increased. Thinking the instrument had malfunctioned, Nune and his colleagues moved on to another tool, a high-powered microscope.

They jumped as they saw an unknown fluid unexpectedly appear between bunches of the tiny sticks and ooze out. Video recorded under the microscope is shaky at the beginning, as they quickly moved the view finder to capture the surprising event again.

The team at the Department of Energy's Pacific Northwest National Laboratory would go on to view the same phenomenon more than a dozen times. Immediately after expelling the fluid, the nanorods' weight decreased by about half, causing the researchers to scratch their heads even harder.

A paper published in Nature Nanotechnology describes the physical processes behind this spectacle, which turned out to be the first experimental viewing of a phenomenon theorized 20-some years ago. The discovery could lead to a large range of real-world applications, including low-energy water harvesting and purification for the developing world, and fabric that automatically pulls sweat away from the body and releases it as a vapor.

"Our unusual material behaves a bit like a sponge; it wrings itself out halfway before it's fully saturated with water," explained PNNL post-doctoral research associate David Lao, who manufactured the material.

"Now that we've gotten over the initial shock of this unforeseen behavior, we're imagining the many ways it could be harnessed to improve the quality of our lives," said PNNL engineer David Heldebrant, one of the paper's two corresponding authors.

"But before we can put these nanorods to good use, we need to be able to control and perfect their size and shape," added Nune, the paper's other corresponding author.

Expectations v. reality

Ordinarily, materials take on more water as the humidity around them increases. But these carbon-rich nanorods -- which the researchers mistakenly created while trying to fabricate magnetic nanowires -- suddenly expelled a large amount of water as the relative humidity inside the specimen holder reached anywhere between 50 and 80 percent.

Water expulsion can clearly be seen in the microscope video. Water is visible as a gray, cloudy haze -- and only emerges from where nanorods intersect. When the team went on to raise the humidity further, the nanorods' weight also increased, indicating they were taking on water again. It was also reversible, with water being ejected and later absorbed as humidity was gradually lowered back down.

The team was further intrigued. They couldn't think of any other material that takes on water at a low humidity and spontaneously releases it at a high humidity. So they dug through the canons of scientific literature to find an explanation.

Old theory, new evidence

They found a 2012 paper in the Journal of Physical Chemistry B that explained how, in certain situations where liquid is confined in a teeny-tiny space (roughly 1.5 nanometers wide), the liquid can spontaneously evaporate. And the authors of a 2013 paper in the (Journal of Chemical Physics described how water can condense into the confines of close hydrophobic materials, which do not play well with water, and quickly turn into vapor due to attractive forces between the surfaces of the two materials facing each other. The 2013 paper gave this phenomenon a very long, technical name: "solvent cavitation under solvo-phobic confinement."

These papers also noted the process was theorized as early as the 1990s by scientists examining crystallized proteins. Back then, scientists noticed they only saw water vapor surrounding hydrophobic sections of protein, while liquid water would surround other areas. The researchers proposed that there was some sort of process that enabled the water caught between hydrophobic protein sections to suddenly vaporize.

Armed with this knowledge, the PNNL team hypothesized water was condensing and forming a bridge between the nanorods, through a process known as capillary condensation. Next, they believe water between rods forms a curved cavity whose surface tension pulls the adjacent rods closer together. When two intersecting nanorods reach about 1.5 nanometers apart, the team reasoned, the water caught between them could be forced to quickly evaporate.

Putting it to good use

Though understanding the nanorods' unexpected behavior is a triumph in itself, the PNNL team also foresees a future where this phenomenon could also improve quality of life. They see their discovery as a potential humanitarian lifesaver, describing it as "a paradigm shift in water purification and separation," in their paper.

Theoretically, large quantities of the water-spitting nanomaterial could repeatedly take on and then eject collected water when a certain humidity level is reached. Such a system could be used in remote deserts, where it would collect water from the air and harvest it for human consumption.

Another vision is to create a membrane that takes on and later expels water as humidity changes. The membrane could be used in jacket fabrics and enable more comfortable outdoor adventures by removing sweat from inside a jacket and emitting it outside as a vapor.

Read more at Science Daily

It's not an illusion: Transforming infrared into visible light

Animated GIF of red laser impinging onto the appearing cluster, inducing a glow and the emission of a white-light laser.
Researchers have developed a compound that can transform near-infrared light into broadband white-light, offering a cheap, efficient means to produce visible light.

The emitted light is also exceedingly directional, a desirable quality for devices like microscopes that require high spatial resolution, or for applications with high throughput, such as projection systems.

Nils Wilhelm Rosemann and colleagues designed their compound of tin and sulfur, and with a diamondoid-like structure, then coating this scaffolding with organic ligands.

When a laser directs near-infrared light into the compound, the structure of the compound alters the wavelength of the light through a non-linear interaction process, producing light at wavelengths that are visible to the human eye.

The authors note that the warm, white-colored light that's emitted is very similar to a standard tungsten-halogen light source (2856 Kelvin), and can be adjusted based on levels of excitation via the laser.

This development could open up new routes for advanced directed illumination technologies, especially since the materials used in this system are cheap, readily available, and easily scalable.

From Science Daily

2,000-Year-Old Butter Found in Irish Bog

Turf cutters working in an Irish peat bog have unearthed a 2,000-year-old lump of butter, the Cavan County Museum announced.

Smelling like a strong cheese, the 22-pound chunk of waxy material was found 12 feet below the surface near the town of Drakerath, some 50 miles north of Dublin.

According to experts, the bog butter is still in excellent condition.

"Bogs are excellent preservative properties – low temperature, low oxygen and highly acidic environment," the museum said in a statement.

It is likely the butter was put in the peat bog as a gift to the gods rather than buried with the aim of preserving it.

Andy Halpin at the National Museum of Ireland, where the butter has been sent to be carbon dated and analyzed, said the creamy dairy product may never have been intended to be dug up.

A ritual burial appears more likely since the butter was not packed when it was interred at the site.

"These bogs in those times were inaccessible, mysterious places," Halpin told Press Association.

"It is at the juncture of three separate kingdoms, and politically it was like a no-man's-land -- that is where it all hangs together," he added.

The finding is not unusual. Hundreds of packages of butter, some placed inside wooden boxes, have been retrieved from Irish bogs, along with exceptionally well-preserved wooden objects, swords and ornaments.

Such preservation is produced by the bogs' unique chemistry. The peat-building Sphagnum moss grows over anything tipped into the bog, embedding the buried material in cold, acid and oxygen-free conditions that immobilize bacteria, preventing decomposition.

The newly found butter is still edible – theoretically.

"But we wouldn't advice tasting it," Halpin said.

From Discovery News

Ancient Cities in Cambodia Revealed by Lasers

Angkor Wat is seen at sunset. The UNESCO World Heritage site, and the largest religious monument in the world, has medieval cities hidden nearby, new laser analysis reveals.
Unprecedented new details of medieval cities hidden under jungle in Cambodia near Angkor Wat have been revealed using lasers, archaeologists said Sunday, shedding new light on the civilisation behind the world's largest religious complex.

While the research has been going on for several years, the new findings uncover the sheer scale of the Khmer Empire's urban sprawl and temple complexes to be significantly bigger than was previously thought.

The research, drawing on airborne laser scanning technology known as lidar, will be unveiled in full at the Royal Geographic Society in London on Monday by Australian archaeologist Damian Evans.

"We always imagined that their great cities surrounded the monuments in antiquity," Evans told AFP.

"But now we can see them with incredible precision and detail, in some places for the very first time, but in most places where we already had a vague idea that cities must be there," he added.

Angkor Wat, a UNESCO World Heritage site seen as among the most important in southeast Asia, is considered one of the ancient wonders of the world.

It was constructed from the early to mid 1100s by King Suryavarman II at the height of the Khmer Empire's political and military power and was among the largest pre-industrial cities in the world.

But scholars had long believed there was far more to the empire than just the Angkor complex.

The huge tranch of new data builds on scans that were made in 2012 that confirmed the existence of Mahendraparvata, an ancient temple city near Angkor Wat.

But it was only when the results of a larger survey in 2015 were analysed that the sheer scale of the new settlements became apparent.

To create the maps, archaeologists mounted a special laser on the underneath of a helicopter which scans the area and is able to see through obstructions like trees and vegetation.

Much of the cities surrounding the famed stone temples of the Khmer Empire, Evans explained, were made of wood and thatch which has long rotted away.

"The lidar quite suddenly revealed an entire cityscape there with astonishing complexity," he said.

"It turned out we'd been walking and flying right over the top of this stuff for ten years and not even noticing it because of the vegetation."

Among the new scans already published are a detailed map of a huge city complex surrounding the stone temple known as Preah Khan of Kompong Svay, a series of iron smelting sites dating back to the Angkor era and new information on the complex system of waterways that kept the region running.

The new data also maps out the full extent of Mahendraparvata, information that will make future digs much more accurate and less time consuming.

"What we had was basically a scatter of disconnected points on the map denoting temple sites. Now it's like having a detailed street map of the entire city," Evans said.

Further maps will be published in the coming months, he added.

Read more at Discovery News

Jun 12, 2016

Many with migraines have vitamin deficiencies, says study

A high percentage of children, teens and young adults with migraines appear to have mild deficiencies in vitamin D, riboflavin and coenzyme Q10, say researchers.
A high percentage of children, teens and young adults with migraines appear to have mild deficiencies in vitamin D, riboflavin and coenzyme Q10 -- a vitamin-like substance found in every cell of the body that is used to produce energy for cell growth and maintenance.

These deficiencies may be involved in patients who experience migraines, but that is unclear based on existing studies.

"Further studies are needed to elucidate whether vitamin supplementation is effective in migraine patients in general, and whether patients with mild deficiency are more likely to benefit from supplementation," says Suzanne Hagler, MD, a Headache Medicine fellow in the division of Neurology at Cincinnati Children's Hospital Medical Center and lead author of the study.

Dr. Hagler and colleagues at Cincinnati Children's conducted the study among patients at the Cincinnati Children's Headache Center. She will present her findings at 9:55 am Pacific time June 10, 2016 at the 58th Annual Scientific Meeting of the American Headache Society in San Diego.

Dr. Hagler's study drew from a database that included patients with migraines who, according to Headache Center practice, had baseline blood levels checked for vitamin D, riboflavin, coenzyme Q10 and folate, all of which were implicated in migraines, to some degree, by previous and sometimes conflicting studies. Many were put on preventive migraine medications and received vitamin supplementation, if levels were low. Because few received vitamins alone, the researchers were unable to determine vitamin effectiveness in preventing migraines.

She found that girls and young woman were more likely than boys and young men to have coenzyme Q10 deficiencies at baseline. Boys and young men were more likely to have vitamin D deficiency. It was unclear whether there were folate deficiencies. Patients with chronic migraines were more likely to have coenzyme Q10 and riboflavin deficiencies than those with episodic migraines.

Previous studies have indicated that certain vitamins and vitamin deficiencies may be important in the migraine process. Studies using vitamins to prevent migraines, however, have had conflicting success.

From Science Daily

X-ray snapshot of butterfly wings reveals underlying physics of color

A team of physicists that visualized the internal nanostructure of an intact butterfly wing has discovered two physical attributes that make those structures so bright and colorful.
A team of physicists that visualized the internal nanostructure of an intact butterfly wing has discovered two physical attributes that make those structures so bright and colorful.

"Over millions of years, butterflies have evolved sophisticated cellular mechanisms to grow brightly colored structures, normally for the purpose of camouflage as well as mating," says Oleg Shpyrko, an associate professor of physics at UC San Diego, who headed the research effort. "It's been known for a century that the wings of these beautiful creatures contain what are called photonic crystals, which can reflect light of only a particular color."

But exactly how these complex optical structures are assembled in a way that make them so bright and colorful remained a mystery. In an effort to answer that question, Shpyrko and Andrej Singer, a postdoctoral researcher in his laboratory, went to the Advanced Photon Source at the Argonne National Laboratory in Illinois, which produces coherent x-rays very much like an optical laser

By combining these laser-like x-rays with an advanced imaging technique called "ptychography," the UC San Diego physicists, in collaboration with physicists at Yale University and the Argonne National Laboratory, developed a new microscopy method to visualize the internal nanostructure of the tiny "scales" that make up the butterfly wing without the need to cut them apart.

The researchers report in the current issue of the journal Science Advances that their examination of the scales of the Emperor of India butterfly, Teinopalpus imperialis, revealed that these tiny wing structures consist of "highly oriented" photonic crystals.

"This explains why the scales appear to have a single color," says Singer, the first author of the paper. "We also found through careful study of the high-resolution micrographs tiny crystal irregularities that may enhance light-scattering properties, making the butterfly wings appear brighter."

These crystal dislocations or defects occur, the researchers say, when an otherwise perfectly periodic crystal lattice slips by one row of atoms. "Defects may have a negative connotation, but they are actually very useful in improving materials," explains Singer. "For example, blacksmiths have learned over centuries how to purposefully induce defects into metals to make them stronger. 'Defect engineering' is also a focus for many research teams and companies working in the semiconductor field. In photonic crystals, defects can enhance light-scattering properties through an effect called light localization."

"In the evolution of butterfly wings," he adds, "it appears nature learned how to engineer these defects on purpose."

From Science Daily