Strange silk: Why rappelling spiders don't spin out of control

The golden silk orb weaver (Nephila pilipes) creates dragline silk that prevents it from spinning while hanging from its web.

The last time you watched a spider drop from the ceiling on a line of silk, it likely descended gracefully on its dragline instead of spiraling uncontrollably, because spider silk has an unusual ability to resist twisting forces.

In a new paper appearing this week in Applied Physics Letters, from AIP Publishing, researchers from China and the U.K. showed that unlike human hair, metal wires or synthetic fibers, spider silk partially yields when twisted. This property quickly dissipates the energy that would otherwise send an excited spider spinning on the end of its silk.

"Spider silk is very different from other, more conventional materials," said Dabiao Liu of Huazhong University of Science and Technology. "We find that the dragline from the web hardly twists, so we want to know why."

A greater understanding of how spider silk resists spinning could lead to biomimetic fibers that mimic these properties for multiple potential uses such as in violin strings, helicopter rescue ladders and parachute cords. "If we understood how spider silk achieves this, then maybe we could incorporate the properties into our own synthetic ropes," said David Dunstan of Queen Mary University of London.

Spiders use dragline silk for the outer rim and spokes of their webs, and as a lifeline when dropping to the ground. The material has intrigued scientists because of its incredible strength, stretchiness and ability to conduct heat, but little research has focused on its torsional properties -- how it responds to twisting.

Researchers used a torsion pendulum, the same tool used by Henry Cavendish to weigh the Earth in the 1790s, to investigate dragline silk from two species of golden silk orb weavers. They collected strands of silk from captive spiders and suspended the strands inside a cylinder using two washers at the end to mimic a spider. The cylinder isolated the silk from environmental disturbances and kept the strand at a constant humidity, because water can cause the fibers to contract. A rotating turntable twisted the silk while a high-speed camera recorded the silk's back and forth oscillations over hundreds of cycles.

Unlike synthetic fibers and metals, spider silk deforms slightly when twisted, which releases more than 75 percent of its potential energy, and the oscillations rapidly slow. After twisting, the silk partially snaps back.

The team suspects that this unusual behavior is linked to the silk's complex physical structure, consisting of a core of multiple fibrils inside a skin. Each fibril has segments of amino acids in organized sheets and others in unstructured looping chains. They propose that torsion causes the sheets to stretch like elastic, and warp the hydrogen bonds linking the chains, which deform like plastic. The sheets can recover their original shape, but the chains remain partially deformed. The pendulum exhibits this change with reduced magnitude of the silk's oscillations, as well as a shifting of the equilibrium point of the oscillation.

Read more at Science Daily

Earth's magnetic field 'simpler than we thought'

The geomagnetic field is critical to life on Earth. Without it, charged particles from the sun (the "solar wind") would blow away the atmosphere, scientists say.

Scientists have identified patterns in Earth's magnetic field that evolve on the order of 1,000 years, providing new insight into how the field works and adding a measure of predictability to changes in the field not previously known.

The discovery also will allow researchers to study the planet's past with finer resolution by using this geomagnetic "fingerprint" to compare sediment cores taken from the Atlantic and Pacific oceans.

Results of the research, which was supported by the National Science Foundation, were recently published in Earth and Planetary Science Letters.

The geomagnetic field is critical to life on Earth. Without it, charged particles from the sun (the "solar wind") would blow away the atmosphere, scientists say. The field also aids in human navigation and animal migrations in ways scientists are only beginning to understand. Centuries of human observation, as well as the geologic record, show our field changes dramatically in its strength and structure over time.

Yet in spite of its importance, many questions remain unanswered about why and how these changes occur. The simplest form of magnetic field comes from a dipole: a pair of equally and oppositely charged poles, like a bar magnet.

"We've known for some time that Earth is not a perfect dipole, and we can see these imperfections in the historical record," said Maureen "Mo" Walczak, a post-doctoral researcher at Oregon State University and lead author on the study. "We are finding that non-dipolar structures are not evanescent, unpredictable things. They are very long-lived, recurring over 10,000 years -- persistent in their location throughout the Holocene.

"This is something of a Holy Grail discovery," she added, "though it is not perfect. It is an important first step in better understanding the magnetic field, and synchronizing sediment core data at a finer scale."

Some 800,000 years ago, a magnetic compass' needle would have pointed south because Earth's magnetic field was reversed. These reversals typically happen every several hundred thousand years.

While scientists are well aware of the pattern of reversals in Earth's magnetic field, a secondary pattern of geomagnetic "wobble" within periods of stable polarity, known as paleomagnetic secular variation, or PSV, may be a key to understanding why some geomagnetic changes occur.

Earth's magnetic field does not align perfectly with the axis of rotation, which is why "true north" differs from "magnetic north," the researchers say. In the Northern Hemisphere this disparity in the modern field is apparently driven by regions of high geomagnetic intensity that are centered beneath North America and Asia.

"What we have not known is whether this snapshot has any longer-term meaning -- and what we have found out is that it does," said Joseph Stoner, an Oregon State University paleomagnetic specialist and co-author on the study.

When the magnetic field is stronger beneath North America, or in the "North American Mode," it drives steep inclinations and high intensities in the North Pacific, and low intensities in Europe with westward declinations in the North Atlantic. This is more consistent with the historical record.

The alternate "European mode" is in some ways the opposite, with shallow inclination and low intensity in North Pacific, and eastward declinations in the North Atlantic and high intensities in Europe.

"As it turns out, the magnetic field is somewhat less complicated than we thought," Stoner said. "It is a fairly simple oscillation that appears to result from geomagnetic intensity variations at just a few recurrent locations with large spatial impacts. We're not yet sure what drives this variation, though it is likely a combination of factors including convection of the outer core that may be biased in configuration by the lowermost mantle."

The researchers were able to identify the pattern by studying two high-resolution sediment cores from the Gulf of Alaska that allowed them to develop a 17,400-year reconstruction of the PSV in that region. They then compared those records with sediment cores from other sites in the Pacific Ocean to capture a magnetic fingerprint, which is based on the orientation of the magnetite in the sediment, which acts as a magnetic recorder of the past.

The common magnetic signal found in the cores now covers an area spanning from Alaska to Oregon, and over to Hawaii.

"Magnetic alignment of distant environmental reconstructions using reversals in the paleomagnetic record provides insights into the past on a scale of hundreds of thousands of years," Walczak said. "Development of the coherent PSV stratigraphy will let us look at the record on a scale possibly as short as a few centuries, compare events between ocean basins, and really get down to the nitty-gritty of how climate anomalies are propagated around the planet on a scale relevant to human society."

Read more at Science Daily

Sticking your neck out: How did plesiosaurs swim with such long necks?

This is a side view of the plesiosaur model in the hydrodynamic simulation.

When dinosaurs ruled the land, plesiosaurs ruled the oceans. Famous for their incredibly long necks -- some of which were up to 7 metres long -- plesiosaurs have remained an evolutionary mystery for hundreds of years. Pernille V. Troelsen, a PhD student at Liverpool John Moores University, UK is simulating plesiosaur locomotion with a 3D model to understand how they could swim with such long necks.

"A steady neck would be more hydrodynamic than a bent neck, and due to the pressure on a bent neck, plesiosaurs would probably only bend them when moving at slow speeds or when floating,' says Ms Troelsen.

She reveals that not only increasing the bend in a plesiosaurs neck would have a big effect on the production of 'hydrodynamic drag', but the location of the bending may also play a large role. She adds that plesiosaurs would likely have had a more patient hunting style similar to today's crocodiles and snakes.

"We have some ideas about why they had long necks and they mainly concern feeding strategies, but we still don't fully understand how they moved," explains Ms Troelsen. "These were extremely successful animals that existed for 140 million years, but we don't have any living equivalents to compare with."

Several possible theories suggest that plesiosaurs may have developed long necks to extend their feeding range. By laying immobile on the sea floor or floating at the surface and using their protruding necks to hunt, they may have been able to sneak up on their prey more easily, or simply been more effective at snapping up fast-moving prey.

To test the hydrodynamic effects of different neck bending degrees and locations, Ms Troelsen created a digital 3D model based on a simplified plesiosaur body shape and uses computational fluid dynamics to visualise and determine how bending the neck affects the flow of water around the animal.

To improve these 3D models for in future, Ms Troelsen will be looking at fossil evidence for more information about the shape and bendiness of plesiosaur necks: "Further studies will include digitized neck vertebrae from actual plesiosaurs which will allow us to have an even more realistic approach."

Read more at Science Daily

Hubble pushed beyond limits to spot clumps of new stars in distant galaxy

In this Hubble photograph of a distant galaxy cluster, a spotty blue arc stands out against a background of red galaxies. That arc is actually three separate images of the same background galaxy. The background galaxy has been gravitationally lensed, its light magnified and distorted by the intervening galaxy cluster. On the right: How the galaxy would look to Hubble without distortions.

When it comes to the distant universe, even the keen vision of NASA's Hubble Space Telescope can only go so far. Teasing out finer details requires clever thinking and a little help from a cosmic alignment with a gravitational lens.

By applying a new computational analysis to a galaxy magnified by a gravitational lens, astronomers have obtained images 10 times sharper than what Hubble could achieve on its own. The results show an edge-on disk galaxy studded with brilliant patches of newly formed stars.

"When we saw the reconstructed image we said, 'Wow, it looks like fireworks are going off everywhere,'" said astronomer Jane Rigby of NASA's Goddard Space Flight Center in Greenbelt, Maryland.

The galaxy in question is so far away that we see it as it appeared 11 billion years ago, only 2.7 billion years after the big bang. It is one of more than 70 strongly lensed galaxies studied by the Hubble Space Telescope, following up targets selected by the Sloan Giant Arcs Survey, which discovered hundreds of strongly lensed galaxies by searching Sloan Digital Sky Survey imaging data covering one-fourth of the sky.

The gravity of a giant cluster of galaxies between the target galaxy and Earth distorts the more distant galaxy's light, stretching it into an arc and also magnifying it almost 30 times. The team had to develop special computer code to remove the distortions caused by the gravitational lens, and reveal the disk galaxy as it would normally appear.

The resulting reconstructed image revealed two dozen clumps of newborn stars, each spanning about 200 to 300 light-years. This contradicted theories suggesting that star-forming regions in the distant, early universe were much larger, 3,000 light-years or more in size.

"There are star-forming knots as far down in size as we can see," said doctoral student Traci Johnson of the University of Michigan, lead author of two of the three papers describing the research.

Without the magnification boost of the gravitational lens, Johnson added, the disk galaxy would appear perfectly smooth and unremarkable to Hubble. This would give astronomers a very different picture of where stars are forming.

While Hubble highlighted new stars within the lensed galaxy, NASA's James Webb Space Telescope will uncover older, redder stars that formed even earlier in the galaxy's history. It will also peer through any obscuring dust within the galaxy.

Read more at Science Daily

Milky Way could have 100 billion brown dwarfs

Artist's impression of a T-type brown dwarf.

Our galaxy could have 100 billion brown dwarfs or more, according to work by an international team of astronomers, led by Koraljka Muzic from the University of Lisbon and Aleks Scholz from the University of St Andrews. On Thursday 6 July Scholz will present their survey of dense star clusters, where brown dwarfs are abundant, at the National Astronomy Meeting at the University of Hull.

Brown dwarfs are objects intermediate in mass between stars and planets, with masses too low to sustain stable hydrogen fusion in their core, the hallmark of stars like the Sun. After the initial discovery of brown dwarfs in 1995, scientists quickly realised that they are a natural by-product of processes that primarily lead to the formation of stars and planets.

All of the thousands of brown dwarfs found so far are relatively close to the Sun, the overwhelming majority within 1500 light years, simply because these objects are faint and therefore difficult to observe. Most of those detected are located in nearby star forming regions, which are all fairly small and have a low density of stars.

In 2006 the team began a new search for brown dwarfs, observing five nearby star forming regions. The Substellar Objects in Nearby Young Clusters (SONYC) survey included the star cluster NGC 1333, 1000 light years away in the constellation of Perseus. That object had about half as many brown dwarfs as stars, a higher proportion than seen before.

To establish whether NGC 1333 was unusual, in 2016 the team turned to another more distant star cluster, RCW 38, in the constellation of Vela. This has a high density of more massive stars, and very different conditions to other clusters.

RCW 38 is 5500 light years away, meaning that the brown dwarfs are both faint, and hard to pick out next to the brighter stars. To get a clear image, Scholz, Muzic and their collaborators used the NACO adaptive optics camera on the European Southern Observatory's Very Large Telescope, observing the cluster for a total of 3 hours, and combining this with earlier work.

The researchers found just as many brown dwarfs in RCW 38 -- about half as many as there are stars -- and realised that the environment where the stars form, whether stars are more or less massive, tightly packed or less crowded, has only a small effect on how brown dwarfs form.

Scholz says: "We've found a lot of brown dwarfs in these clusters. And whatever the cluster type, the brown dwarfs are really common. Brown dwarfs form alongside stars in clusters, so our work suggests there are a huge number of brown dwarfs out there."

Read more at Science Daily

Scientists Analyze Possible Vegetation on the TRAPPIST-1 Exoplanets

The discovery of the TRAPPIST-1 planetary system earlier this year generated quite a buzz among planet hunters and astrobiologists alike. The system contains seven worlds thought to be Earth-sized and rocky, with three of the planets orbiting in the star’s habitable zone. Although not much is yet known about the conditions on these worlds, the prospect of finding life on at least one of these planets is intriguing — and one group of scientists are now saying that the discovery could open up new perspectives into the investigation of planetary climates of Earth-sized exoplanets.

Researchers from Europe have developed a new model in order to study whether liquid water could be maintained on planetary surfaces in various conditions. Their model considers the effect of land/ocean distribution and even the fraction of vegetation that could cover a planet’s surface. In their findings, one planet — TRAPPIST-1d — stood out as being potentially the most habitable planet in that system.

 “We can investigate the main features of each planet by using a simple model, particularly useful when little information is known about planetary characteristics, since for more complex models we need to know several planetary features,” said Tommaso Alberti, a physicist at the University of Calabria in Italy, in an email to Seeker. 

Alberti and his colleagues say in their paper that their model is a simple climate-vegetation energy-balance model. They used it to study the seven TRAPPIST-1 planets to determine their climate dependence on three things: the global albedo (i.e. the energy from the star that is reflected back to space from the planet), the fraction of vegetation that could cover their surfaces, and the different greenhouse conditions.

“The model allows us to investigate whether liquid water could be maintained on the planetary surfaces (i.e., by defining a ‘surface water zone’) in different planetary conditions, with or without the presence of greenhouse effect,” the team wrote in their paper.

Determining the potential habitability of a specific exoplanet is more complicated than just figuring out if the planet is in the host star’s habitable zone. Numerous other characteristics factor into it, as the planets in our own solar system attest. While Venus, Earth, and Mars are all considered to be in the Sun’s habitable zone, Earth is currently the only habitable planet — by human standards, anyway. The runaway greenhouse atmosphere on Venus is too thick to support life as we know it, while Mars’ thin atmosphere doesn’t allow liquid water to stay on the planet’s surface.

On Earth, we know that everywhere there is water, there is life. But even though the TRAPPIST-1 planets are Earth-size, with some planets in the habitable zone, the conditions in that planetary system are very different from ours. The seven planets orbit quite close to their ultra-cool red dwarf star, with orbits lasting between 1.5 and 20 days, compared to Earth's 365 days. Because they are so close to their star, the planets are likely tidally locked, with one side always facing the star. This means conditions could vary widely from one side of the planet to the other. Additionally, the star gives off different wavelengths of light than our Sun. TRAPPIST-1 is much redder, and emits longer wavelengths, including those in the near-infrared.

So, how do you try to answer a complicated question like potential habitability with so many variables? Alberti and his colleagues responded by making their model as simple as possible.

The research team said that one of the drawbacks of using detailed climate models is the necessarily large pool of assumptions of atmospheric and surface conditions. So instead, they used a simple zero-dimensional energy-balance model “which allows the extraction of global information on the climate evolution by using the actual knowledge about the planetary system.”

Zero-dimensional energy balance models have been used to study Earth’s climate. Such a model takes a single planet’s characteristics separately instead of using a broader model for the entire solar system. More specifically, the model uses the planet as a single point, using an average global temperature.

“The term zero-dimensional is related to the fact that we do not take into account latitudinal and longitudinal variations into the energy balance,” Alberti told Seeker, “between incoming stellar radiation, which depends on the star-planet distance, and the outcoming planetary radiation, depending on the vegetation (and so on the albedo) and on the atmospheric composition (and so on the greenhouse effect).”

 This model has the advantage of transparency through minimal assumptions, allowing comparative sets of models to be studied. The researchers looked at several situations, from completely barren, rocky planets to Earth-like conditions, both neglecting and considering the greenhouse effect, to explore different possible climates and make a comparative study of TRAPPIST-1 planetary system climates.

“We are able to investigate different scenarios for TRAPPIST planetary system moving from rocky planets to Earth-like planets with similar and/or different greenhouse conditions and to underline the role of vegetation in defining a particular climate state,” Alberti said. “Finally, by defining the surface water zone, defined as the circumstellar region where a planet can host liquid water on its surface, we showed that this zone is strongly dependent on the different parameters of the model and, in particular, on the initial fraction of vegetation coverage, the presence of oceans and the greenhouse effect.”

Alberti said it is well known that vegetation is able to change planetary albedo (i.e., the fraction of incidental radiation reflected back to space), and consequently it affects temperature evolution. Previous studies have shown that if vegetation is widespread enough, it would affect the reflective properties of the whole planet. The albedo on a vegetated planet is much less than on a non-vegetated planet.

Alberti and his team previously investigated an energy-balance model with two types of vegetation using the famous Daisyworld model, which is a 1983 computer simulation that creates a hypothetical world covered with either white daisies or black daisies to study elements in the Earth-Sun system.

“In that study, we found that vegetation is one of the main feedbacks which affect temperature evolution, together with the greenhouse effect,” Alberti said. Additionally, an ocean vs. land also has a big effect, as oceans have a very low albedo.

“By defining the surface water zone, defined as the circumstellar region where a planet can host liquid water on its surface,” Alberti explained, “we showed that this zone is strongly dependent on the different parameters of the model and, in particular, on the initial fraction of vegetation coverage, the presence of oceans and the greenhouse effect.”

The team said they determined that outer planets (f, g, and h) are too cold and cannot host liquid water on their surfaces. But they found that the three “inner” planets — TRAPPIST1-b, c, and d — appear to have the ability to hold water on their surfaces.

However, the fourth planet, TRAPPIST-1d, was found to be the most stable from an Earth-like perspective, “since it resides in the surface water zone for a wide range of reasonable values of the model parameters.” This result differs from a paper that came out earlier this year that used a more detailed three-dimensional model, which took into account a variety of greenhouse gases and showed that the best candidate for a habitable ocean-covered planet was TRAPPIST1-e. Alberti’s team said their model showed water oceans could only exist on the “e” planet with greenhouse effect conditions different from the Earth.

But in their paper, Alberti and his colleagues did allow that the greenhouse effect needs to be properly considered, since it is one of the main feedbacks in regulating thermal energy balance. They are looking to continue their research using an improved version of their model.

Read more at Discovery News

Stephen Hawking Says Earth Could Become a Hothouse Planet Like Venus

Hot Earth

Earth could turn into a hothouse planet like Venus, with boiling oceans and acid rain, if humans don't curb irreversible climate change, physicist Stephen Hawking claimed in a recent interview.

"We are close to the tipping point, where global warming becomes irreversible. Trump's action could push the Earth over the brink, to become like Venus, with a temperature of 250 degrees [Celsius], and raining sulfuric acid," he told BBC News, referring to the president's decision to pull the US out of the Paris climate deal.

But most climate experts say that scenario is a dramatic and implausible exaggeration: Relative to Venus, planet Earth is much farther from the sun and given its chemical makeup will never have such a thick carbon dioxide atmosphere, so it could not likely reach temperatures of 482°Fahrenheit (250°C) that Hawking described in the interview, they say.

However, the general trend of runaway and catastrophic climate change is a real concern, experts said.

"Hawking is taking some rhetorical license here," Michael Mann, a climate scientist at the Pennsylvania State University, told Live Science in an email. "Earth is further away from the sun than Venus and likely cannot experience a runaway greenhouse effect in the same sense as Venus — i.e. a literal boiling away of the oceans. However Hawking's larger point — that we could render the planet largely uninhabitable for human civilization if we do not act to avert dangerous climate change — is certainly valid."

Hothouse planet

Venus is the second planet from the sun and the brightest planet in the solar system; though the planet is named after the Roman goddess of love and desire, don't expect to take a trip to the balmy planet with your sweetheart anytime soon. Despite being the same size as Earth and having roughly the same gravity as our home planet, it's a far cry from our water-drenched planet. Venus is the hottest planet in the solar system, with temperatures reaching 870°F (466°C). The reason for these sweltering temperatures is Venus' thick carbon-dioxide atmosphere that is dotted with sulfuric acid clouds; the atmosphere traps much more heat than our own does. It is also much closer to the sun, meaning it absorbs much more solar radiation than Earth. Churning volcanoes add to Venus' reputation as an inferno.

The leading theory about how Venus came to be such a hellscape is that the planet got caught in a feedback loop, wherein the planet absorbed more solar radiation than it released, causing more water vapor to get trapped in its atmosphere. That, in turn, led to greater heat absorption, and runaway warming (also called a runaway greenhouse effect).

"Basically, Venus was in a state of heat stroke — the planet was in a warming state and it couldn't cool down," said Tyler Robinson, an astrobiologist at the University of Washington.

Unlikely on Earth

Though most humans take for granted the relative constancy of an Earth-like climate, our planet has undergone dramatic changes in its 4.5-billion-year history. During the Great Oxygenation Event, around 2.5 billion years ago, photosynthetic cyanobacteria fueled a huge rise in oxygen in the atmosphere.

Around 650 million years ago, the entire planet froze, in a phenomenon known as "snowball Earth." And during the dinosaur age, the planet was, on average 18°F (10°C) hotter than it is now, with a carbon dioxide-rich atmosphere. And huge "carbon excursions" have led to massive extinctions in the past — such as the end-Permian extinction around 252 million years ago, when roughly 95 percent of sea life died out due to ocean acidification.

So it's not unreasonable to contemplate the possibility of a runaway climate scenario, Robinson said. Still, most experts, including Robinson, see that possibility as incredibly unlikely.

While in theory, a process similar to the one experienced on Venus could take place on Earth, the process would most likely occur over hundreds of millions of years, most experts believe, Robinson said. There are also very low odds that Earth's oceans could literally boil away like Venus' primeval oceans did, Robinson said.

Earth, meanwhile, is protected from solar radiation by an atmosphere that is dramatically different from that of Venus.

"Venus' atmosphere is about 100 times thicker than Earth's atmosphere, and composed almost entirely of CO2 [carbon dioxide]," Robinson said. By contrast, Earth's atmosphere is mostly molecular nitrogen and oxygen, with less than 0.04 percent coming from carbon dioxide, Robinson told Live Science in an email.

Without a thick carbon dioxide atmosphere and the extra dose of solar radiation from the sun, only willful malice is likely to cause a runaway greenhouse scenario, said Kevin Zahnle, a space scientist at NASA Ames Research Center, who has analyzed runaway greenhouse projections for the planet.

"There is no rational expectation of a runaway [greenhouse effect] in the facts as we know them," Zahnle told Live Science in an email.

For one, there were much warmer climates on Earth in the relatively recent past, such as during the Eocene epoch (between 56 million and 34 million years ago), and no signs of a runaway greenhouse effect, Zahnle said. At that time, CO2 levels were likely three times higher than they are now. Even imagining a future with cars, planes, and air conditioning on full blast, no climate projections predict such high levels of CO2 in our atmosphere, he said.

"A runaway greenhouse effect is not in the cards," added Kevin Trenberth, a climate scientist at the National Center for Atmospheric Research in Boulder, Colorado.

Of course, there is always the possibility of deliberate sabotage, Zahnle said.

"Dr. Evil might consider an engineering solution akin to the engineering solutions proposed to terraform Mars, but the scale of the effort would be stupendous," Zahnle said. "You'd need fluorocarbons — so Dr. Evil would need to create a worldwide religion dedicated to the sacred use of hairspray and underarm deodorants," Zahnle said. (In the past, some consumer aerosol products contained fluorocarbons, though the US banned the ingredients in the late 1970s.)

Climate catastrophe possible

Nontheless, Earth doesn't have to become like Venus for life on Earth to become hellish.

The Paris Agreement aimed to keep warming below 3.6°F (2°C) compared with preindustrial temperatures, but even reaching that level for sustained periods could cause changes that are already underway to completely disrupt ecosystems and farming, Trenberth told Live Science.

Read more at Discovery News

Archaeologists put sound back into a previously silent past

Fajada Butte in Chaco Canyon at the Chaco Culture National Historical Park in New Mexico.

Many attempts to explain how past people experienced their wider world have focused on sight at the expense of sound, but researchers from the University at Albany and the University at Buffalo have developed a tool that puts sound back into the ancient landscape.

UAlbany's Kristy Primeau and UB's David Witt use GIS technology to advance a largely theoretical discussion into a modeled sensory experience to explore how people may have heard their surroundings throughout an entire archaeological landscape, or soundscape.

The results, published in the Journal of Archaeological Science: Reports, have more fully animated the ancient world and opened a discussion about how people at various locations, at sites ranging from sacred to political, experienced their soundscapes. The findings ultimately color what was formerly a sterile space into a living place -- and sound ties itself to the identity of that place.

This attempt to infuse character into the material world and incorporate the relationship between people and their surroundings is part of what's called phenomenology.

"From a phenomenological perspective, the difference between a space and a place is critical. People don't live in a vacuum and we have to look at all aspects of the lived experience," says Primeau, an archeologist and PhD candidate at UAlbany. "There is more to the experience of the landscape than just being present there."

"The phenomenological approach tries to learn about the past by finding those things that resonate with the way we experience the landscape now," says Primeau. When people share a common culture it contributes to a general conception of experience within the landscape that includes meaning, memory and identity. "Sound is one way in which we hope to understand a multifaceted experience of the people that lived in these 'places.'"

Primeau and Witt are both employees of the New York State Department of Environmental Conservation (DEC). Sound, and its effect on people and animals, is among the factors the DEC considers as part of its permitting process.

Witt, who is a UB research associate in the Department of Anthropology, developed a spreadsheet for the DEC that calculates the impact of sound on the environment. The spreadsheet models the effect of distance and intervening features on sound. That data provides a two-dimensional, point-to-point analysis that the researchers expanded further into a program for GIS technology that models sound over the entire landscape, from one point to all surrounding locations.

With this three-dimensional tool, Primeau and Witt explored Chaco Canyon, New Mexico, a major cultural center for ancestral Pueblo people, which reached its high point around A.D. 1040.

Chaco Canyon offered advantages and curiosities that made it an attractive location to study. The required data for the site was readily available, but it also illustrates the sight-centered focus of archaeological research.

"Southwestern archaeologists have been talking about whether or not buildings and other structures were placed in their locations so they could see people, or be seen by people," says Witt. "It got me wondering if these sites were located where they were to hear, as well as see, other locations."

They explored the possible relationships between the features of the built environment and the canyon's performance space. Their work suggests that certain features could have been placed at their locations so culturally relevant sounds like a raised voice, which might serve as an alert, could be heard elsewhere.

But it's the sound of musical instruments that might provide the most direct evidence of intentional design, specifically the conch shell trumpet.

"Individuals at [four different points] would have heard a conch shell trumpet blown on the platform found at Pueblo Bonito," Primeau and Witt write in their paper. "We interpret this to illustrate that events at the mound were not just meant to be experienced in front of Pueblo Bonito, but throughout Downtown Chaco."

Read more at Science Daily

Ancient animal thought to be first air breather on land loses claim to fame

These are examples of zircon grains used in a University of Texas at Austin study that showed the animal thought to be the oldest land-based air breather is younger than thought. Grain numbers and ages are indicated by the numbers.

Some good scientific sleuthing by an undergraduate at The University of Texas at Austin has helped rewrite one of the earliest chapters in the planet's evolutionary history. The research, led by the UT Jackson School of Geosciences, has shown that the millipede thought to be the world's oldest known air-breathing land creature is in fact about 14 million years younger than previously thought and cannot be the original land breather.

The paper was published June 28 in the journal PLOS ONE. The study focuses on a species of millipede called Pneumodesmus newmani, which was thought to have been breathing air on solid ground during the late Silurian period some 428 million years ago. All other animal fossils discovered before this time have been from animals that lived and breathed under water.

The millipede fossil was discovered by an amateur paleontologist in 2004 in Aberdeenshire, Scotland, and dated by testing plant spores in sediment found in the general area, a method that contains a significant amount of scientific uncertainty compared with radiometric dating methods, said Elizabeth Catlos, a study author and associate professor in the Jackson School's Department of Geological Sciences.

"The 428 million year age wasn't obtained using radiometric techniques because no one could get the radioactive minerals out of these soils," she said.

Catlos, who obtained the soil samples from co-author Michael Brookfield of the University of Massachusetts Boston, tasked Jackson School senior Stephanie Suarez, the paper's lead author, with finding grain-sized zircons in the sediment that could be dated in the Jackson School's Laser Ablation Inductively Coupled Plasma Mass Spectrometry Laboratory. Zircons are minerals that trap radioactive elements inside of them when they form, which can help scientists more accurately determine the age of rock or sediment where they're found.

The zircon samples were from ancient volcanic ash beds directly above and below where the millipede specimen was found. Brookfield, who is from Scotland, said he has been collecting samples from the area since he was a teenager and has long been interested in more precisely dating the sediment where the well-known specimen was discovered.

This job was particularly challenging because the clay sediment Brookfield sent to the Jackson School was loose in plastic bags and unlike the solid rock that Catlos is used to studying. Suarez, who was introduced to the geosciences in high school as part to the Jackson School's GeoFORCE outreach program, initially tried the standard method of heavy mineral separation, which involves crushing the rock and using bromoform (an organic solvent) to separate out heavier minerals.

"When I attempted it, the ashes clumped together, and no zircons sank to the bottom," she said. "It was very messy and unsuccessful."

Undeterred, Suarez combed scientific literature looking for ideas and came across a 2014 study led by Gregory Hoke of Syracuse University that pioneered a method of isolating nonclay components from clay-rich material by constructing and using an ultrasonic clay separator.

"I had to get creative," Suarez said. "We have a very small sonicator in our lab that we use to clean thin sections. I used that, a Tupperware container and some hydrogen peroxide. It worked. I was very excited."

Ultimately, Suarez was able to collect 74 zircons to be analyzed and dated. More than 10 of the zircons were younger than 428 million years ago, with the youngest being about 414 million years old. This places the specimen in a completely different geologic era, the Devonian, a classification that bursts the millipede's uniqueness. Many fossils of land-breathing organisms, mainly insects and arthropods, have been recovered from this era.

Read more at Science Daily

Scientists Discover ‘Doubly-Charmed’ Subatomic Particle

Large Hadron Collider, Geneva, Switzerland

European scientists said Thursday they have discovered a new subatomic particle containing a never-before-seen combination of quarks — the most basic building blocks of matter.

The particle, a baryon dubbed Xicc++, contains two heavy "charm" quarks and one "up" quark, and has about four times the mass of a more familiar baryon — the proton.

The particle is predicted in the Standard Model of particle physics, and its discovery was "not a shock," said Matthew Charles of the LPNHE physics lab in Paris.

He is one of about 800 scientists to attach their names to the discovery by the Large Hadron Collider (LHC) of the European Organization for Nuclear Research (CERN).

The collider is most famous for discovering the Higgs boson, which confers mass on matter.

The new particle is the first seen with two such heavy quarks, said the team.

There are six types of quark, with exotic names such as "charm," "strange," and "beauty."

The "charm," "top," and "bottom" quarks are the heaviest types.

Quarks make up baryons such as protons and neutrons that comprise most of the mass in the known universe.

Baryons gather together in atoms, which form the molecules that constitute matter.

"This type of particle, these doubly-charmed baryons... they've been quite elusive," Charles told AFP.

From their short-lived existence in the early Universe, none are left today. And to produce them in the lab requires an extreme concentration of energy, such as can be generated by the new, upgraded LHC.

The Xicc++ is an unstable baryon, said Charles. It lives for "a very small fraction of a second" before decaying into other, lighter particles.

Its discovery will allow scientists to continue testing the Standard Model of physics — the mainstream theory of the fundamental particles that make up matter, and the forces that govern them.

It does not, however, explain dark matter, or why there is more matter than anti-matter in the universe.

Critically, the model is incompatible with Einstein's theory of general relativity — the force of gravity as we know it does not seem to work at the subatomic quantum scale.

"A big part of our work as a field is trying to put our finger on the place where the Standard Model breaks down," to eventually find alternative explanations, said Charles.

Read more at Seeker

Sexual Violence Among Baboons Shows Links to Human Behavior

A male baboon attacking a female

Their relationship began innocently enough. He started to pay extra attention to her, and her attraction to him grew over time. One day, however, the dynamic changed. While she was peacefully sitting having a meal, he attacked her without warning. The unprovoked abuse continued, yet she stayed with him, still feeling the attraction and too afraid to go anywhere else. Later, his presence benefitted their youngsters.

Such is a typical story of a wild, female chacma baboon, which in many ways is a tale that mirrors those of certain chimpanzees and human domestic abuse survivors the world over, a new study published in the journal Current Biology indicates. Males of all three species may use long-term sexual intimidation to control their mates, suggesting that this mating strategy has a long history in primates, including humans.  

The behavior has often been reported in our species, and has been documented in male chimps over the past decade. The new study focuses on chacma baboons, which are among the largest of all monkeys.

“What is interesting is that the forms of sexual violence reported in chacma baboons may resemble some common patterns of sexual intimidation in humans, namely domestic violence, in the sense that they are similarly expressed in the context of long-term relationships between one male and one female, which are otherwise characterized by close spatial proximity and — sometimes — high levels of affiliation,” said senior author Elise Huchard of the University of Montpellier’s Institute of Evolutionary Sciences.

A female baboon presenting to a male in a form of sexual solicitation

“There is nothing paradoxical in forming a strong bond with someone, and displaying aggression in the context of such relationship,” added Huchard. “Conflict is an integral part of social life in every species including humans, and it's often with those people that you often see that you may have a conflict.”

Huchard, lead author Alice Baniel, and co-author Guy Cowlishaw studied wild chacma baboons at Tsaobis Nature Park, a semi-arid environment in Namibia. The study occurred over four different periods from 2005–2014, during which time the researchers documented 222 chases or attacks led by males.

The researchers observed that males often formed social bonds with particular fertile females, which they then attacked and chased repeatedly — usually without provocation — in the weeks preceding her ovulation and prior to their mating.

“It can also be that there is an event triggering the attack, such as a rival approaching or vocalizing, or the proximity of another baboon group,” Huchard said. “The latter case is typical: males often chase and attack some females of their own group when meeting another group, and they generally target sexually receptive females in such occasions.”

Some of the females were badly injured in the attacks, with certain individuals suffering premature deaths after repeated bouts of injuries.

The prior studies on sexual intimidation in chimps found that fertile females have higher levels of cortisol, a hormone indicative of stress. Increased stress can alter immune response. It can also disrupt reproduction and growth.

If a female baboon does give birth to offspring sired by the male, his behavior somewhat changes.

“Several studies (on baboons) have shown that it’s often the male who has been monopolizing a female during her conceptive estrus who becomes her friend when she gives birth,” Huchard explained. “The female follows the male everywhere with her newborn, and the male essentially tolerates her presence; however, studies have shown that males defend their female friend's offspring against predators or infanticidal attacks, which are not uncommon in baboons.”

She continued, “Male-female bonds progressively dissolve as infants grow towards independency, and are often finished when a female becomes fertile again, when her juvenile is fully weaned.”

A common factor among primates that practice long-term sexual intimidation is that the species tend to have males that are larger than the females. Such size differences, in turn, appear to be driven by patterns of male-to-male competition. This can happen when there are several adult males for each sexually receptive female within a population.

Since sexual coercion can stunt a victim’s growth, it might even further drive sexual size dimorphism, helping to keep the vicious cycle going.

A male baboon displaying his canines

Not all primate species have males that engage in long-term sexual intimidation, though. In lemurs, for example, it is common that females are larger than males. Even among baboons, chimps, and certainly humans, not all males practice sexual coercion.

“There is increasing research to show that animals are capable of innovations, rational decisions, self-control, empathy, strategic behavior, etc.,” Huchard said. “So, it's possible that male baboons are just driven by their sexual hormones, but it's also very possible that their actions are strategic and adjusted to the social context.”

Read more at Discovery News

Probing psychopathic brains

Psychopaths' brains are wired in a way that leads them to over-value immediate rewards and neglect the future consequences of potentially dangerous or immoral actions, research concludes.

Josh Buckholtz wants to change the way you think about psychopaths -- and he's willing to go to prison to do it.

An Associate Professor of Psychology, Buckholtz is the senior author of a study that relies on brain scans of nearly 50 prison inmates to help explain why psychopaths make poor decisions that often lead to violence or other anti-social behavior.

What they found, he said, is psychopath's brains are wired in a way that leads them to over-value immediate rewards and neglect the future consequences of potentially dangerous or immoral actions. The study is described in a July 5 paper in Neuron.

"For years, we have been focused on the idea that psychopaths are people who cannot generate emotion and that's why they do all these terrible things," Buckholtz said. "But what what we care about with psychopaths is not the feelings they have or don't have, it's the choices they make. Psychopaths commit an astonishing amount of crime, and this crime is both devastating to victims and astronomically costly to society as a whole.

"And even though psychopaths are often portrayed as cold-blooded, almost alien predators, we have been showing that their emotional deficits may not actually be the primary driver of these bad choices. Because it's the choices of psychopaths that cause so much trouble, we've been trying to understand what goes on in their brains when the make decisions that involve trade-offs between the costs and benefits of action.," he continued. "In this most recent paper...we are able to look at brain-based measures of reward and value and the communication between different brain regions that are involved in decision making."

Obtaining the scans used in the study, however, was no easy feat -- where most studies face an uphill battle in bringing subjects into the lab, Buckholtz's challenge was in bringing the scanner to his subjects.

The solution came in form of a "mobile" scanner -- typically used for cancer screenings in rural areas -- that came packed in the trailer of a tractor trailer. After trucking the equipment to a two medium-security prisons in Wisconsin, the team -- which included collaborators at the University of Wisconin-Madison and University of New Mexico -- would spend days calibrating the scanner, and then work to scan as many volunteers as possible as quickly as possible.

"It was a huge undertaking," he said. "Most MRI scanners, they're not going anywhere, but in this case, we're driving this inside a prison and then in very quick succession we have to assess and scan the inmates."

The team ultimately scanned the brains of 49 inmates over two hours as they took part in a type of delayed gratification test which asked them to choose between two options -- receive a smaller amount of money immediately, or a larger amount at a later time. The results of those tests were then fit to a model that allowed researchers to create a measure of not only how impulsive each participant's behavior was, but to identify brain regions that play a role in assessing the relative value of such choices.

What they found, Buckholtz said, was people who scored high for psychopathy showed greater activity in a region called the ventral striatum -- known to be involved in evaluating the subjective reward -- for the more immediate choice.

"So the more psychopathic a person is, the greater the magnitude of that striatal response," Buckholtz said. "That suggests that the way they are calculating the value rewards is dysregulated -- they may over-represent the value of immediate reward."

When Buckholtz and colleagues began mapping which brain regions are connected to the ventral striatum, it became clear why.

"We mapped the connections between the ventral striatum and other regions known to be involved in decision-making, specifically regions of the prefrontal cortex known to regulate striatal response," he said. "When we did that, we found that connections between the striatum and the ventral medial prefrontal cortex were much weaker in people with psychopathy."

That lack of connection is important, Buckholtz said, because this portion of the prefrontal cortex role is thought to be important for 'mental time-travel' -- envisioning the future consequences of actions. There is increasing evidence that prefrontal cortex uses the outcome of this process to change how strongly the striatum responds to rewards. With that prefrontal modulating influence weakened, the value of the more immediate choice may become dramatically over-represented.

"The striatum assigns values to different actions without much temporal context" he said. "We need the prefrontal cortex to make prospective judgements how an action will affect us in the future -- if I do this, then this bad thing will happen. The way we think of it is if you break that connection in anyone, they're going to start making bad choices because they won't have the information that would otherwise guide their decision-making to more adaptive ends."

The effect was so pronounced, Buckholtz said, that researchers were able to use the degree of connection between the striatum and the prefrontal cortex to accurately predict how many times inmates had been convicted of crimes.

Ultimately, Buckholtz said, his goal is to erase the popular image of psychopaths as incomprehensible, cold-blooded monsters and see them for what they are -- everyday humans whose brains are simply wired differently.

Read more at Science Daily

Fastest stars in the Milky Way are 'runaways' from another tiny galaxy

This is an artist's impression of runaway stars.

A group of astronomers have shown that the fastest-moving stars in our galaxy -- which are travelling so fast that they can escape the Milky Way -- are in fact runaways from a much smaller galaxy in orbit around our own.

The researchers, from the University of Cambridge, used data from the Sloan Digital Sky Survey and computer simulations to demonstrate that these stellar sprinters originated in the Large Magellanic Cloud (LMC), a dwarf galaxy in orbit around the Milky Way.

These fast-moving stars, known as hypervelocity stars, were able to escape their original home when the explosion of one star in a binary system caused the other to fly off with such speed that it was able to escape the gravity of the LMC and get absorbed into the Milky Way. The results are published in the Monthly Notices of the Royal Astronomical Society, and will be presented today (5 July) at the National Astronomy Meeting in Hull.

Astronomers first thought that the hypervelocity stars, which are large blue stars, may have been expelled from the centre of the Milky Way by a supermassive black hole. Other scenarios involving disintegrating dwarf galaxies or chaotic star clusters can also account for the speeds of these stars but all three mechanisms fail to explain why they are only found in a certain part of the sky.

To date, roughly 20 hypervelocity stars have been observed, mostly in the northern hemisphere, although it's possible that there are many more that can only be observed in the southern hemisphere.

"Earlier explanations for the origin of hypervelocity stars did not satisfy me," said Douglas Boubert, a PhD student at Cambridge's Institute of Astronomy and the paper's lead author. "The hypervelocity stars are mostly found in the Leo and Sextans constellations -- we wondered why that is the case."

An alternative explanation to the origin of hypervelocity stars is that they are runaways from a binary system. In binary star systems, the closer the two stars are, the faster they orbit one another. If one star explodes as a supernova, it can break up the binary and the remaining star flies off at the speed it was orbiting. The escaping star is known as a runaway. Runaway stars originating in the Milky Way are not fast enough to be hypervelocity because blue stars can't orbit close enough without the two stars merging. But a fast-moving galaxy could give rise to these speedy stars.

The LMC is the largest and fastest of the dozens of dwarf galaxies in orbit around the Milky Way. It only has 10% of the mass of the Milky Way, and so the fastest runaways born in this dwarf galaxy can easily escape its gravity. The LMC flies around the Milky Way at 400 kilometres per second and, like a bullet fired from a moving train, the speed of these runaway stars is the velocity they were ejected at plus the velocity of the LMC. This is fast enough for them to be the hypervelocity stars.

"These stars have just jumped from an express train -- no wonder they're fast," said co-author Rob Izzard, a Rutherford fellow at the Institute of Astronomy. "This also explains their position in the sky, because the fastest runaways are ejected along the orbit of the LMC towards the constellations of Leo and Sextans."

The researchers used a combination of data from the Sloan Digital Sky Survey and computer simulations to model how hypervelocity stars might escape the LMC and end up in the Milky Way. The researchers simulated the birth and death of stars in the LMC over the past two billion years, and noted down every runaway star. The orbit of the runaway stars after they were kicked out of the LMC was then followed in a second simulation that included the gravity of the LMC and the Milky Way. These simulations allow the researchers to predict where on the sky we would expect to find runaway stars from the LMC.

"We are the first to simulate the ejection of runaway stars from the LMC -- we predict that there are 10,000 runaways spread across the sky," said Boubert. Half of the simulated stars which escape the LMC are fast enough to escape the gravity of the Milky Way, making them hypervelocity stars. If the previously known hypervelocity stars are runaway stars it would also explain their position in the sky.

Massive blue stars end their lives by collapsing to a neutron star or black hole after hundreds of millions of years and runaway stars are no different. Most of the runaway stars in the simulation died 'in flight' after being kicked out of the LMC. The neutron stars and black holes that are left behind just continue on their way and so, along with the 10,000 runaway stars, the researchers also predict a million runaway neutron stars and black holes flying through the Milky Way.

Read more at Science Daily

West Antarctic Ice Sheet loss over the last 11,000 years seen in new study

Sediment cores were collected from Pine Island Bay in West Antarctica using the German research vessel RV Polarstern.

Reporting in the journal Nature, an international team of researchers led by British Antarctic Survey (BAS) explains that wind-driven incursions of warm water forced the retreat of glaciers in West Antarctica during the past 11,000 years. These new results enable researchers to better understand how environmental change may impact future sea-level rise from this climate-sensitive region.

By studying tiny shells in seafloor sediment cores retrieved from Pine Island Bay in West Antarctica, the team has reconstructed the interactions between the ice and ocean from 11,000 years ago until present. They describe the West Antarctic Ice Sheet (WAIS) as having experienced significant and sustained ice loss until 7,500 years ago, driven by warm water incursions. The influx of warm water then subsided for several thousands of years until it was reinvigorated in the 1940s, driving further retreat.

The WAIS is of great interest to researchers as two of its largest glaciers, Thwaites and Pine Island, are draining into the sea and contributing to sea-level rise. The big questions are why, and by how much, and what may happen in the future under climate change.

Lead author Dr Claus-Dieter Hillenbrand senior marine geologist at BAS says: "This ten-year study has yielded some exciting results. By understanding the mechanisms that caused the retreat of the WAIS over the past several thousand years, we can begin to build a clearer picture of what is happening today."

Data collected over the last 20 years have shown that the present ice loss in West Antarctica results from the relatively warm water from the deep ocean flowing on to the shallow continental shelf. This warm water reaches the coastline in places, where it triggers substantial melting of the floating parts of glaciers and leads to thinning of the ice upstream.

Dr Hillenbrand continues: "Our reconstruction shows that warm deep water flooded Pine Island Bay at the end of the last ice age. It forced the ice to retreat but stopped at about 7,500 years ago, when the belt of westerly winds driving the deep water onto the shelf shifted northwards.

"Ice loss from this part of West Antarctica is already making a significant contribution to sea-level rise -- around 1 mm per decade, and is actually one of the largest uncertainties in global sea-level rise predictions. Whilst this is a small figure in actual terms, combined with the contribution from other melting glaciers around the world and expansion of the world's oceans, it will have an impact upon society through flooding of low-lying coastal regions."

"Understanding what happened in the distant past provides another important part of the jigsaw. Computer model simulations have suggested that ice-sheet melting through warm water incursions could initiate a collapse of the WAIS within the next few centuries, raising global sea-level by up to 3.5 metres."

The team investigated sediment cores collected from Pine Island Bay in the Amundsen Sea from the German research vessel RV Polarstern on two expeditions in 2006 and 2010. The team analysed the chemical composition of tiny shells built by organisms (foraminifera) that had lived in the water column and at the sea bottom before their shells became embedded in the seafloor sediments. This chemical composition acts as a 'fingerprint' of the water that the shells were formed in. By comparing these shells with those of modern shells bathed in warm deep water today the researchers were able to identify time intervals when warm deep water was either present or absent.

Co-author Dr James Smith, a marine geologist at BAS, says: "Our data also reveal a more recent history of the WAIS. A shift in the wind direction during the 1940s caused renewed upwelling of warm deep water on to the shelf. This has continued ever since and is responsible for the ice loss we are observing today and over the last few decades."

Co-author Dr Gerhard Kuhn, from the Alfred Wegener Institute in Germany, says: "Our results provide evidence that in the past WAIS retreat was also predominantly caused by melting through warm ocean water. This gives confidence in the predictions of the current generation of ice-sheet models which are used to forecast future ice loss from Antarctica and resulting sea-level rise."

Read more at Science Daily

Why does a Yellowstone microorganism prefer meager rations over rich ones?

In Yellowstone National Park's Dragon Spring, part of the Norris Geyser Basin, scientists have found a microorganism that behaved in an unexpected way.

Arizona State University geoscientist Everett Shock has collaborated with a team of life scientists from Montana State University to discover a puzzle at the junction of geochemistry and biology.

The puzzle, which has no solution yet, is: Why would a microorganism thriving in a hot spring draw its energy from low-quality sources instead of rich ones?

Shock, who is a professor in geochemistry in ASU's School of Earth and Space Exploration and the School of Molecular Sciences, has long studied questions of habitability as they apply to life on Earth, and to the potential for life on other planets.

"The team isolated this organism, which is a member of the Acidianus genus, from a hot spring in Yellowstone National Park and cultured it in the laboratory," he said. "There it was given a choice of three different geochemical energy supplies."

This microbe, Shock said, can get energy from combining hydrogen with sulfur, or hydrogen with iron, or sulfur with iron. In the experiments the team carried out, hydrogen and sulfur supplied the least energy, while hydrogen and iron provided the most.

"Surprisingly, the organism grew best on the lowest energy supply -- and it grew the worst with the richest energy material," Shock said.

The scientists' report was published July 3 in Nature Geoscience. The lead author is Maximiliano Amenabar of Montana State University; besides Shock, the other authors are Eric Roden (University of Wisconsin), and John Peters and Eric Boyd (both Montana State).

Rich diet: Genetically costly?

"The results were quite counterintuitive," said Shock. "It's only natural to expect that in any environment, the 'big deal' energy sources will be supporting the most organisms, and the feeble sources -- well, you wonder if they are supporting anything at all."

It turns out, he explained, that in a genetic sense, it may be costly for the organism to go after the big-energy supply.

"It's like mining," he said. "You can have a rich ore deposit, but if extracting it costs more than you can get for it, it's not worth pursuing."

And in microorganism terms, Shock said, "biological cost may come down to availability. Perhaps the low-energy source is more reliable in nature than the high-energy one."

Shock suggested that reliability could "tune" the microorganism's metabolism to the energy source that's always available.

But apparently not exclusively, he added. "The organism is also capable of using these other energy sources. However, maybe using them takes more work, so the organism grows more slowly with them."

The focus of future research on this organism will be to assess in detail its energy costs. A recently completed genome for it will aid the research.

Read more at Science Daily

Shocking case of indigestion in supermassive black hole

Left: Image of the Whirlpool galaxy and NGC 5195. Credit: Jon Christensen. Right: False colour image of NGC 5195 created by combining the VLA 20 cm radio image (red), the Chandra X-ray image (green), and the Hubble Space telescope H-alpha image (blue). The image shows the X-ray and H-alpha arcs, as well as the radio outflows from the supermassive black hole at the centre of NGC 5195. Right inset: e-MERLIN maps of the nuclear region of NGC 5195 at 1.4 GHz (left) and 5 GHz (right). The images display a partially resolved source with possible parsec-scale outflows.

A multi-wavelength study of a pair of colliding galaxies has revealed the cause of a supermassive black hole's case of 'indigestion'. Results will be presented by Dr Hayden Rampadarath at the National Astronomy Meeting at the University of Hull.

Once every couple of hundred million years, the small galaxy NGC 5195 falls into the outer arms of its larger companion, NGC 5194, also known as the Whirlpool galaxy. Both galaxies are locked in a gravitational dance that will result -- billions of years in the future -- in the formation of a single galaxy.

As NGC 5195 plunges into the Whirlpool, matter streams onto the supermassive black hole at NGC 5195's centre and forms an accretion disc. The disc grows to a point where the supermassive black hole can no longer accrete or 'digest' efficiently and matter is blasted out into the surrounding interstellar medium. Last year, NASA's Chandra X-Ray observatory spotted arcs of X-ray emission that appeared to result from this 'force-feeding'.

Now, new high-resolution images of the core of NGC 5195, taken with the e-MERLIN radio array, and archive images of the surrounding area from the Very Large Array (VLA), Chandra and the Hubble Space Telescope, reveal in detail how these blasts occur and spread. The study was led by astronomers at the University of Manchester's Jodrell Bank Centre for Astrophysics.

The supermassive black hole at the centre of NGC 5195 has a mass equivalent to 19 million Suns. When the accretion process breaks down, immense forces and pressures create a shock wave that pushes matter out into the interstellar medium. Electrons, accelerated close to the speed of light, interact with the magnetic field of the interstellar medium and emit energy at radio wavelengths. The shock wave then inflates and heats up the interstellar medium, which emits in the X-ray, and strips the electrons from surrounding neutral hydrogen atoms to make ionised hydrogen gas. This inflated bubble creates the arcs detected by Chandra and Hubble.

Rampadarath explains: "Comparing the VLA images at radio wavelengths to Chandra's X-ray observations and the hydrogen-emission detected by Hubble, shows that features are not only connected, but that the radio outflows are in fact the progenitors of the structures seen by Chandra and Hubble. This is an event of galactic proportions that we can see right across the electromagnetic spectrum."

Read more at Science Daily

Dinosaurs' loss was frogs' gain: The upside of a mass extinction

The frog Hyla sanchiangensis from eastern China is a descendant of one of three lineages (Hyloidea) that made it through Earth's last mass extinction 66 million years ago to flourish worldwide today. It's ancestors diversified out of South America.

Most of the frogs alive today owe a big thank you to the asteroid or comet that delivered the coup de grace to the dinosaurs.

A new study by Chinese and American biologists shows that if the calamity had not wiped the planet clean of most terrestrial life 66 million years ago, 88 percent of today's frog species wouldn't be here. Nearly nine out of 10 species of frog today have descended from just three lineages that survived the mass extinction.

The results, to be published this week in the journal Proceedings of the National Academy of Sciences, are a surprise, because previous studies of frog evolution pinpointed the blossoming of the main frog lineages today to about 35 million years earlier, in the middle of the Mesozoic era.

The new analysis of 95 genes from frogs within 44 of 55 living families shows that these three lineages started to take off precisely at the boundary between the Cretaceous and Paleogene periods -- the K-Pg boundary, formerly called the KT boundary -- when the last mass extinction occurred, and not 100 million years ago.

According to herpetologist and co-author David Wake, a University of California, Berkeley professor of the graduate school and a curator of the Museum of Vertebrate Zoology, new frog species likely radiated rapidly throughout the world because so many environmental niches were available after the animals occupying them disappeared.

"We think the world was quite impoverished as a result of the KT event, and when the vegetation came back, angiosperms dominated. That's when trees evolved to their full flowering," Wake said. "Frogs started becoming arboreal. It was the arboreality that led to the great radiation in South America in particular."

Trees are an ideal habitat for frogs not only because they allow them to escape from terrestrial predators, but also because their fallen leaves provide protection while the frogs are on the ground, breeding habitat and plenty of food, such as insects. Trees and other flowering plants took off in the late Cretaceous, and were ready for exploitation by frogs after they recovered from the extinction.

Another adaptation that became popular was direct development, that is, producing young without a tadpole stage, which is standard for about half of all frog species today.

"The majority of the frogs that thrive now are thriving because of direct development of eggs in terrestrial situations," he said. "It is a combination of direct development and use of arboreal habitat that accounts for a great deal of the radiation."

Previous genetic analyses of frog evolution focused on mitochondrial DNA and how long the molecular clock had been ticking for mitochrondrial genes. However, analysis of molecular evolution in mitochondrial DNA often produces dates for lineage divergence that are too old. In the case of frogs, such analysis pinpointed the radiation of most living frogs at about 100 million years ago, which was a puzzle, since Earth's environment was stable at that time. A changing environment typically drives evolution.

The new analysis, based on data assembled primarily by graduate student Yan-Jie Feng at Sun Yat-Sen University in Guangzhou, China, focused on the sequences of 95 genes located on chromosomes in the nucleus and how they changed over time. He and his colleagues gathered genetic data from 156 frog species and combined this with earlier information about two genes from 145 different frogs, for a total of 301 distinct frog species from all 55 families of frogs. The data were calibrated using 20 dates derived from fossils and Earth historical events.

The team, which includes scientists from the Florida Museum of Natural History at the University of Florida and the University of Texas, Austin, concluded that perhaps 10 groups of frogs survived the extinction, but only three of them (Hyloidea, Microhylidae, and Natatanura) flourished and diversified to claim habitats and niches around the world.

Nothing other than luck distinguishes the survivors, Wake said. Remnants of the other surviving lineages are scattered in isolated spots around the world, but are just as diverse today in their habitats and breeding strategies as the 88 percent.

Two of the three surviving lineages that subsequently radiated widely came out of Africa, which remained intact as the continents shifted around over the ensuing eons, with the breakup of Pangea and then Gondwana to form the continents we see today. The African rift zone and mountain building in West Africa generated new habitats for the evolving frogs, Wake noted. The third, Hyloidea, radiated throughout what became South America.

Today's frogs, comprising more than 6,700 known species, as well as many other animal and plant species are under severe stress around the world because of habitat destruction, human population explosion and climate change, possibly heralding a new period of mass extinction. The new study provides one clear message for future generations.

Read more at Science Daily

Through fossil leaves, a step towards Jurassic Park

Ginkgo fossil.

For the first time, researchers have succeeded in establishing the relationships between 200-million-year-old plants based on chemical fingerprints. Using infrared spectroscopy and statistical analysis of organic molecules in fossil leaves, they are opening up new perspectives on the dinosaur era.

The unique results stem from a collaboration between researchers at Lund University, the Swedish Museum of Natural History in Stockholm, and Vilnius University.

"We have solved many questions regarding these extinct plants' relationships. These are questions that science has long been seeking answers to," says Vivi Vajda, a professor at the Department of Geology at Lund University and active at the Swedish Museum of Natural History.

The researchers have collected fossil leaves from rocks in Sweden, Australia, New Zealand and Greenland. Using molecular spectroscopy and chemical analysis, the fossil leaves were then compared with the chemical signatures from molecules in plant leaves picked at the Botanical Garden in Lund.

The use of genetic DNA analysis in modern research to determine relationships is not possible on fossil plants. The oldest DNA fragments ever found are scarcely one million-years-old. Therefore, the scientists searched for organic molecules to see what these could reveal about the plants' evolution and relationships.

The molecules were found in the waxy membrane, which covers the leaves and these showed to differ between various species. The membrane has been preserved in the fossil leaves, some of which are 200 million-years-old.

Using infrared spectroscopy, the researchers carried out analyses in several stages. Firstly, they examined leaves from living plants that have relatives preserved in the fossil archive. The analysis showed that the biomolecular signatures were similar among plant groups, much in the same way as shown by modern genetic DNA analysis.

When the method was shown to work on modern plants, the researchers went on to analyse their extinct fossil relatives. Among others, they examined fossil leaves from conifers and several species of Ginkgo. The only living species of Ginkgo alive today is Ginkgo biloba, but this genus was far more diverse during the Jurassic.

"The results from the fossil leaves far exceeded our expectations, not only were they full of organic molecules, they also grouped according to well-established botanical relationships, based on DNA analysis of living plants i.e. Ginkgoes in one group, conifers in another," says Vivi Vajda.

Finally, when the researchers had shown that the method gave consistent results, they analysed fossils of enigmatic extinct plants that have no living relatives to compare them with Among others, they examined Bennettites and Nilssonia, plants that were common in the area that is now Sweden during the Triassic and Jurassic around 250-150 million years ago. The analysis showed that Bennettites and Nilssonia are closely related. On the other hand, they are not closely related to cycads, which many researchers had thought until now.

Per Uvdal, Professor of Chemical Physics at Lund University and one of the researchers who conducted the study, considers that the overall results are astounding.

"The great thing about the biomolecules in the leaves' waxy membranes is that they are so much more stable than DNA. As they reflect, in an indirect way, a plants DNA they can preserve information about the DNA. Therefore, the biomolecules can tell us how one plant is related in evolutionary terms to other plants," he says.

Read more at Science Daily

An Enormous Crocodile with T. rex Teeth Was a Top Jurassic Predator

An artistic depiction of Razanandrongobe sakalavae scavenging on a sauropod carcass during the Middle Jurassic epoch in Madagascar. Unlike extant crocodilians, this terrestrial predator had a deep skull and walked on erect limbs.

The Jurassic period is often called the Age of the Ruling Reptiles, and for good reason. In the seas, aquatic reptiles such as the dolphin-like Stenopterygius were plentiful. In the air, flying reptiles known as pterosaurs searched for prey. On land, huge dinosaurs like Stegosaurus and meat-hungry Ceratosaurus had a commanding presence.

An important new addition to the list of ruling reptiles is Razanandrongobe sakalavae, or Razana for short. This gigantic crocodile, described in the journal PeerJ, was at the top of the Middle Jurassic food chain 164­–167 million years ago, and provides evidence that some crocodiles could take on even the fiercest dinosaur predators.

First known from a few teeth found a decade ago, Razana is now better understood due to recent analysis of additional cranial remains.

“We began with a couple of isolated teeth and ended up bringing back to life a one-ton terrifying bone crusher,” lead author Cristiano Dal Sasso of the Natural History Museum of Milan said.

He and colleagues Giovanni Pasini, Guillaume Fleury, and Simone Maganuco pieced together Razana based on fossils that include deep, massive jaw bones topped with large serrated teeth. The teeth were similar in size and shape to those of Tyrannosaurus rex, which is estimated to have exerted one of the largest bite forces among all terrestrial animals. At some 40 feet in length, T. rex was also an extremely large carnivore in its Late Cretaceous environment.

Paleontologists Cristiano Dal Sasso (left) and Simone Maganuco (right) standing next to the jaws of “Razana” at the Natural History Museum of Milan.

Razana, which lived close to 100 million years before T. rex, was 23 feet long. But it weighed an estimated 2,205 pounds and had erect legs, as opposed to the very low-to-the-ground limbs of modern alligators, crocodiles, and their relatives.

Its teeth and other remains suggest that Razana fed on hard tissues, such as bones and tendons. As a result, the researchers believe it could successfully bite into almost any animal — alive or dead.

“Razana was probably an opportunistic animal, just like hyenas and lions,” Dal Sasso said, adding that it was “not a very fast runner, but it was an ambush predator and a scavenger” that “could probably swim, just for crossing the nearby rivers, but it was built to walk on dry land.”

Its turf was a site now called the Mahajanga Basin of northwest Madagascar. Locals call the area the Sakalava region, so Razana’s full name means “giant lizard ancestor from the Sakalava region.”

Comparison between the estimated body size of the giant notosuchian crocodyliform Razanandrongobe sakalavae (nicknamed “Razana”) and a human.

The authors mention that this area is known for its “peculiar” collection of fossils representing everything from large marine reptiles called plesiosaurs to towering plant-eating dinosaurs known as sauropods.

“Madagascar was already separating from Africa, but was still connected to India, Australia and Antarctica,” Maganuco said.

Now an island nation, Madagascar remains known for its unique plant and animal life, often found nowhere else on Earth. Rare lemurs, for example, are native to Madagascar, which is also home to exotic orchids. Even crocodiles still thrive in Madagascar, with one infamous population of Nile crocodiles dwelling in caves.

Razana is long gone, but it holds a noteworthy place on the crocodile family tree. The scientists believe Razana was the largest and oldest “notosuchian,” predating other known forms of these animals by 42 million years. The term refers to certain early crocodilians and their extinct relatives. Previously, notosuchians were thought to appear in the Cretaceous, but Razana extends their dominance to the Jurassic.

While today’s crocodilians somewhat resemble Razana, much has changed due to evolution over millions of years.

“Modern crocs are well adapted to a semiaquatic lifestyle,” Maganuco said. “Their flattened skull with raised eyes is made for hunting in water.”

Paleo-artistic restoration of the head of Razanandrongobe sakalavae.

He continued that these animals today are incredible survivors, from an evolutionary standpoint. Their forerunners, such as Razana, were likely in direct competition with some of the most legendary predatory dinosaurs of all time. Some of these sturdy reptiles even managed to survive the end-Cretaceous extinction event that wiped out all dinosaurs, except for certain birds.

“The last fully terrestrial crocs lived up to the Middle Miocene about 15 million years ago, ruling the earth together with Cenozoic mammals and terror birds,” Maganuco said.

Terror birds, which could grow up to 12 feet tall, were flightless birds with ultra-sharp hooked beaks. Like Razana, they rose to the top of their food chain.

Read more at Discovery News