Aug 18, 2016

Recent connection between North and South America reaffirmed

A cargo ship in the Panama Canal traverses volcanic rocks that helped form the Isthmus of Panama.
Long ago, one great ocean flowed between North and South America. When the narrow Isthmus of Panama joined the continents about 3 million years ago, it also separated the Atlantic from the Pacific Ocean. If this took place millions of years earlier, as recently asserted by some, the implications for both land and sea life would be revolutionary. Aaron O'Dea, staff scientist at the Smithsonian Tropical Research Institute (STRI), and colleagues writing in Science Advances firmly set the date at 2.8 million years ago.

"Recent scientific publications proposing the isolation of the two oceans between 23 to 6 million years ago rocked the generally held model of the continental connection to its foundations," said Jeremy Jackson, emeritus staff scientist at the Smithsonian. "O'Dea and his team set out to reevaluate in unprecedented, rigorous detail, all of the available lines of evidence -- geologic, oceanographic, genetic and ecological data and the analyses that bear on the question of when the Isthmus formed."

"The timing of the connection between continents and the isolation of the Pacific and Atlantic oceans is important for so many reasons," O'Dea said. "Estimates of rates of evolutionary change, models of global oceans, the origin of modern-day animals and plants of the Americas and why Caribbean reefs became established all depend upon knowing how and when the isthmus formed."

The team of researchers from 23 institutions, including nine current or emeritus staff scientists from STRI and the Smithsonian's National Museum of Natural History and 13 current or previous Smithsonian post-doctoral fellows concluded that records from marine and terrestrial fossils, volcanic and marine rocks and the genes of marine animals split by the formation of the Isthmus all tell the same story. Three key pieces of evidence defined when the land bridge was finally in place:

  • Analysis of the family trees of shallow-water marine animals such as fish and sand dollars from the Pacific and Caribbean (Atlantic) sides of the isthmus show genetic mixing until after 3.2 million years ago.
  • Surface waters from the Pacific and Caribbean mixed until about 2.8 million years ago, as seen in deep-ocean sediments.
  • Massive migrations of land animals between North and South America began sometime before 2.7 million years ago.

The first paper to propose an earlier connection, published by Camilo Montes, professor at the Universidad de los Andes, and STRI staff scientist Carlos Jaramillo in 2015, asserted that tiny particles called zircons found in northern Colombia arrived there 15 million years ago via rivers from the Panama Arc along a land bridge. The authors of the new paper reveal that, in fact, there are several possible sources for these zircons, all of which require less convoluted travel to arrive at their resting place in the Magdalena basin.

The second paper to propose an earlier isthmus by Christine Bacon, post-doctoral fellow at the University of Gothenburg, suggested that molecular data from terrestrial animals and plants corresponded with geographic splits in marine animals, assuming the correspondence must have been due to a land bridge. The new study questions their use of a universal rate of evolution -- "different species evolve at different rates" Harilaos Lessios, a coauthor, said. They also question their use of genetic splits for land animals as evidence of the continental connection because "a land bridge would not cause genetic divergence, but would, on the contrary, allow greater genetic mixing between the continents."

In addition, the new paper mentions that Bacon et al.'s study omitted several important published genetic analyses, which skewed their results and when included, eliminate the main line of evidence that marine and terrestrial events coincided.

Read more at Science Daily

NASA prepares to launch first U.S. Asteroid sample return mission

OSIRIS-REx will travel to near-Earth asteroid Benn on a sample return mission.
NASA is preparing to launch its first mission to return a sample of an asteroid to Earth. The mission will help scientists investigate how planets formed and how life began, as well as improve our understanding of asteroids that could impact Earth.

The Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer (OSIRIS-REx) spacecraft will travel to the near-Earth asteroid Bennu and bring a sample back to Earth for intensive study. Launch is scheduled for 7:05 p.m. EDT Thursday, Sept. 8 from Cape Canaveral Air Force Station in Florida.

"This mission exemplifies our nation's quest to boldly go and study our solar system and beyond to better understand the universe and our place in it," said Geoff Yoder, acting associate administrator for the agency's Science Mission Directorate in Washington. "NASA science is the greatest engine of scientific discovery on the planet and OSIRIS-REx embodies our directorate's goal to innovate, explore, discover, and inspire."

The 4,650-pound (2,110-kilogram) fully-fueled spacecraft will launch aboard an Atlas V 411 rocket during a 34-day launch period that begins Sept. 8, and reach its asteroid target in 2018. After a careful survey of Bennu to characterize the asteroid and locate the most promising sample sites, OSIRIS-REx will collect between 2 and 70 ounces (about 60 to 2,000 grams) of surface material with its robotic arm and return the sample to Earth via a detachable capsule in 2023.

"The launch of OSIRIS-REx is the beginning a seven-year journey to return pristine samples from asteroid Bennu," said OSIRIS-REx Principal Investigator Dante Lauretta of the University of Arizona, Tucson. "The team has built an amazing spacecraft, and we are well-equipped to investigate Bennu and return with our scientific treasure."

OSIRIS-REx has five instruments to explore Bennu:

  • OSIRIS-REx Camera Suite (OCAMS) -- A system consisting of three cameras provided by the University of Arizona, Tucson, will observe Bennu and provide global imaging, sample site imaging, and will witness the sampling event.
  • OSIRIS-REx Laser Altimeter (OLA) -- A scanning LIDAR (Light Detection and Ranging) contributed by the Canadian Space Agency will be used to measure the distance between the spacecraft and Bennu's surface, and will map the shape of the asteroid.
  • OSIRIS-REx Thermal Emission Spectrometer (OTES) -- An instrument provided by Arizona State University in Tempe that will investigate mineral abundances and provide temperature information with observations in the thermal infrared spectrum.
  • OSIRIS-REx Visible and Infrared Spectrometer (OVIRS) -- An instrument provided by NASA's Goddard Space Flight Center in Greenbelt, Maryland and designed to measure visible and infrared light from Bennu to identify mineral and organic material.
  • Regolith X-ray Imaging Spectrometer (REXIS) -- A student experiment provided by the Massachusetts Institute of Technology (MIT) and Harvard University in Cambridge, which will observe the X-ray spectrum to identify chemical elements on Bennu's surface and their abundances.

Additionally, the spacecraft has two systems that will enable the sample collection and return:

  • Touch-And-Go Sample Acquisition Mechanism (TAGSAM) -- An articulated robotic arm with a sampler head, provided by Lockheed Martin Space Systems in Denver, to collect a sample of Bennu's surface.
  • OSIRIS-REx Sample Return Capsule (SRC) -- A capsule with a heat shield and parachutes in which the spacecraft will return the asteroid sample to Earth, provided by Lockheed Martin.

"Our upcoming launch is the culmination of a tremendous amount of effort from an extremely dedicated team of scientists, engineers, technicians, finance and support personnel," said OSIRIS-REx Project Manager Mike Donnelly at Goddard. "I'm incredibly proud of this team and look forward to launching the mission's journey to Bennu and back."

Read more at Science Daily

Oxygen on 'Exo-Venus' Wouldn't Mean Life

When studying an alien world orbiting another star, one would think astronomers would be thrilled to detect oxygen in its atmosphere. Oxygen could mean life, after all. But in the case of GJ 1132b, which orbits a star 39 light-years away, the detection of oxygen would mean the exact opposite.

The exoplanet, which can be thought of as an "exo-Venus," is, as you'd expect, a hellish world. It has a very compact orbit around its star, at a distance of only 1.4 million miles, ensuring that it's constantly baked by the star's powerful radiation.

When it was discovered last year, GJ 1132b became a fascination for astronomers. Despite its rather extreme orbit, it seems to retain an atmosphere. This is contrary to what is expected; constant heating from the star and powerful stellar winds should bake-off the atmosphere very quickly, leaving a molten, barren planetary husk behind.

Now astronomers are trying to work out whether its atmosphere is thick, or whether it's thin and wispy. Starting with the assumption that GJ 1132b formed with a water-rich atmosphere, astronomer Laura Schaefer, of the Harvard-Smithsonian Center for Astrophysics (CfA), and her team believe the latter is most likely.

In that scenario, the water molecules (H2O) on the exoplanet would have been broken down by the powerful ultraviolet light, releasing the hydrogen atoms to space, leaving the heavier oxygen behind as a thin atmosphere.

To test this idea, we need more powerful observatories to analyze the world's spectroscopic signature to see if its atmosphere does indeed contain oxygen. NASA's James Webb Space Telescope, which is scheduled for launch in 2018, could be used to detect this atmospheric oxygen.

"On cooler planets, oxygen could be a sign of alien life and habitability. But on a hot planet like GJ 1132b, it's a sign of the exact opposite -- a planet that's being baked and sterilized," said Schaefer in a CfA statement.

Early in GJ 1132b's atmospheric evolution, its water vapor content would have acted as a powerful greenhouse gas, amplifying the star's already powerful heating. This would have ensured that the surface of the planet remained in a molten state for millions of years. Although the magma would have absorbed a little of the oxygen, and more would have been vented into space, enough would linger that could be detected with advanced astronomical studies.

"This planet might be the first time we detect oxygen on a rocky planet outside the solar system," said Robin Wordsworth, of the Harvard Paulson School of Engineering and Applied Sciences.

Read more at Discovery News

Ancient Civilization in Mexico Bred, Ate Rabbits

Shown is an illustration of the leporid sculpture from the Oztoyahualco compound of Teotihuacan.
Native people living in the ancient city of Teotihuacan, now a World Heritage site located in modern-day Mexico, likely bred rabbits to eat and used their bones for tools, researchers said Wednesday.

The study in the open-access journal PLOS ONE represents one of the first known examples of small mammal breeding in an indigenous culture that existed from the first to the seventh century AD.

"Because no large mammals such as goats, cows or horses were available for domestication in pre-Hispanic Mexico, many assume that Native Americans did not have as intensive human-animal relationships as did societies of the Old World," said lead author Andrew Somerville, a researcher at the University of California, San Diego.

"Our results suggest that citizens of the ancient city of Teotihuacan engaged in relationships with smaller and more diverse fauna, such as rabbits and jackrabbits, and that these may have been just as important as relationships with larger animals."

Many archaeological excavations have been done at the site, which covers eight square miles (20 square kilometers) and was home to some 100,000 residents, making it the largest urban center of its time, said the study.

Analyses have shown that wild rabbits were among the most common mammals there, making up 48 percent of all identified fauna remains near a residential compound called Oztoyahualco.

Evidence of animal butchering was found in several rooms, where "high soil phosphate levels in the floor suggest the presence of disintegrated fecal matter or blood from butchering," said the study.

Researchers found obsidian blades, multiple rabbit foot bones and low stone walls that may have been used as pens for keeping rabbits.

There is also "a unique stone sculpture of a rabbit" in a nearby public courtyard.

The study said many of the rabbits were likely acquired through the practice of garden-hunting.

Villagers would have nabbed rabbits from fields where squash, maize and beans were grown. Similar practices were seen in other pre-Hispanic societies of the era.

But saving their crops was not the only reason for the high number of rabbit remains, the study said.

Stable carbon and oxygen isotope analysis of 134 rabbit and hare bone specimens from the ancient city and 13 modern wild specimens from central Mexico showed that those inside the compound were eating more human-farmed crops, such as maize, suggesting that people were feeding them and raising them in Oztoyahualco.

Read more at Discovery News

Aug 17, 2016

Snake eyes: New insights into visual adaptations

Tree viper / Atheris squamigera.
Snakes have adapted their vision to hunt their prey day or night. For example, snakes that need good eyesight to hunt during the day have eye lenses that act as sunglasses, filtering out ultraviolet light and sharpening their vision while nocturnal snakes have lenses that allow ultraviolet light through, helping them to see in the dark.

New insights into the relationship between ultraviolet (UV) filters and hunting methods in snakes is one of the findings of the first major study of visual pigment genes and lenses in snakes -- published in the advanced online edition of Molecular Biology and Evolution.

The new research was an international collaboration between snake biologists and vision experts led by the David Gower and included fellow Natural History Museum researchers Bruno Simões and Filipa Sampaio. Much of the research, including most of the DNA analyses, was carried out in the Museum's laboratories.

Scientists have long known that snakes have highly variable sets of rods and cones -- the specialised cells in the retina that an animal uses to detect light. But until now, most modern studies of vision in vertebrates (animals with a backbone) have concentrated on mammals, birds and fish.

To see in different colors, animals use visual pigments in their rods and cones that are sensitive to different wavelengths of light. The researchers examined the genes involved in producing the pigments from a broad genomic survey of 69 different species of snakes. What they found was as the genes vary from species to species so does the exact molecular structure of the pigments and the wavelengths of light they absorb.

The new research discovered that most snakes possess three visual pigments and are likely dichromatic in daylight -- seeing two primary colours rather than the three that most humans see.

However, it also discovered that snake visual pigment genes have undergone a great amount of adaptation, including many changes to the wavelengths of light that the pigments are sensitive to, in order to suit the diversity of lifestyles that snakes have evolved.

Most snakes examined in the new study are sensitive to UV light, which likely allows them to see well in low light conditions. For light to reach the retina and be absorbed by the pigments, it first travels through the lens of the eye. Snakes with UV-sensitive visual pigments therefore have lenses that let UV light though.

In contrast, the research showed that those snakes that rely on their eyesight to hunt in the daytime, such as the gliding golden tree snake Chrysopelea ornata and the Monypellier snake Malpolon monspessulanus, have lenses that block UV light. As well as perhaps helping to protect their eyes from damage, this likely helps sharpen their sight -- in the same way that skiers' yellow goggles cut out some blue light and improve contrast.

Moreover, these snakes with UV-filtering lenses have tuned the pigments in their retina so that they are no longer sensitive to the short UV light, but absorb longer wavelengths.

Read more at Science Daily

Tree-rings reveal secret clocks that could reset key dates across the ancient world

Scholars believe that intense solar storms caused major bursts of radiation to strike the Earth in 775 and 994AD, which resulted in distinct spikes in the concentration of radiocarbon in trees growing at that time.
Oxford University researchers say that trees which grew during intense radiation bursts in the past have 'time-markers' in their tree-rings that could help archaeologists date events from thousands of years ago. In a new paper, the authors explain how harvesting such data could revolutionise the study of ancient civilisations such as the Egyptian and Mayan worlds. Until now scholars have had only vague evidence for dating when events happened during the earliest periods of civilisation, with estimates being within hundreds of years. However, the unusually high levels of the radioactive isotope carbon-14 found in tree-rings laid down during the radiation bursts could help reliably pinpoint dates. The distinct spikes act as time-markers like secret clocks contained in timber, papyri, baskets made from living plants or other organic materials, says the paper published in the Royal Society Journal Proceedings A.

Scholars believe that intense solar storms caused major bursts of radiation to strike Earth in 775 and 994AD, which resulted in distinct spikes in the concentration of radiocarbon in trees growing at that time. The events are precisely datable because the tree-rings belong to archives in which the growth year of each tree-ring is exactly known. In the new research, the authors outline how they could detect similar spikes elsewhere within the thousands of years of available tree-ring material from across the world. They say even a handful of these time-markers could allow them to piece together a reliable dating framework for important civilisations. The crucial point is that the time-markers will also be present in every living plant or tree that grew at the time of a radiation surge, including in the timber used in ancient buildings or other artefacts fashioned from the plants. The paper suggests that the existing tree-ring data are likely to reveal other radiocarbon surges in particular years. The problem, however, is that the tree-ring data is only available in blocks of decades rather than year by year. The paper proposes a cutting-edge mathematical method to filter out particular years within such a block when 'change points' in radiocarbon levels occurred. It also adds that it is currently unclear how regularly Earth has been hit by such intense bursts of radiation, and what the precise magnitude of the events might have been so finding new spikes will also help us understand past solar activity.

Currently, archaeologists have to rely on relatively sparse evidence for dating the history of Western civilisation before 763 BCE, with Chinese history also only widely agreed from 841 BCE. For example, they depend on ancient records of rare astronomical phenomena, such as the solar eclipse during the ninth year of Ashur Dan III of Assyria, to determine the age of historical events. In the absence of such records, standard radiocarbon measurements provide the best estimates, but these are still often only accurate to within 200 to 300 calendar years. If the radiocarbon spikes in the tree-ring data were also found in archaeological items attributable to specific historical periods, the information could be used to anchor exactly when events occurred, says the paper.

Read more at Science Daily

How we escaped the Big Bang: New theory on moving through time

In her research published in The Royal Society Dr Vaccaro says T violation, or a violation of time reversal (T) symmetry, is forcing the universe and us in it, into the future.
Associate Professor Dr Joan Vaccaro, of Griffith's Centre for Quantum Dynamics, has solved an anomaly of conventional physics and shown that a mysterious effect called 'T violation' could be the origin of time evolution and conservation laws.

"I begin by breaking the rules of physics, which is rather bold I have to admit, but I wanted to understand time better and conventional physics can't do that," Dr Vaccaro says.

"I do get conventional physics in the end though. This means that the rules I break are not fundamental. It also means that I can see why the universe has those rules. And I can also see why the universe advances in time."

In her research published in The Royal Society Dr Vaccaro says T violation, or a violation of time reversal (T) symmetry, is forcing the universe and us in it, into the future.

"If T violation wasn't involved we wouldn't advance in time and we'd be stuck at the Big Bang, so this shows how we escaped the Big Bang.

"I found the mechanism that forces us to go to the future, the reason why you get old and the reason why we advance in time." "The universe must be symmetric in time and space overall. But we know that there appears to be a preferred direction in time because we are incessantly getting older not younger."

The anomaly Dr Vaccaro solves involves two things not accounted for in in conventional physical theories -- the direction of time, and the behaviour of the mesons (which decay differently if time went in the opposite direction).

Experiments show that the behaviour of mesons depends on the direction of time; in particular, if the direction of time was changed then their behaviour would also," she says.

"Conventional physical theories can accommodate only one direction of time and one kind of meson behaviour, and so they are asymmetric in this regard. But the problem is that the universe cannot be asymmetric overall.

"This means that physical theories must be symmetric in time. To be symmetric in time they would need to accommodate both directions of time and both meson behaviours. This is the anomaly in physics that I am attempting to solve."

Dr Vaccaro is presenting her work at the Soapbox Science event held in Brisbane as part of National Science Week, titled "The meaning of time: why the universe didn't stay put at the big bang and how it is 'now' and no other time."

Without any T violation the theory gives a very strange universe. An object like a cup can be placed in time just like it is in space.

"It just exists at one place in space and one point in time. There is nothing unusual about being at one place in space, but existing at one point in time means the object would come into existence only at that point in time and then disappear immediately.

"This means that conservation of matter would be violated. It also means that there would be no evolution in time. People would only exist for a single point in time -- they would not experience a "flow of time."

Read more at Science Daily

Oldest Slab of Seafloor Found in Mediterranean

What may be the oldest patch of undisturbed oceanic crust on Earth has recently been identified by an Israeli scientist. Roi Granot, a professor at Ben Gurion University of the Nevev, estimates that the crust, which lies deep beneath the eastern Mediterranean Sea, may be 340 million years old -- making it 150 million years oldedr than the previous record holder.

Compared to continental crust, which can be billions of years old, oceanic crust is relatively young: It forms when hot magma wells up at oceanic ridges, and spreads slowly across the ocean floor, only to be recycled back into Earth's mantle because of its high density, before ultimately rising again as new magma.

The oldest piece of oceanic crust found to this point, off the east coast of Japan, is estimated at 190 million years old -- although a rare example of ocean crust being forced upward and onto land has been found in Greenland, part of a 3.5 billion-year-old chunk that is the oldest piece of Earth's crust ever found.

As part of an effort to study the nature and age of the crust underlying the eastern Mediterranean, Granot and a team of researchers conducted four research cruises over the course of two years, crossing the area between Turkey and Egypt and towing sensors to search for magnetic signals. Such signals are a result of the magnetization of minerals in newly forming rocks when magma at a mid-ocean ridge axis cools; those magnetic minerals align themselves with the direction of Earth's magnetic field, and flip each time the field does.

"Changes in the magnetic field's orientation over time are recorded in the ocean floors, creating a unique barcode that provides a time stamp for crust formation," Granot said in a press release.

After two years of searching, Granot's efforts bore fruit, when his data revealed a series of magnetic stripes.

"Here I am in the middle of the eastern Mediterranean and I see this beautiful feature that crosses the entire sea, from north to south," Granot told New Scientist. "That feature can only be created by oceanic crust."

By comparing the signals with modeling of plate tectonics, Granot determined that the roughly 60,000-square-mile piece of crust was approximately 340 million years old. That would place it at roughly the time that Earth's landmasses were combining to form the super-continent Pangaea, and therefore, may be a remnant of the ancient Tethys Sea. If so, it would suggest that that ocean formed some 50 million years earlier than previously thought -- or, Granot proposed, his discovery might be part of some other, unknown, ocean floor.

From Discovery News

'Ultimate Pokémon' Squirrel Evades the Eyes of Science

An illustration from 1898 shows the Zenkerella insignis.
They know it exists, thanks to eyewitness accounts and a handful of bodies found over time, but a squirrel in central Africa continues to elude biologists, who have yet to see one alive. Three new bodies, however, have at least given scientists a chance to sample its DNA for the first time.

The squirrel, Zenkerella insignis, a rodent with scales at the base of its tail, has been so successful at staying off the grid that only 14 of its specimens are curated in museums.

"Zenkerella could be seen as the ultimate Pokémon that scientists have still not been able to find or catch alive," said Erik Seiffert, lead author of a new study in the journal Peer J on the little-seen rodent, in a statement.

"After all," added the professor of cell and neurobiology at the University of Southern California, "it probably only shows up in the middle of the night, deep in the jungles of central Africa, and might spend most of its time way up in tall trees where it would be particularly hard to see."

The second of three new specimens of Zenkerella insignis was found by hunters near the village of Ureca on Bioko, an island off the west coast of Africa.
But genetic testing can tell scientists much about the critter, even if they can't spot one alive.

Cheek swabs taken from three recent specimens of the creature allowed Seiffert and his colleagues to compare Zenkerella's DNA against other rodent DNA sequences, to learn more about the mysterious animal's place in the taxonomic tree.

Having traditionally been lumped in with two other "scaly-tailed squirrels" in the Anomaluridae family, thanks to brain and jaw similarities, the researchers argue that Zenkerella actually belongs under its own, newly named family Zenkerellidae.

At issue is the ability to glide. The other two Anomaluridae squirrels -- Anomalurus and Idiurus -- have webbing between their legs and elbows, which allows them to glide between trees. But Zenkerella has no such webbing.

According to the researchers, grouping the three squirrels together, implied "that either the Zenkerella lineage lost its gliding adaptations, or that Anomalurus and Idiurus evolved theirs independently."

The scientists say their data shows that gliding only evolved once among the Anomaluridae, without subsequent loss of the ability, making Zenkerella a distant cousin to Anomalurus and Idiurus and worthy of a different family.

Read more at Discovery News

Aug 16, 2016

Van Allen probes catch rare glimpse of supercharged radiation belt

This is an artist concept of accelerated electrons circulating in Earth's Van Allen radiation belts.
Our planet is nestled in the center of two immense, concentric doughnuts of powerful radiation: the Van Allen radiation belts, which harbor swarms of charged particles that are trapped by Earth's magnetic field. On March 17, 2015, an interplanetary shock -- a shockwave created by the driving force of a coronal mass ejection, or CME, from the sun -- struck Earth's magnetic field, called the magnetosphere, triggering the greatest geomagnetic storm of the preceding decade. And NASA's Van Allen Probes were there to watch the effects on the radiation belts.

One of the most common forms of space weather, a geomagnetic storm describes any event in which the magnetosphere is suddenly, temporarily disturbed. Such an event can also lead to change in the radiation belts surrounding Earth, but researchers have seldom been able to observe what happens. But on the day of the March 2015 geomagnetic storm, one of the Van Allen Probes was orbiting right through the belts, providing unprecedentedly high-resolution data from a rarely witnessed phenomenon. A paper on these observations was published in the Journal of Geophysical Research on Aug. 15, 2016.

Researchers want to study the complex space environment around Earth because the radiation and energy there can impact our satellites in a wide variety of ways -- from interrupting onboard electronics to increasing frictional drag to disrupting communications and navigation signals.

"We study radiation belts because they pose a hazard to spacecraft and astronauts," said David Sibeck, the Van Allen Probes mission scientist at NASA's Goddard Space Flight Center in Greenbelt, Maryland, who was not involved with the paper. "If you knew how bad the radiation could get, you would build a better spacecraft to accommodate that."

Studying the radiation belts is one part of our efforts to monitor, study and understand space weather. NASA launched the twin Van Allen Probes in 2012 to understand the fundamental physical processes that create this harsh environment so that scientists can develop better models of the radiation belts. These spacecraft were specifically designed to withstand the constant bombardment of radiation in this area and to continue to collect data even under the most intense conditions. A set of observations on how the radiation belts respond to a significant space weather storm, from this harsh space environment, is a goldmine.

The recent research describes what happened: The March 2015 storm was initiated by an interplanetary shock hurtling toward Earth -- a giant shockwave in space set off by a CME, much like a tsunami is triggered by an earthquake.

Swelling and shrinking in response to such events and solar radiation, the Van Allen belts are highly dynamic structures within our planet's magnetosphere. Sometimes, changing conditions in near-Earth space can energize electrons in these ever-changing regions. Scientists don't yet know whether energization events driven by interplanetary shocks are common. Regardless, the effects of interplanetary shocks are highly localized events -- meaning if a spacecraft is not precisely in the right place when a shock hits, it won't register the event at all. In this case, only one of the Van Allen Probes was in the proper position, deep within the magnetosphere -- but it was able to send back key information.

The spacecraft measured a sudden pulse of electrons energized to extreme speeds -- nearly as fast as the speed of light -- as the shock slammed the outer radiation belt. This population of electrons was short-lived, and their energy dissipated within minutes. But five days later, long after other processes from the storm had died down, the Van Allen Probes detected an increased number of even higher energy electrons. Such an increase so much later is a testament to the unique energization processes following the storm.

"The shock injected -- meaning it pushed -- electrons from outer regions of the magnetosphere deep inside the belt, and in that process, the electrons gained energy," said Shri Kanekal, the deputy mission scientist for the Van Allen Probes at Goddard and the leading author of a paper on these results.

Researchers can now incorporate this example into what they already know about how electrons behave in the belts, in order to try to understand what happened in this case -- and better map out the space weather processes there. There are multiple ways electrons in the radiation belts can be energized or accelerated: radially, locally or by way of a shock. In radial acceleration, electrons are carried by low-frequency waves towards Earth. Local acceleration describes the process of electrons gaining energy from relatively higher frequency waves as the electrons orbit Earth. And finally, during shock acceleration, a strong interplanetary shock compresses the magnetosphere suddenly, creating large electric fields that rapidly energize electrons.

Scientists study the different processes to understand what role each process plays in energizing particles in the magnetosphere. Perhaps these mechanisms occur in combination, or maybe just one at a time. Answering this question remains a major goal in the study of radiation belts -- a difficult task considering the serendipitous nature of the data collection, particularly in regard to shock acceleration.

Additionally, the degree of electron energization depends on the process that energizes them. One can liken the process of shock acceleration, as observed by the Van Allen Probe, to pushing a swing.

"Think of 'pushing' as the phenomenon that's increasing the energy," Kanekal said. "The more you push a swing, the higher it goes." And the faster electrons will move after a shock.

In this case, those extra pushes likely led to the second peak in high-energy electrons. While electromagnetic waves from the shock lingered in the magnetosphere, they continued to raise the electrons' energy. The stronger the storm, the longer such waves persist. Following the March 2015 storm, resulting electromagnetic waves lasted several days. The result: a peak in electron energy measured by the Van Allen Probe five days later.

This March 2015 geomagnetic storm was one of the strongest yet of the decade, but it pales in comparison to some earlier storms. A storm during March 1991 was so strong that it produced long-lived, energized electrons that remained within the radiation belts for multiple years. With luck, the Van Allen Probes may be in the right position in their orbit to observe the radiation belt response to more geomagnetic storms in the future. As scientists gather data from different events, they can compare and contrast them, ultimately helping to create robust models of the little-understood processes occurring in these giant belts.

Read more at Science Daily

Piranhas With Human-Like Teeth Found in Michigan Lakes

Smile! Pacus use their disturbingly human-like teeth for cracking open seeds and nuts.
A South American fish with uncannily human-like chompers has been unexpectedly showing up on Michigan anglers' hooks.

The fish are red-bellied pacus (Piaractus brachypomus) and are piranha relatives, though their diet is mostly vegetarian. Pacus are popular with aquarium owners for their unusual square teeth that look remarkably human —rather disturbingly so, in fact. But recently, pacus have been sighted in places where they shouldn't be: Lake St. Clair and Port Huron in southeastern Michigan, where three pacus were caught during the month of July.

The pacus were almost certainly introduced into the lakes by former owners who kept them as pets, according to a statement released Aug. 9 by the Michigan Department of Natural Resources (DNR).

Pacus are native to the Amazon and Orinoco river basins and flood plains. Their flattened bodies resemble those of their sharp-toothed piranha cousins, but their own distinctive teeth are used for crushing seeds and nuts. Pacus can grow to be about 35 inches (89 centimeters) in length, and pet owners may be dismayed to find that their exotic pet can outgrow its tank, which can prompt them to release the fish in the wild, according to the DNR.

Warm temperatures are vital to the pacus' survival, so they are unlikely to become established as an invasive species in Michigan's seasonally cold waters. However, releasing pets in the wild is not only harmful to the animals and likely to result in their death, but could have severe implications for native wildlife and ecosystems, DNR officials said in the statement.

Pacus have been found in Michigan waters before, but this is the first time that people have caught three of them in one week, according to Nick Popoff, a biologist with the Fisheries Division at the DNR. Popoff told Live Science that it's possible the three fish came from a single tank that was dumped in a public access site.

"Pacus' temperature requirements are tropical, and Michigan is not a tropical state," Popoff said. "They're not going to be able to survive our winters, so we don't consider them invasive. We're concerned with this because it highlights the issue of pet owners releasing their pets into the wild."

Goldfish have also been released into Michigan lakes by their owners, but unlike the pacu, they survive year-round and are successfully breeding.

"We have reproducing populations of goldfish in Lake Erie and Lake St. Claire." Popoff explained. "They're an example of an aquarium disposal over time that has created a naturally reproducing population of non-native fish."

Read more at Discovery News

A.I. Learns to Replicate Human Handwriting

There was always that one kid in high school that could forge his mom's signature. Remember him? Sick and "get out of school early" notes.

Well that guy has some competition now.

Computer scientists at University College London have developed software that can analyze a piece of handwriting and then replicate it when writing new sentences, reports Future Timeline.

Oddly enough, the advance could help identify forgeries.

The program, called "My Text in Your Handwriting," uses a machine learning algorithm is built around glyphs -- which are basically the unique and specific ways that individual write certain characters. By analyzing a piece of writing, the software can learn what's consistent across the writer's style and then reproduce it.

In tests lead by Tom Haines, the scientists fed the algorithm sample texts from famous people, including Abraham Lincoln, Frida Kahlo and Arthur Conan Doyle.

Next, they wrote new sentences in the styles of these famous people and then asked people to distinguish between handwritten envelopes and ones created by the software. Watch the video below to learn more:

The computer-generated handwriting that fooled people up to 40 percent of the time.

Haines and his team think that such a system could give people who've lost the ability to write, including stroke victims, to write letters and cards to loved one.

It could also deconstruct handwritten notes to check for forgeries.

Read more at Discovery News

Purple Stubby Squid Charms Submersible Scientists

Meet the Stubby squid (Rossia pacifica), a toy-like cephalopod just spotted off the coast of California by scientists with Nautilus Live, an ongoing scientific exploration of the seafloor by the Ocean Exploration Trust.

It's found in the Northern Pacific, from Japan to Southern California and, while not new to science, it's a creature that draws a lot of attention. For obvious reasons!

They have eight small arms and two retractable tentacles. They'll burrow into the sand and wait for prey, with just their eyes sticking out. This one will dine largely on live shrimp it snares in its tentacles. Fully grown, they're about 2.36 inches long (6 centimeters) -- about 4.3 inches (11 centimeters) including arms and tentacles.

This cute fella was found about 2,950 feet (900 meters) below the surface, just minding its own business. Until, that is a remotely operated vehicle zoomed in for a closer look.

The accompanying video captures the scientists operating the vehicle as they react to the sight of this impossibly adorable seafloor critter.

From Discovery News

Aug 15, 2016

Schizophrenia emerged after humans diverged from Neanderthals

Schizophrenia vulnerability rose after the divergence of modern humans from Neanderthals, say author of a new report, suggesting that this supports the hypothesis that schizophrenia is a by-product of the complex evolution of the human brain.
Schizophrenia poses an evolutionary enigma. The disorder has existed throughout recorded human history and persists despite its severe effects on thought and behavior, and its reduced rates of producing offspring. A new study in Biological Psychiatry may help explain why-comparing genetic information of Neanderthals to modern humans, the researchers found evidence for an association between genetic risk for schizophrenia and markers of human evolution.

"This study suggests that schizophrenia is a modern development, one that emerged after humans diverged from Neanderthals," said John Krystal, Editor of Biological Psychiatry. "It suggests that early hominids did not have this disorder."

The cause of schizophrenia remains unknown, but researchers know that genetics play a significant role in the development. According to senior author Ole Andreassen from the University of Oslo in Norway and University of California, San Diego, some think that schizophrenia could be a "side effect" of advantageous gene variants related to the acquisition of human traits, like language and complex cognitive skills, that might have increased our propensity to developing psychoses.

Along with Andreassen, first authors Saurabh Srinivasan and Francesco Bettella, both from the University of Oslo, and colleagues looked to the genome of Neanderthals, the closest relative of early humans, to pinpoint specific regions of the genome that could provide insight on the origin of schizophrenia in evolutionary history.

They analyzed genetic data from recent genome-wide association studies of people with schizophrenia for overlap with Neanderthal genomic information. The analysis tells researchers the likelihood that specific regions of the genome underwent positive selection sometime after the divergence of humans and Neanderthals.

Regions of the human genome associated with schizophrenia, known as risk loci, were more likely to be found in regions that diverge from the Neanderthal genome. An additional analysis to pinpoint loci associated with evolutionary markers suggests that several gene variants that have undergone positive selection are related to cognitive processes. Other such gene loci are known to be associated with schizophrenia and have previously been considered for a causal role in the disorder.

"Our findings suggest that schizophrenia vulnerability rose after the divergence of modern humans from Neanderthals," said Andreassen, "and thus support the hypothesis that schizophrenia is a by-product of the complex evolution of the human brain."

From Science Daily

Brown dwarfs reveal exoplanets' secrets

Brown dwarfs are smaller than stars, but more massive than giant planets. As such, they provide a natural link between astronomy and planetary science. However, they also show incredible variation when it comes to size, temperature, chemistry, and more, which makes them difficult to understand, too. New work surveyed various properties of 152 suspected young brown dwarfs in order to categorize their diversity and found that atmospheric properties may be behind much of their differences.
Brown dwarfs are smaller than stars, but more massive than giant planets. As such, they provide a natural link between astronomy and planetary science. However, they also show incredible variation when it comes to size, temperature, chemistry, and more, which makes them difficult to understand, too.

New work led by Carnegie's Jacqueline Faherty surveyed various properties of 152 suspected young brown dwarfs in order to categorize their diversity and found that atmospheric properties may be behind much of their differences, a discovery that may apply to planets outside the solar system as well. The work is published by The Astrophysical Journal Supplement Series.

Scientists are very interested in brown dwarfs, which hold promise for explaining not just planetary evolution, but also stellar formation. These objects are tougher to spot than more-massive and brighter stars, but they vastly outnumber stars like our Sun. They represent the smallest and lightest objects that can form like stars do in the Galaxy so they are an important "book end" in Astronomy.

For the moment, data on brown dwarfs can be used as a stand-in for contemplating extrasolar worlds we hope to study with future instruments like the James Webb Space Telescope.

"Brown dwarfs are far easier to study than planets, because they aren't overwhelmed by the brightness of a host star," Faherty explained.

But the tremendous diversity we see in the properties of the brown dwarf population means that there is still so much about them that remains unknown or poorly understood.

Brown dwarfs are too small to sustain the hydrogen fusion process that fuels stars, so after formation they slowly cool and contract over time and their surface gravity increases. This means that their temperatures can range from nearly as hot as a star to as cool as a planet, which is thought to influence their atmospheric conditions, too. What's more, their masses also range between star-like and giant planet-like and they demonstrate great diversity in age and chemical composition.

By quantifying the observable properties of so many young brown dwarf candidates, Faherty and her team -- including Carnegie's Jonathan Gagné and Alycia Weinberger -- were able to show that these objects have vast diversity of color, spectral features, and more. Identifying the cause of this range was at the heart of Faherty's work. By locating the birth homes of many of the brown dwarfs, Faherty was able to eliminate age and chemical composition differences as the underlying reason for this great variation. This left atmospheric conditions -- meaning weather phenomena or differences in cloud composition and structure -- as the primary suspect for what drives the extreme differences between objects of similar origin.

All of the brown dwarf birthplaces identified in this work are regions also host exoplanets, so these same findings hold for giant planets orbiting nearby stars.

Read more at Science Daily

Papuan Tribe Preserves Ancient Rite of Mummification

Cradling the centuries-old remains of his mummified ancestor, tribe leader Eli Mabel lays bare an ancient tradition that has all but vanished among the Dani people in the Papuan central highlands.

The tiny, blackened, shrunken figure he carries was Agat Mamete Mabel, the chieftain that ruled over this remote village in Indonesian Papua some 250 years ago.

Honored upon death with a custom reserved only for important elders and local heroes among the Dani people -- he was embalmed and preserved with smoke and animal oil.

Nine generations on and his descendant Eli Mabel is the current chieftain in Wogi village -- an isolated hamlet outside Wamena that can be reached only by hiking and canoe.

He said the exact age of Agat Mamete Mabel was not known, but told AFP this ancestor was the last of the village to receive such a funeral. Once common among his forebears, the ritual method of smoke embalming was no longer practiced, he explained.

Christian missionaries and Muslim preachers encouraged the tribespeople to bury the corpses, and the tradition has faded as the centuries drifted by.

But Mabel is determined to retain the ancient rites and rituals for future generations.

"We must protect our culture, including the ceremonies for the mummy, the way we treat it, and maintain and fire for it," the Dani tribesman told AFP.

The mummy, decorated with pig tusks slung around the torso, a feathered headpiece, and traditional penis gourd rests in a hut known as a "honai".

This wide domed, thatch-roofed hut is tended year round by a select few villagers who keep a fire burning to ensure the corpse remains dry and preserved.

The duty of caring for the mummy often falls to Mabel, he said. He spends many nights sleeping alone in the honai, ensuring no harm befalls his ancestor.

Read more at Discovery News

Mysterious Supernovas Explode Twice, Making Powerful Magnets

A mysterious kind of supernova that appears to explode twice may be giving birth to some of the most powerful magnets in the universe, a new study finds.

Supernovas are explosions that occur when certain types of stars run out of fuel and "die." These outbursts can briefly outshine all of the millions of other stars in their galaxies.

Recently, scientists detected a very rare class of supernova, known as superluminous supernovas. These star explosions are up to 100 times brighter than other supernovas. The superluminous variety account for less than a thousandth of all supernovas, and only about 30 examples have been studied well.

They are extremely bright and can be seen for up to a year but are incredibly rare, so [they] are difficult to find and measure," said study lead author Mathew Smith, an astrophysicist at the University of Southampton in England. "We don't yet know the physical origin of these cosmic explosions that can be seen out to the beginning of the universe; that's the main focus of current and future searches."

Mysteriously, previous research suggested that some superluminous supernovas appear to explode twice. Before their main explosions, each of these supernovas experience a spike in brightness that lasts a few days.

Now, Smith and his colleagues have analyzed such a "double-peaked" superluminous supernova from almost the moment it occurred, shedding light on its origins. In their new paper, they said most superluminous supernovas may actually be double-peaked.

The researchers discovered this superluminous supernova, named DES14X3taz, in 2014 by examining data from theDark Energy Survey. DES14X3taz is located about 6.4 billion light-years from Earth.

Using the Gran Telescopio Canarias, a telescope in Spain's Canary Islands, the team of astronomers carried out follow-up observations shortly after DES14X3taz was first detected. This helped the researchers to see how the supernova's temperature evolved over time.

The researchers saw that after the initial spike of brightness, the object rapidly cooled off. Another, more powerful burst of brightness followed.

The initial spike of brightness likely coincided with the dying star's ejection of a huge bubble of material into outer space. The star's mass was about 200 times that of the sun, and the mass of the bubble of expelled material was about equivalent to the sun's, the researchers estimated. This bubble of expelled material cooled rapidly as it grew, they said.

Following the initial spike in brightness, this supernova gave birth to a magnetar, the researchers said. Magnetars are among the most powerful magnets in the universe. They are a kind of neutron star, which is the leftover core of material in a dead massive star. To reach this conclusion about the magnetar birth, the researchers compared the data with several physical models of supernovas.

The explosion created by the magnetar's formation heated up the bubble expelled by the first explosion, leading to the second, more powerful burst of brightness, the researchers found.

However, the researchers said that their most surprising discovery was "not that the supernova had a double peak, but that there's significant evidence that most superluminous supernovae do, too," Smith told

Read more at Discovery News

Aug 14, 2016

NASA's Fermi mission expands its search for dark matter

Dark matter, the mysterious substance that constitutes most of the material universe, remains as elusive as ever. Although experiments on the ground and in space have yet to find a trace of dark matter, the results are helping scientists rule out some of the many theoretical possibilities. Three studies published earlier this year, using six or more years of data from NASA's Fermi Gamma-ray Space Telescope, have broadened the mission's dark matter hunt using some novel approaches.

"We've looked for the usual suspects in the usual places and found no solid signals, so we've started searching in some creative new ways," said Julie McEnery, Fermi project scientist at NASA's Goddard Space Flight Center in Greenbelt, Maryland. "With these results, Fermi has excluded more candidates, has shown that dark matter can contribute to only a small part of the gamma-ray background beyond our galaxy, the Milky Way, and has produced strong limits for dark matter particles in the second-largest galaxy orbiting it."

Dark matter neither emits nor absorbs light, primarily interacts with the rest of the universe through gravity, yet accounts for about 80 percent of the matter in the universe. Astronomers see its effects throughout the cosmos -- in the rotation of galaxies, in the distortion of light passing through galaxy clusters, and in simulations of the early universe, which require the presence of dark matter to form galaxies at all.

The leading candidates for dark matter are different classes of hypothetical particles. Scientists think gamma rays, the highest-energy form of light, can help reveal the presence of some of types of proposed dark matter particles. Previously, Fermi has searched for tell-tale gamma-ray signals associated with dark matter in the center of our galaxy and in small dwarf galaxies orbiting our own. Although no convincing signals were found, these results eliminated candidates within a specific range of masses and interaction rates, further limiting the possible characteristics of dark matter particles.

Among the new studies, the most exotic scenario investigated was the possibility that dark matter might consist of hypothetical particles called axions or other particles with similar properties. An intriguing aspect of axion-like particles is their ability to convert into gamma rays and back again when they interact with strong magnetic fields. These conversions would leave behind characteristic traces, like gaps or steps, in the spectrum of a bright gamma-ray source.

Manuel Meyer at Stockholm University led a study to search for these effects in the gamma rays from NGC 1275, the central galaxy of the Perseus galaxy cluster, located about 240 million light-years away. High-energy emissions from NGC 1275 are thought to be associated with a supermassive black hole at its center. Like all galaxy clusters, the Perseus cluster is filled with hot gas threaded with magnetic fields, which would enable the switch between gamma rays and axion-like particles. This means some of the gamma rays coming from NGC 1275 could convert into axions -- and potentially back again -- as they make their way to us.

Meyer's team collected observations from Fermi's Large Area Telescope (LAT) and searched for predicted distortions in the gamma-ray signal. The findings, published April 20 in Physical Review Letters, exclude a small range of axion-like particles that could have comprised about 4 percent of dark matter.

"While we don't yet know what dark matter is, our results show we can probe axion-like models and provide the strongest constraints to date for certain masses," Meyer said. "Remarkably, we reached a sensitivity we thought would only be possible in a dedicated laboratory experiment, which is quite a testament to Fermi."

Another broad class of dark matter candidates are called Weakly Interacting Massive Particles (WIMPs). In some versions, colliding WIMPs either mutually annihilate or produce an intermediate, quickly decaying particle. Both scenarios result in gamma rays that can be detected by the LAT.

Regina Caputo at the University of California, Santa Cruz, sought these signals from the Small Magellanic Cloud (SMC), which is located about 200,000 light-years away and is the second-largest of the small satellite galaxies orbiting the Milky Way. Part of the SMC's appeal for a dark matter search is that it lies comparatively close to us and its gamma-ray emission from conventional sources, like star formation and pulsars, is well understood. Most importantly, astronomers have high-precision measurements of the SMC's rotation curve, which shows how its rotational speed changes with distance from its center and indicates how much dark matter is present. In a paper published in Physical Review D on March 22, Caputo and her colleagues modeled the dark matter content of the SMC, showing it possessed enough to produce detectable signals for two WIMP types.

"The LAT definitely sees gamma rays from the SMC, but we can explain them all through conventional sources," Caputo said. "No signal from dark matter annihilation was found to be statistically significant."

In the third study, researchers led by Marco Ajello at Clemson University in South Carolina and Mattia Di Mauro at SLAC National Accelerator Laboratory in California took the search in a different direction. Instead of looking at specific astronomical targets, the team used more than 6.5 years of LAT data to analyze the background glow of gamma rays seen all over the sky.

The nature of this light, called the extragalactic gamma-ray background (EGB) has been debated since it was first measured by NASA's Small Astronomy Satellite 2 in the early 1970s. Fermi has shown that much of this light arises from unresolved gamma-ray sources, particularly galaxies called blazars, which are powered by material falling toward gigantic black holes. Blazars constitute more than half of the total gamma-ray sources seen by Fermi, and they make up an even greater share in a new LAT catalog of the highest-energy gamma rays.

Some models predict that EGB gamma rays could arise from distant interactions of dark matter particles, such as the annihilation or decay of WIMPs. In a detailed analysis of high-energy EGB gamma rays, published April 14 in Physical Review Letters, Ajello and his team show that blazars and other discrete sources can account for nearly all of this emission.

"There is very little room left for signals from exotic sources in the extragalactic gamma-ray background, which in turn means that any contribution from these sources must be quite small," Ajello said. "This information may help us place limits on how often WIMP particles collide or decay."

Read more at Science Daily

Seeing the invisible: Visible light superlens made from nanobeads

Conceptual drawing of nanoparticle-based metamaterial solid immersion lens (mSIL) (b) Lab made mSIL using titanium dioxide nanoparticles (c) SEM image of 60 nm sized imaging sample (d) corresponding superlens imaging of the 60 nm samples by the developed mSIL.
Nanobeads are all around us- and are, some might argue, used too frequently in everything from sun-screen to white paint, but a new ground-breaking application is revealing hidden worlds.

A paper in Science Advances provides proof of a new concept, using new solid 3D superlenses to break through the scale of things previously visible through a microscope.

Illustrating the strength of the new superlens, the scientists describe seeing for the first time, the actual information on the surface of a Blue Ray DVD. That shiny surface is not as smooth as we think. Current microscopes cannot see the grooves containing the data- but now even the data itself is revealed.

Led by Dr Zengbo Wang at Bangor University, UK and Prof Limin Wu at Fudan University, China, the team created minute droplet-like lens structures on the surface to be examined. These act as an additional lens to magnify the surface features previously invisible to a normal lens.

Made of millions of nanobeads, the spheres break up the light beam. Each bead refracts the light, acting as individual torch-like minute beam. It is the very small size of each beam of light which illuminate the surface, extending the resolving ability of the microscope to record-breaking levels. The new superlens adds 5x magnification on top of existing microscopes.

Extending the limit of the classical microscope's resolution has been the 'El Dorado' or 'Holy Grail' of microscopy for over a century. Physical laws of light make it impossible to view objects smaller than 200 nm -- the smallest size of bacteria, using a normal microscope alone. However, superlenses have been the new goal since the turn of the millennium, with various labs and teams researching different models and materials.

"We've used high-index titanium dioxide (TiO2) nanoparticles as the building element of the lens. These nanoparticles are able to bend light to a higher degree than water. To explain, when putting a spoon into a cup of this material, if it were possible, you'd see a larger bend where you spoon enters the material than you would looking at the same spoon in a glass of water," Dr Wang says.

"Each sphere bends the light to a high magnitude and splits the light beam, creating millions of individual beams of light. It is these tiny light beams which enable us to view previously unseen detail."

Wang believes that the results will be easily replicable and that other labs will soon be adopting the technology and using it for themselves.

The advantages of the technology is that the material, titanium dioxide, is cheap and readily available, and rather than buying a new microscope, the lenses are applied to the material to be viewed, rather than to the microscope.

Read more at Science Daily