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Wednesday, January 18, 2017

Electrons “Puddle” Under High Magnetic Fields, Study Reveals

Olympic figure skaters and electrons have a lot in common. In figure skating competitions, the "free skate" segment gives the skater the flexibility to travel in whichever pattern he or she chooses around the rink. Similarly, in metals, electrons in outer orbitals can wander fairly freely.

However, when the magnetic field is increased dramatically, researchers have found that the motion of these electrons becomes much more tightly confined. Their behavior looks like figure skaters completing compulsory tight spins and jumps.

In a new study from the U.S. Department of Energy's (DOE's) Argonne National Laboratory, researchers used extremely high magnetic fields — equivalent to those found in the center of neutron stars — to alter electronic behavior. By observing the change in the behavior of these electrons, scientists may be able to gain an enriched understanding of material behavior.

In a new study, Argonne scientists have discovered a way to confine the behavior of electrons by using extremely high magnetic fields.
Credit: Argonne National Laboratory

"The rules of the game are changed when we apply a magnetic field of this intensity," said Argonne materials scientist Anand Bhattacharya, who led the research. "The nature of this new state that we see has been debated theoretically for over half a century, but experiments to measure its properties have been hard to come by."

To create the very high magnetic field needed, Bhattacharya used the facilities of the National High Magnetic Field Lab in Tallahassee, Florida. There, with colleague Alexey Suslov, he examined crystals of strontium titanate, similar to synthetic diamond, which has the unusual property of allowing electricity to flow even when electrons are extremely sparse and slow-moving.

The slow motion of the electrons inside the crystal makes them particularly susceptible to magnetic forces. The researchers observed that the quantum properties of the electrons changed dramatically when the crystals were put under high magnetic fields and cooled down to just a few hundredths of a degree above absolute zero.

Former Argonne postdoctoral researcher Brian Skinner (now at MIT) and former National Institutes of Standards and Technology postdoctoral researcher Guru Khalsa (now at Cornell) provided the theoretical insights that helped the researchers understand their results. They proposed that in very high magnetic fields, the electrons form spatially inhomogeneous "puddles" a surprising finding that was supported by key aspects of the data.

Although Bhattacharya is hesitant to identify new technologies that could be created to take advantage of this new material regime, he said that the result is encouraging for scientists looking to develop a fuller understanding of the unusual properties of certain materials.

"When we push the limits to which we can take electrons, new physics emerges," Bhattacharya said. "If you think about our understanding of electrons, we understand metals, where electrons move freely, and we also understand the behavior of highly localized electrons. But if you can open the door to those in-between regions, you can make new discoveries."

A paper based on the study, "Spatially inhomogeneous electron state deep in the extreme quantum limit of strontium titanate," appeared in the September 29 edition of Nature Communications. The research was funded by the U.S. Department of Energy's Office of Science. Part of the work was performed at the Center for Nanoscale Materials, a DOE Office of Science User Facility at Argonne

Contacts and sources:
Argonne National Laboratory

Milky-Way-Like Galaxies Seen in their Awkward Adolescent Years

Spiral galaxies like our own Milky Way were not always the well-ordered, pinwheel-like structures we see in the universe today. 

Astronomers believe that about 8-10 billion years ago, progenitors of the Milky Way and similar spiral galaxies were smaller, less organized, but amazingly rich in star-forming material; so much so, that they would have been veritable star factories, churning out new stars faster than at any other point in their lifetimes. Now, astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA) have found evidence to support this view. 

Four Milky-Way-like progenitor galaxies as seen as they would have appeared 9 billion years ago. ALMA observations of carbon monoxide (red) is superimposed on images taken with the Hubble Space Telescope. The carbon monoxide would most likely be suffused throughout the young galaxies.

Credit. ALMA (ESO/NAOJ/NRAO) C. Papovich; A. Angelich (NRAO/AUI/NSF); NASA/ESA Hubble Space Telescope

By studying four very young versions of galaxies like the Milky Way as they were seen approximately 9 billion years ago, the astronomers discovered that each galaxy was incredibly rich in carbon monoxide gas, a well-known tracer of star-forming gas. 

“We used ALMA to detect adolescent versions of the Milky Way and found that such galaxies do indeed have much higher amounts of molecular gas, which would fuel rapid star formation," said Casey Papovich, an astronomer at Texas A&M University in College Station and lead author on a paper appearing in Nature Astronomy. 

“I liken these galaxies to an adolescent human who consumes prodigious amounts of food to fuel their own growth during their teenage years.” Though the relative abundance of star-forming gas is extreme in these galaxies, they are not yet fully formed and rather small compared to the Milky Way as we see it today. 

The new ALMA data indicate that the vast majority of the mass in these galaxies is in cold molecular gas rather than in stars. These observations, the astronomers note, are helping build a complete picture of how matter in Milky-Way-size galaxies evolved and how our own galaxy formed.

The National Radio Astronomy Observatory is a facility of the National Science Foundation, operated under cooperative agreement by Associated Universities, Inc.

Contacts and sources:
Charles Blue
The National Radio Astronomy Observatory

Fossils Found Reveal Unseen 'Footprint' Maker

Fossils found in Morocco from the long-extinct group of sea creatures called trilobites, including rarely seen soft-body parts, may be previously unseen animals that left distinctive fossil ‘footprints’ around the ancient supercontinent Gondwana.

The trilobites were a very common group of marine animals during the 300 million years of the Palaeozoic Era with hard, calcified, external armour-like skeletons over their bodies. They disappeared with a mass extinction event about 250 million years ago which wiped out about 96% of all marine species.

Fossil of Megistaspis trilobite with preserved digestive structures: crop and intestine with digestive caeca.

Credit: University of Adelaide

University of Adelaide-led research published in the journal Scientific Reports describes three specimens of the 480 million-year-old trilobite Megistaspis (Ekeraspis) hammondi, up to 30 centimetres long and with preserved soft-parts showing a unique combination of digestive structures and double-branched legs.

“One of the most striking aspects of the discovery is that the first three pairs of legs, those located in the head, bear short, strong spines, while those further back in the thorax and tail are smooth,” says Dr Diego García-Bellido, ARC Future Fellow with the University of Adelaide’s Environment Institute and South Australian Museum.

“We believe this specialised type of legs are the ones that produced the fossil traces named Cruziana rugosa, thought to be from a trilobite but the actual trace-maker was previously unknown. These marine animals ploughed the sediment in the sea floor for food with their forward legs, while holding their heads tilted downward, leaving behind a double groove with parallel scratches made by the spines on the legs.

An illustration of a trilobite (a different species than the recent find)

Credit: Image by Diego García-Bellido

“The legs we can see on these new fossils match the traces we’ve known as Cruziana rugosa.”

Dr García-Bellido, Juan Gutiérrez-Marco of the Spanish National Research Council and colleagues present for the first time the preserved gut with associated digestive structures plus a complete set of both branches of the trilobite legs.

Cruziana species are one of the most abundant trace fossils found in the lower Palaeozoic sediments across Gondwana but little was known of the particular process producing the distinct Cruziana rugosa traces, where imprints are aligned in sets of up to 12 parallel scratches.

The digestive structures seen also include a unique combination of features: a ‘crop’ together with several pairs of digestive glands or caeca in the upper parts of the digestive system. Other trilobite fossils have been seen with either a crop or the paired digestive caeca but, until now, they have never been found together. 

Fossil of Megistaspis trilobite showing the legs of one side: those on the head (legs 1–3) carrying short strong spines (yellow arrowheads), while those on the thorax (legs 4, 5) are smooth.

Credit: University of Adelaide

Trilobites have three main parts: a head with eyes, antennae, mouth, and three pairs of appendages or legs; a thorax with many joined segments, each bearing a pair of legs; and a tail with a number of fused segments and several pairs of legs. Trilobite appendages are soft, with an outer branch which is a gill, and an inner branch used for walking and feeding. The preservation of their soft-body is extremely rare, restricted to only a couple of dozen cases, because their external ‘skin’ and internal anatomy was normally lost through scavenging and decay soon after death, or overprinted by the mineralised exoskeleton.

The research involved collaboration between the University of Adelaide/South Australian Museum, the Spanish Research Council and Spanish Geological Survey, and the Universities of Vila Real and Coimbra in Portugal.

Contacts and sources:
Dr Diego Garcia-Bellido
Ms Robyn Mills
University of Adelaide

ALMA Reveals The Sun in New Light

New images from the Atacama Large Millimeter/submillimeter Array (ALMA) reveal stunning details of our Sun, including the dark, contorted center of an evolving sunspot that is nearly twice the diameter of the Earth.

These images are part of the testing and verification campaign to make ALMA's solar observing capabilities available to the international astronomical community. 

This ALMA image of an enormous sunspot was taken on 18 December 2015 with the Band 6 receiver at a wavelength of 1.25 millimeters. Sunspots are transient features that occur in regions where the Sun’s magnetic field is extremely concentrated and powerful. They are lower in temperature than their surrounding regions, which is why they appear relatively dark in visible light.
The ALMA image is essentially a map of temperature differences in a layer of the Sun's atmosphere known as the chromosphere, which lies just above the visible surface of the Sun (the photosphere). The chromosphere is considerably hotter than the photosphere. Understanding the heating and dynamics of the chromosphere are key areas of research that will be addressed by ALMA. Observations at shorter wavelengths probe deeper into the solar chromosphere than longer wavelengths. Hence, band 6 observations map a layer of the chromosphere that is closer to the visible surface of the Sun than band 3 observations. 

ALMA tested its solar-observing capabilities by making a series of images of the Sun. From single-dish images of the entire solar disk to a close-up view of an evolving sunspot, these images provide new insights into the dynamics of our nearest star. 
Written and Narrated by Charles Blue (NRAO/AUI/NSF)
Produced by Alexandra Angelich (NRAO/AUI/NSF)
Additional Animation and Image Credits: ALMA (ESO/NAOJ/NRAO); B. Saxton, J. Hellerman, M. Kaufman, and A. Isella (NRAO/AUI/NSF); HST (ESA/NASA); SOHO (ESA/NASA)
Music: Mark Mercury

Though designed principally to observe remarkably faint objects throughout the universe -- such as distant galaxies and planet-forming disks around young stars – ALMA is also capable of studying objects in our own solar system, including planets, comets, and now the Sun.

ALMA image of an enormous sunspot taken on 18 December 2015 with the Band 3 receiver at a wavelength of 3 millimeters. Sunspots are transient features that occur in regions where the Sun’s magnetic field is extremely concentrated and powerful. They are lower in temperature than their surrounding regions, which is why they appear relatively dark in visible light. The ALMA images are essentially maps of temperature differences in a layer of the Sun's atmosphere known as the chromosphere, which lies just above the visible surface of the Sun (the photosphere). 

The chromosphere is considerably hotter than the photosphere. Understanding the heating and dynamics of the chromosphere are key areas of research that will be addressed by ALMA. Observations at shorter wavelengths probe deeper into the solar chromosphere than longer wavelengths. Hence, band 6 observations map a layer of the chromosphere that is closer to the visible surface of the Sun than band 3 observations.

During a 30-month period beginning in 2014, an international team of astronomers harnessed ALMA's single-antenna and array capabilities to detect and image the millimeter-wavelength light emitted by the Sun’s chromosphere -- the region that lies just above the photosphere, the visible surface of the Sun. 

This full map of the Sun at a wavelength of 1.25 mm was taken with a single ALMA antenna using a so-called "fast-scanning" technique. The accuracy and speed of observing with a single ALMA antenna makes it possible to produce a low-resolution map of the entire solar disk in just a few minutes. Such images can be used in their own right for scientific purposes, showing the distribution of temperatures in the chromosphere, the region of the solar atmosphere that lies just above the visible surface of the Sun.


These new images demonstrate ALMA’s ability to study solar activity at longer wavelengths than observed with typical solar telescopes on Earth, and are an important expansion of the range of observations that can be used to probe the physics of our nearest star.

"We’re accustomed to seeing how our Sun appears in visible light, but that can only tell us so much about the dynamic surface and energetic atmosphere of our nearest star,” said Tim Bastian, an astronomer with the National Radio Astronomy Observatory in Charlottesville, Va. "To fully understand the Sun, we need to study it across the entire electromagnetic spectrum, including the millimeter and submillimeter portion that ALMA can observe." 

This image of the entire Sun was taken at a wavelength of 617.3 nanometers. Light at this wavelength originates from the visible solar surface, the photosphere. A cooler, darker sunspot is clearly visible in the disk, and -- as a visual comparison -- a depiction from ALMA at a wavelength of 1.25 millimeters is shown.

Credit: ALMA (ESO/NAOJ/NRAO); B. Saxton (NRAO/AUI/NSF) Full-disc solar image: Filtergram taken in Fe I 617.3 nm spectral line with the Helioseismic and Magnetic Imager (HMI) onboard the Solar Dynamics Observatory (SDO). Credit: NASA

Since our Sun is many billions of times brighter than the faint objects ALMA typically observes, the solar commissioning team had to developed special procedures to enable ALMA to safely image the Sun.

The result of this work is a series of images that demonstrates ALMA’s unique vision and ability to study our Sun on multiple scales.

The National Radio Astronomy Observatory is a facility of the National Science Foundation, operated under cooperative agreement by Associated Universities, Inc.

Contacts and sources: 
Charles Blue
The National Radio Astronomy Observatory

Now Drivers Will Hear Ambulances No Matter How Loud Their Music Is Playing

If you’ve ever been startled by the sudden appearance of an ambulance while blasting music in your car, then you appreciate the value of a loud siren. Fortunately, your car is probably equipped already to receive warning signals on its audio system, thanks to a new solution developed by students in Sweden.

In Stockholm, ambulances will soon be piloting a system that interrupts whatever you’re listening to – be it CDs, Bluetooth or the radio – and broadcasts a voice warning that an emergency vehicle is heading your way.

You may never have to worry about not hearing ambulance sirens again - Swedish drivers will soon get audio warnings that interrupt their music, as well as a text, when an ambulance is approaching.
Credit:  KTH Royal Institute of Technology

Developed by students at KTH Royal Institute of Technology in Stockholm, the solution involves a radio transmission from the emergency vehicle to nearby FM tuners that are equipped with Radio Data System (RDS).

The signal is sent over the FM band along with the transmission of a text message that appears in the tuner display, says Florian Curinga, one of three students at KTH who developed the solution – called EVAM System.

Crashes involving motorists who didn’t hear sirens are becoming more common thanks to improvements in sound insulation, Curinga says.

“Often drivers have only a few seconds to react and give way to emergency vehicles,” says Curinga’s partner, Mikael Erneberg, who also studies industrial engineering at KTH. “The optimal warning time is at least 10 to 15 seconds.”

Stockholm will begin testing their system in a limited number of emergency vehicles beginning in Q1 2017. “We want to catch motorists' attention at an early stage, and mitigate stress that impairs road safety,” Erneberg says.

As long as the tuner is turned on, a voice message will broadcast on the system. Unlike lights and sirens, the warning system anticipates how far in advance messages need to be heard depending on the speed of local traffic. On a highway, for example, the signal will broadcast earlier than in slow city traffic.

Curinga says that the EVAM System would reach two-thirds of all vehicles on the road, and it can also warn of accidents along the route.

“It fulfills three functions: improving accessibility for first responders, improving road safety and make the working environment in transport better for vulnerable professions,” he says.

Contacts and sources:
KTH Royal Institute of Technology

Inception of the Last Ice Age

The Eurasian ice sheet was the third largest ice mass during the Last Glacial Maximum some 22,000 years ago. Alongside the Antarctic and North American ice sheets it lowered the global sea level by more than 120 metres. In volume it was almost three times greater than the modern day Greenland ice sheet.

At its peak there was continuous ice cover from present-day Ireland, across Scandinavia and all the way through to western Siberia in the Russian High Arctic.

The Late Weichselian Eurasian Ice Sheet Complex (EISC; red outline) in the context of Northern Hemispheric glaciation. The EISC comprised three semi-independent ice-sheets, though maximum extension in all sectors was not contemporaneous.

Illustration: Henry Patton.

The results are published in Quaternary Science Reviews (Open access)

Three ice caps that merged

It all started some 37,000 years ago when the planet's climate started getting colder. This process happened as part of the natural climate cycles on our planet, which are linked to Earth's movements around the sun and around its own axis. For the last million years or so these cycles have repeated consistently every 100,000 years: 90,000 years of ice age followed by a roughly 10,000 year interglacial warm period.

Time slices from the model show the development of the ice sheet. It starts out as three independent, distinct ice masses: Celtic, Fennoscandian and Barents Sea. These eventually merge to form one large ice sheet complex.
Illustration: Henry Patton.

"The Eurasian Ice Sheet started life off as a number of small and isolated ice caps scattered across Europe and the Arctic. Through time, and with the climate getting increasingly colder this ice grew, with the ice caps eventually merging together to form one coherent ice sheet. The weight of this ice was sufficient to warp the Earth's crust, making dramatic changes to the coastline." says Patton.

It is a slow process from human perspective, but from a geological point of view things do happen quite quickly: within 6,000 years these individual ice sheets were large enough to develop fast-flowing ice streams, and within 13,000 years they merged into one continuous ice mass.

Twice the Mediterranean

"By itself it lowered global sea level by more than 17 metres. However, despite its global influence, attempts to understand the climatic and oceanographic drivers behind its growth have remained poorly resolved." says postdoc Henry Patton from the Centre for Arctic Gas Hydrate, Environment and Climate (CAGE)

Until now, that is. Patton and colleagues have recently published comprehensive, high-resolution model experiments, detailing the inception and evolution of the Eurasian ice sheet from its first steps 37,000 years ago through to its maximum extent some 15,000 years later.

Time slices from the model show the development of the ice sheet. It starts out as three independent, distinct ice masses: Celtic, Fennoscandian and Barents Sea. These eventually merge to form one large ice sheet complex.

Credit: Henry Patton

They calculated that by that time the ice sheet had grown to a massive volume of more than 7 million cubic kilometres - twice the volume of the Mediterranean Sea. It had an average ice thickness of more than 1.3 km.

"Our model allows us to appreciate the complexities and sensitivities of such a vast ice sheet. The climate that made this ice complex grow was significantly different to the climate we experience today. The issue is further complicated by the fact that once an ice sheet grows large enough, it also begins to heavily influence the regional climate patterns around it."

Wet in the west, desert in the east

It takes more than just cold temperatures to make an ice sheet grow. It also depends a lot on the amount of snowfall, which enables the ice sheet to accumulate mass. Then, as today, Norway, Britain and Ireland were subject to relatively wet, maritime conditions, with the coastal mountains becoming the perfect setting for ice accumulation.

"Snowfall is a key factor for making an ice sheet grow. In the case of the Eurasian ice sheet complex, snowfall across the mountains of Western Europe was vital for allowing the various ice caps to initially expand."

The Eurasian ice sheet had an enormous influence on the climate at the continental scale: it absorbed precipitation to such an extent that it created a rain-shadow effect effectively turning much of western Russia and Siberia into a frozen desert where glaciers could not grow.

"As the ice sheet grew thicker, less and less precipitation was able to reach the lee areas east of the complex. This created desert conditions similar to what we see in the Dry Valleys of Antarctica today." Patton explains.

Traces on the ocean floor

Successfully reconstructing the evolution of an ice sheet through millennia depends on the quality and abundance of observational data available. Distributions of glacial sediments, radiocarbon dates, and geological features found on the landscape are all examples of data that can help guide modelling experiments. As the ice moved it also left traces on the ocean floor.

"Perhaps the most important advance to have aided this modelling work is the quantity and quality of geophysical data from beneath marine areas that we now have access too. Only 10-15 years ago we had a very limited understanding of what Eurasian ice was doing offshore, particularly in the Barents and Kara seas."

Time slices from the model show the development of the ice sheet. It starts out as three independent, distinct ice masses: Celtic, Fennoscandian and Barents Sea. These eventually merge to form one large ice sheet complex

Credit: Henry Patton

Major portions of this ice sheet were grounded below sea level, just like in West Antarctica today. Understanding the climatic and oceanographic sensitivities of this Eurasian ice sheet, and how it impacted the environment, is thus important also for our present-day ice sheets.

The next step for Patton and colleagues will be to model the collapse of this Eurasian ice-sheet.

"One of the major questions facing us today is how the present ice sheets in Greenland and Antarctica will react to climate change. Simply put, the more we understand of the mechanisms that drove ice sheets to collapse in the past, the better we will be able to predict what will happen in the future."

Contacts and sources:
Henry Patton
CAGE - Center for Arctic Gas Hydrate, Climate and Environment

Citation: Patton, H., Hubbard. A., Andreassen, K., Winsborrow, M., Stroeven, P. A. (2016) The build-up, configuration, and dynamical sensitivity of the Eurasian ice-sheet complex to Late Weichselian climatic and oceanic forcing. Quaternary Science Reviews. Volume 153, 1 December 2016, Pages 97-121. doi.org/10.1016/j.quascirev.2016.10.009 http://dx.doi.org/10.1016/j.quascirev.2016.10.009

Presumed Young Star Turns Out to Be a Galactic Senior Citizen

It was considered a teenager among the stars. But now one thing has become clear: this celestial object was formed when our galaxy was born. Why did researchers get it wrong for many decades?

49 Lib, a relatively bright star in the southern sky, is twelve billion years old rather than just 2.3 billion. For many decades, researchers were stumped by conflicting data pertaining to this celestial body, because they had estimated it as much younger than it really is. Determining its age anew, astronomers at Ruhr-Universität Bochum (RUB) have now successfully resolved all inconsistencies. Dr Klaus Fuhrmann and Prof Dr Rolf Chini published their results in the “Astrophysical Journal”.

Rolf Chini has been researching approximately 400 stars in the vicinity of the sun that share some of the sun’s properties for many years. In the process, he and his team have made a very interesting discovery.
Credit: © RUB, Nelle

“It had previously been assumed that the star was only half as old as our sun,” says Chini. “However, our data have shown that it had been formed at the time that our galaxy was born.” The reason for the error: the celestial object is a dual star system, as was proved by another research group in 2016. Chini’s team has now demonstrated the mechanism used by the star partner of 49 Lib to fake its age.

Invisible star companion

The partner of 49 Lib is an almost extinguished star that is as good as invisible. At the end of its life, it had transferred a part of its matter to 49 Lib – this is what had made the estimation of age so confusing.

Scientists determine the age of stars based on their chemical composition. Old stars that had been formed during an early stage of the universe do not contain any heavy elements. This is because those elements were generated later, following the nuclear fusion of many generations of stars. Young stars such as our sun possess heavy elements, because they have emerged from the remnants of past generations of stars.

Giant at the close of its life

As the mysterious star 49 Lib contains heavy elements, researchers used to think for many decades that it is a relatively young celestial body. However, the team from Bochum has found out that the heavy elements did not originate on 49 Lib, but had been transferred to it from its invisible companion.

At the end of their life, stars become huge; so huge that their own gravity is no longer sufficient to keep the matter together. The matter escapes as gas into space. Should there be another star in its vicinity, its gravity might attract and absorb the expelled matter. This is how 49 Lib gained its heavy elements.

Determining the age of stars

Astronomers determine the age of stars based on their spectra. They break the light emitted by the star into its individual components and decode the wavelength at which the star emits most light. The composition of a star’s chemical elements determines the spectrum.

Based on their data, the RUB researchers did more than just specify the age of the analysed star. “We are able to track this dual system’s entire evolution,” explains Rolf Chini. The astronomers know, for example, the masses with which the star’s life had begun and how those masses have evolved since then.

From white dwarves to supernova

At first, both stars had similar mass properties as the sun. When 49 Lib took over a part of the matter of its extinguishing partner, it gained a weight of approximately 0.55 solar masses. The more mass a star, the shorter its lifespan. The weight gain has thus reduced 49 Lib’s lifespan dramatically. “It will soon become a red giant and then collapse into a white dwarf,” as Rolf Chini describes its fate.

As a red giant, 49 Lib will no longer be able to keep its matter together, undergoing the same process that its star partner underwent as it turned into a white dwarf. Part of the matter of 49 Lib will be attracted by its extinguishing star partner. “If that partner cannot rid itself of the matter in small eruptions, it will fully explode as a supernova,” says Chini.

Contacts and sources:
Prof Dr Rolf Chini
Ruhr-Universität Bochum (RUB) 
Citation: Klaus Fuhrmann, Rolf Chini: Bright times for an ancient star,  DOI: 10.3847/1538-4357/834/2/114 The Astrophysical Journal, Volume 834, Number 2

Tuesday, January 17, 2017

Neanderthals Were Rock Hounds Reveals 130,000 Year Old Stone Collection

Maybe this Neanderthal was a rock hound?

An international group that includes a University of Kansas researcher has discovered a brownish piece of split limestone in a site in Croatia that suggests Neanderthals 130,000 years ago collected the rock that stands out among all other items in the cave.

"If we were walking and picked up this rock, we would have taken it home," said David Frayer, a professor emeritus of anthropology who was part of the study. "It is an interesting rock."

An international team of researches that includes David Frayer, emeritus professor of anthropology, discovered a limestone rock that stood out among other items at the Krapina site in Croatia, where researchers have found Neanderthal fossils dated 130,000 years ago. The researchers believe the rock is evidence that Neanderthals were able to collect items and assign symbolic significance to them, a trait more commonly associated with Homo sapiens. Their findings appeared recently in the French journal Comptes Rendus Palevol. 
Credit: David Frayer.

The finding is important, he said, because it adds to other recent evidence that Neanderthals were capable — on their own — of incorporating symbolic objects into their culture. The rock was collected more than 100 years ago from the Krapina Neanderthal site, which has items preserved in the Croatian Natural History Museum in Zagreb, where in recent years the research team has re-examined them.

The group's findings on the collected rock at Krapina were published recently in the French journal Comptes Rendus Palevol. Davorka Radovčić, curator at the Croatian Natural History Museum, was the study's lead author, and Frayer is the corresponding author.

Credit: David Frayer.

The same research group in a widely recognized 2015 study published a PLOS ONE article about a set of eagle talons from the same Neanderthal site that included cut marks and were fashioned into a piece of jewelry.

"People have often defined Neanderthals as being devoid of any kind of aesthetic feelings, and yet we know that at this site they collected eagle talons and they collected this rock. At other sites, researchers have found they collected shells and used pigments on shells," Frayer said. "There's a little bit of evidence out there to suggest that they weren't the big, dumb creatures that everybody thinks they were."

Similar to the Neanderthal jewelry discovery at Krapina, Frayer credits Radovčić's keen eye in examining all items found at that the site, originally excavated between 1899-1905 and found to contain Neanderthal bones.

Credit: David Frayer.

The cave at the Krapina site was sandstone, so the split limestone rock stuck out as not deriving from the cave, Frayer said. None of the more than 1,000 lithic items collected from Krapina resemble the rock, but the original archaeologists apparently did nothing more with the rock other than to collect it.

Frayer said the limestone rock — which is roughly 5 inches long, 4 inches high and about a half-inch thick — did not have any striking platforms or other areas of preparation on the rock's edge, so the research team assumed it was not broken apart.

"The fact that it wasn't modified, to us, it meant that it was brought there for a purpose other than being used as a tool," Frayer said.

There was a small triangular flake that fits with the rock, but the break appeared to be fresh and likely happened well after the specimen was deposited into the sediments of the Krapina site. Perhaps it occurred during transport or storage after the excavation around 1900, he said.

The look of the rock also caught the researchers' eye as many inclusions or black lines on it stood out from the brown limestone. Perhaps that is what made the Neanderthal want to collect it in the first place.

"It looked like it is important," Frayer said. "We went back through all the collected items to make sure there weren't other rocks like it. It just sat there for 100 years like most of the other stuff from the site. The original archaeologists had described stone tools but didn't pay any attention to this one."

They suspect a Neanderthal collected the rock from a site a few kilometers north of the Krapina site where there were known outcrops of biopelmicritic grey limestone. Either the Neanderthal found it there or the Krapinica stream transported it closer to the site.

The discovery of the rock collection is likely minor compared with other discoveries, such as more modern humans 25,000 years ago making cave paintings in France. However, Frayer said it added to a body of evidence that Neanderthals were capable assigning symbolic significance to objects and went to the effort of collecting them.

The discovery could also provide more clues as to how modern humans developed these traits, he said.

"It adds to the number of other recent studies about Neanderthals doing things that are thought to be unique to modern Homo sapiens," Frayer said. "We contend they had a curiosity and symbolic-like capacities typical of modern humans."

The study's other co-au of Geology and Paleontology with the Croatian Natural History Museum.

Authors are Ankica Oros Sršen, of the Institute for Quaternary Paleontology and Geology at the Croatian Academy of Science and Arts, and Dražen Japundžić and Jakov Radovčić, both of the Department

Contacts and sources:
George Diepenbrock
University of Kansas

A Tale of Two Pulsars' Tails: Plumes Offer Geometry Lessons to Astronomers

Like cosmic lighthouses sweeping the universe with bursts of energy, pulsars have fascinated and baffled astronomers since they were first discovered 50 years ago. In two studies, international teams of astronomers suggest that recent images from NASA's Chandra X-ray Observatory of two pulsars -- Geminga and B0355+54 -- may help shine a light on the distinctive emission signatures of pulsars, as well as their often perplexing geometry.

Pulsars are a type of neutron star that are born in supernova explosions when massive stars collapse. Discovered initially by lighthouse-like beams of radio emission, more recent research has found that energetic pulsars also produce beams of high energy gamma rays.

Images captured by NASA's Chandra X-ray Observatory (top) with artist representations (below) that provided a better look at pulsars and their associated wind nebulae. Germinga, left, is approximately 800 light years from earth. Germinga's tail can stretch more than half a light year longer than 1,000 times the distance between the Sun and Pluto. BO355+54, right, is approximately 3,300 light years from Earth. The narrow, double tail extends almost five light years away from the star. 

Credit: Top Left X-ray: NASA/CXC/PSU/B.Posselt et al; Infrared (BACKGROUND): NASA/JPL-Caltech Top Right X-ray: NASA/CXC/GWU/N.Klinger et al; Infrared (BACKGROUND): NASA/JPL-Caltech Bottom illustrations by Nahks Tr'Ehnl

Interestingly, the beams rarely match up, said Bettina Posselt, senior research associate in astronomy and astrophysics, Penn State. The shapes of observed radio and gamma-ray pulses are often quite different and some of the objects show only one type of pulse or the other. These differences have generated debate about the pulsar model.

"It's not fully understood why there are variations between different pulsars," said Posselt. "One of the main ideas here is that pulse differences have a lot to do with geometry -- and it also depends on how the pulsar's spin and magnetic axes are oriented with respect to line of sight whether you see certain pulsars or not, as well as how you see them."

Chandra's images are giving the astronomers a closer than ever look at the distinctive geometry of the charged particle winds radiating in X-ray and other wavelengths from the objects, according to Posselt. Pulsars rhythmically rotate as they rocket through space at speeds reaching hundreds of kilometers a second. Pulsar wind nebulae (PWN) are produced when the energetic particles streaming from pulsars shoot along the stars' magnetic fields, form tori -- donut-shaped rings -- around the pulsar's equatorial plane, and jet along the spin axis, often sweeping back into long tails as the pulsars' quickly cut through the interstellar medium.

"This is one of the nicest results of our larger study of pulsar wind nebulae," said Roger W. Romani, professor of physics at Stanford University and principal investigator of the Chandra PWN project. "By making the 3-D structure of these winds visible, we have shown how one can trace back to the plasma injected by the pulsar at the center. Chandra's fantastic X-ray acuity was essential for this study, so we are happy that it was possible to get the deep exposures that made these faint structures visible."

A spectacular PWN is seen around the Geminga pulsar. Geminga -- one of the closest pulsars at only 800 light years away from Earth -- has three unusual tails, said Posselt. The streams of particles spewing out of the alleged poles of Geminga -- or lateral tails -- stretch out for more than half a light year, longer than 1,000 times the distance between the Sun and Pluto. Another shorter tail also emanates from the pulsar.

The astronomers said that a much different PWN picture is seen in the X-ray image of another pulsar called B0355+54, which is about 3,300 light years away from Earth. The tail of this pulsar has a cap of emission, followed by a narrow double tail that extends almost five light years away from the star.

While Geminga shows pulses in the gamma ray spectrum, but is radio quiet, B0355+54 is one of the brightest radio pulsars, but fails to show gamma rays.

"The tails seem to tell us why that is," said Posselt, adding that the pulsars' spin axis and magnetic axis orientations influence what emissions are seen on Earth.

According to Posselt, Geminga may have magnetic poles quite close to the top and bottom of the object, and nearly aligned spin poles, much like Earth. One of the magnetic poles of B0355+54 could directly face the Earth. Because the radio emission occurs near the site of the magnetic poles, the radio waves may point along the direction of the jets, she said. Gamma-ray emission, on the other hand, is produced at higher altitudes in a larger region, allowing the respective pulses to sweep larger areas of the sky.

An artist's representation of what the three unusual tails of the pulsar Geminga may look like close up. NASA's Chandra X-ray Observatory is giving astronomers a better look at pulsars and their associated pulsar wind nebulae, enabling new constraints on the geometry of pulsars and why they look the way they do from Earth.
Credit: Nahks Tr'Ehnl

"For Geminga, we view the bright gamma ray pulses and the edge of the pulsar wind nebula torus, but the radio beams near the jets point off to the sides and remain unseen," Posselt said.

The strongly bent lateral tails offer the astronomers clues to the geometry of the pulsar, which could be compared to either jet contrails soaring into space, or to a bow shock similar to the shockwave created by a bullet as it is shot through the air.

Oleg Kargaltsev, assistant professor of physics, George Washington University, who worked on the study on B0355+54, said that the orientation of B0355+54 plays a role in how astronomers see the pulsar, as well. The study is available online in arXiv.

"For B0355+54, a jet points nearly at us so we detect the bright radio pulses while most of the gamma-ray emission is directed in the plane of the sky and misses the Earth," said Kargaltsev. "This implies that the pulsar's spin axis direction is close to our line-of-sight direction and that the pulsar is moving nearly perpendicularly to its spin axis."

Noel Klingler, a graduate research assistant in physics, George Washington University, and lead author of the B0355+54 paper, added that the angles between the three vectors -- the spin axis, the line-of-sight, and the velocity -- are different for different pulsars, thus affecting the appearances of their nebulae.

"In particular, it may be tricky to detect a PWN from a pulsar moving close to the line-of-sight and having a small angle between the spin axis and our line-of-sight," said Klingler.

In the bow-shock interpretation of the Geminga X-ray data, Geminga's two long tails and their unusual spectrum may suggest that the particles are accelerated to nearly the speed of light through a process called Fermi acceleration. The Fermi acceleration takes place at the intersection of a pulsar wind and the interstellar material, according to the researchers, who report their findings on Geminga in the current issue of Astrophysical Journal.

Although different interpretations remain on the table for Geminga's geometry, Posselt said that Chandra's images of the pulsar are helping astrophysicists use pulsars as particle physics laboratories. Studying the objects gives astrophysicists a chance to investigate particle physics in conditions that would be impossible to replicate in a particle accelerator on earth.

"In both scenarios, Geminga provides exciting new constraints on the acceleration physics in pulsar wind nebulae and their interaction with the surrounding interstellar matter," she said.

Contacts and sources:
Matt Swayne
Penn State

Flexible Ferroelectrics Bring Two Material Worlds Together

Deafening silence. Jumbo shrimp. Same difference.

Until recently, “flexible ferroelectrics” could have been thought of as the same type of oxymoronic phrase. However, thanks to a new discovery by the U.S. Department of Energy’s (DOE) Argonne National Laboratory in collaboration with researchers at Northwestern University, scientists have pioneered a new class of materials with advanced functionalities that moves the idea from the realm of irony into reality.

Ferroelectrics are a useful type of material that is found in capacitors that are used in sensors, as well as computer memory and RFID cards. Their special properties originate from the fact that they contain charged regions polarized in a specific orientation, which can be controlled with an external electric field. But they’ve also had a big drawback as engineers try to use them in new inventions.

A scanning electron microscopy image of flexible haloimidazole crystals, which were found to show both ferroelectric and piezoelectric properties

Credit: Seungbum Hong/Argonne National Laboratory

A scanning electron microscopy image of flexible haloimidazole crystals, which were found to show both ferroelectric and piezoelectric properties.
“Ferroelectric materials are known for being quite brittle, and so it has always been a big challenge to make them mechanically flexible,” said Argonne nanoscientist Seungbum Hong, who helped to lead the research. “Because ferroelectricity and this kind of flexibility are relatively rare properties to see on their own, to have both ferroelectricity and flexibility in this new material is basically unprecedented.”

Previous generations of ferroelectric materials were primarily ceramic, Hong said, which made them fairly brittle. In the new material, the crystal planes at the atomic level tend to slip past one another, adding to the material’s ductility.

One advantage of flexible ferroelectrics comes from the fact that all ferroelectric materials are also piezoelectric, which means they can convert an applied mechanical force into an electrical signal, or vice versa; for example, when you flick a lighter to generate a spark. Having more flexible ferroelectrics could enable a greater response from a smaller input.

With flexible ferroelectrics, scientists and engineers may have the opportunity to adapt these materials for a host of new and improved uses, including precision actuators for atomic force microscopy, ultrasonic imaging sensors and emitters for medical applications and even sensors for some automotive applications.

For data storage, the impact may be even greater. “There’s a very large information density potential with ferroelectric storage,” Hong said. “This could make a big difference as we think about future generations of the data cloud.”

An article based on the research, “Flexible ferroelectric organic crystals,” was published online in Nature Communications in October. One of the lead Northwestern authors of the study, Sir Fraser Stoddart, received the 2016 Nobel Prize in Chemistry for his work on molecular machines.

Contacts and sources:
Argonne National Laboratory

Newly Discovered Mechanism in Cells Can Regulate The Immune System

Special proteins are important for the function of cells and play an important role in processes and effectiveness of the immune system. Researchers from the Niels Bohr Institute have observed how concentrations that vary over time can affect cells and they have demonstrated the existence of a mechanism, which is a new way of controlling the production of proteins that are related to processes which are important in order to avoid serious diseases, including cancer and Alzheimer’s. The results have been published in the scientific journal, Cell Systems.

As the signal amplitude of the TNF protein increases, several different synchronization modes can arise. The figure shows how different synchronizations of the TNF protein outside the cell, and the NF-kB protein inside the cell appears as a function of the oscillations in the TNF. 
Credit: M. Høgh Jensen og M. Heltberg, NBI

The formation of certain proteins is crucial to how living organisms function. It has long been established that many of the most important proteins vary in concentration in certain time intervals. It is said that the concentration ‘swings’, but why is not properly understood. Now researchers from the Niels Bohr Institute have studied the special protein, NF-kB, which is formed inside the cells and it is extremely important for controlling disease. The protein regulates about 200 genes that are of importance for functional disorders and the immune system and it is therefore essential for the body’s ability to fight diseases like cancer, Alzheimer’s and diabetes.

Mathias Heltberg, PhD student and Mogens Høgh Jensen, professor in Biocomplexity at the Niels Bohr Institute, University of Copenhagen have demonstrated the existence of a mechanism to control the production of proteins that are essential in order to avoid serious diseases, including cancer and Alzheimer’s.

Photo: Ola Jakup Joensen

Fluctuations synchronised controlling diseases. The protein, TNF (orange) is applied outside the cell in concentrations that varies in 

In collaboration with research groups in Zurich and Chicago, researchers from the Niels Bohr Institute at the University of Copenhagen have studied what happens inside the individual cells when they are influenced from the outside by the protein, TNF, a so-called signalling protein that tells cells which proteins should be produced for the body to function as it should.

The special protein, NF-kB (blue), which is created inside the cells, is very important in the process of time like a wave. The TNF protein affects the creation of the NF-kB protein inside the cell, and the scientists measured similar fluctuations in the NF-kB concentration inside the cell as the fluctuations in TNF outside the cell. The two fluctuations became coupled, and could oscillate in multiple different, yet still synchronized ways.
Credit: M. Høgh Jensen og M. Heltberg, NBI

“In the experiment, TNF is added to the protein from the outside in such a way that the concentration varies over time like a wave. In part because there are indications that it happens this way in nature and partly because we can then measure how the TNF protein affects the formation of the NF-kB proteins in the cell,” explains Mogens Høgh Jensen, professor in Biocomplexity at the Niels Bohr Institute at the University of Copenhagen.

And the researchers detected a clear connection.

“We measured the same oscillations in the formation of the NF-kB protein inside the cell as well as the oscillation with the addition of the TNF protein outside the cell. The two oscillations were synchronised in their pendulum swings – just like the Dutch mathematician and physicist, Huygens proved 350 years ago, that two clocks placed in adjoining rooms synchronised the swing of their pendulums and fluctuated in sync. In the same way, the oscillations outside and inside of the cell affected each other and they simply became linked together and swung in sync. Thus you can control the production of important proteins using the mechanisms of physics,” explains Mogens Høgh Jensen.

Control of the cell’s genes

In the experiments, they also tried to confuse the cells by bringing them into different modes of oscillation.

“We discovered that if large enough oscillations are made in the TNF protein, you could get different oscillation modes of the NF-kB protein inside the cell, so that the synchronisation hopped between oscillations in single tempo and double tempo in the dynamic switching between the two modes. Of course there is still a lot we do not know, but it can provide a new opportunity to control what proteins are formed. This could therefore be important for future research and the fight against diseases,” explains Mathias Heltberg, PhD student in Biocomplexity at the Niels Bohr Institute, University of Copenhagen.

Based on these oscillation modes, they could predict how the cell could align the production of a variety of proteins and could also control the meaning of the coincidences that are always present in a very simple way.

Mogens Høgh Jensen and Mathias Heltberg point out that what they have found is that this mechanism potentially can be used to control the cell’s genetic response. This could have an enormous impact on how you fight some of the most challenging diseases and how future medicine can be developed to stimulate the immune system in the best way.  

Contacts and sources:
Mogens Høgh Jensen, Professor in Biocomplexity at the Niels Bohr Institute, University of Copenhagen,

Mathias Heltberg, PhD student in Biocomplexity at the Niels Bohr Institute, University of Copenhagen

Common Crop Chemical Leaves Bees Susceptible to Deadly Viruses

A chemical that is thought to be safe and is, therefore, widely used on crops -- such as almonds, wine grapes and tree fruits -- to boost the performance of pesticides, makes honey bee larvae significantly more susceptible to a deadly virus, according to researchers at Penn State and the U.S. Department of Agriculture.

"In the lab, we found that the commonly used organosilicone adjuvant, Sylgard 309, negatively impacts the health of honey bee larvae by increasing their susceptibility to a common bee pathogen, the Black Queen Cell Virus," said Julia Fine, graduate student in entomology, Penn State. "These results mirror the symptoms observed in hives following almond pollination, when bees are exposed to organosilicone adjuvant residues in pollen, and viral pathogen prevalence is known to increase. In recent years, beekeepers have reported missing, dead and dying brood in their hives following almond pollination, and exposure to agrochemicals, like adjuvants, applied during bloom, has been suggested as a cause."

This is a healthy bee larva developing seen on day six.

Credit: Julia Fine/Penn State

According to Chris Mullin, professor of entomology, Penn State, adjuvants in general greatly improve the efficacy of pesticides by enhancing their toxicities.

"Organosilicone adjuvants are the most potent adjuvants available to growers," he said. "Based on the California Department of Pesticide Regulation data for agrochemical applications to almonds, there has been increasing use of organosilicone adjuvants during crop blooming periods, when two-thirds of the U.S. honey bee colonies are present." Fine noted that the U.S. Environmental Protection Agency classifies organosilicone adjuvants as biologically inert, meaning they do not cause a reaction in living things.

"As a result," she said, "there are no federally regulated restrictions on their use."

To conduct their study, the researchers reared honey bee larvae under controlled conditions in the laboratory. During the initial stages of larval development, they exposed the larvae to a low chronic dose of Sylgard 309 in their diets. They also exposed some of the larvae to viral pathogens in their diets on the first day of the experiment.

"We found that bees exposed to the organosilicone adjuvant had higher levels of Black Queen Cell Virus," said Fine. "Not only that, when they were exposed to the virus and the organosilicone adjuvant simultaneously, the effect on their mortality was synergistic rather than additive, meaning that the mortality was higher from the simultaneous application of adjuvant and virus than from exposure to either the organosilicone adjuvant or the viral pathogen alone, even if those two mortalities were added together," said Fine. "This suggests that the adjuvant is enhancing the damaging effects of the virus."

This is a new be larva developing.
Credit: Julia Fine/Penn State

The researchers also found that a particular gene involved in immunity -- called 18-wheeler -- had reduced expression in bees treated with the adjuvant and the virus, compared to bees in the control groups.

"Taken together, these findings suggest that exposure to organosilicone adjuvants negatively influences immunity in honey bee larvae, resulting in enhanced pathogenicity and mortality," said Fine.

The results appear today (Jan. 16) in Scientific Reports.

Mullin noted that the team's results suggest that recent honey bee declines in the United States may, in part, be due to the increased use of organosilicone adjuvants.

This is a dead bee pupa.
Credit: Julia Fine/Penn State

"Billions of pounds of formulation and tank adjuvants, including organosilicone adjuvants, are released into U.S. environments each year, making them an important component of the chemical landscape to which bees are exposed," he said. "We now know that at least Sylgard 309, when combined at a field-relevant concentration with Black Queen Cell Virus, causes synergistic mortality in honey bee larvae."

Contacts and sources:
A'ndrea Elyse Messer
Penn State

Killer Bug Could Deliver Medicines

A bacterium that causes pneumonia is being redesigned to act as a 'cell doctor' that detects and treats disease from inside the human body.

The idea of using bugs as tiny drug couriers is not new: scientists have been engineering viruses to deliver medicines and fix genetic defects for some time.

However, the potential of viruses is limited because they have a small number of genes and because they do not have an active metabolism of their own and cannot respond to the environment or the host. This limits the scope for their engineering for certain medical purposes.

‘Viruses can only carry a limited amount of information,’ said Professor Luis Serrano at the Centre for Genomic Regulation in Barcelona, Spain. ‘They have genes but, unlike bacteria, they do not have a metabolism so they cannot respond to changes in a human cell.’
Credit: © kasto - fotolia

Using bacteria instead of viruses to deliver treatments to specific parts of the body would provide greater scope for fighting disease because they have more genes to tweak.

However, bacteria are also significantly more complex to work with. For a start, they typically have cell walls – making it difficult for them to communicate with target cells – and they often draw a strong immune response when implanted into humans.

Now, scientists believe they may have found a suitable candidate that has more genes than a virus but is capable of getting into cells to carry out medical missions – and it’s one that we’ve previously associated with disease.

Mycoplasma pneumoniae can cause bacterial pneumonia in humans, but also ticks many of the boxes required to become a cell doctor. ‘It has no cell wall, it does not cause major inflammation and it can be grown in the lab,’ explained Prof. Serrano, who studied the bug as part of the CELLDOCTOR project, funded by the EU's European Research Council (ERC).

M. pneumoniae is also a very small bacterium. It is roughly the size of a mitochondrion – the subcellular powerhouse that provides our cells with energy.

Because it is so small and can enter cells without triggering a major immune reaction, Prof. Serrano sees the bug’s potential as a medical tool.

‘We want to engineer a vehicle that can get into the human organism, detect anomalies and repair them,’ he said. ‘It could live inside human cells like a parasite capable of improving health.’

Once inside the target cell, the bacterium would blend in with the other structures already there. But unlike the cell’s other subcellular furniture, the engineered M. pneumoniae bacterium would produce and secrete drugs that a patient needs, or proteins capable of correcting a genetic disease.

It would not cause disease itself because the researchers have genetically engineered the pneumoniae bacterium to ensure that it is not infectious.

Through the CELLDOCTOR project, Prof. Serrano focused on understanding what makes the bacterium tick before exploring its capacity for delivering drugs, vaccines and genes.

By understanding its genetics and biochemistry, the Barcelona-based researchers developed a deeper understanding of the bug – so that they could redesign a simple organism that would act like a living pill.

Thanks to additional ERC funding, Prof. Serrano was able to take this work one step further and look at specific uses of M. pneumoniae for treating lung and genital tract diseases in a project called MICO PLUNG.

‘Our initial work was pointing towards medical applications for M. pneumoniae and this… project was a chance to direct our efforts towards more clinically applied research,’ he explained.
Respiratory disorders

The bacterium is known to live in lung tissue, so researchers are working on how genetically engineered versions of the bug could deliver therapeutic proteins that could fight against infectious respiratory disorders.

The team also see potential for bacteria to be used as vaccines, deliberately training the immune system to fight unwelcome viruses and bacteria.

Research in this area may change the way we think about bacteria such as M. pneumoniae by turning an old foe into a valuable ally.

Contacts and sourcesL
'EC Research and Innovation

(The story was first published in Horizon Magazine)

Male Pipefish Pregnancy, It's Complicated

In the upside-down world of the pipefish, sexual selection appears to work in reverse, with flashy females battling for males who bear the pregnancy and carry their young to term in their brood pouch. But new research shows even more factors appear to play a role in determining mating success.

For most species, males compete for access to females – think, a peacock's tail or a buck's antlers. But in some species, the sex roles are reversed and males carry the brood, as in the case of pipefish and other members of the Syngnathus family like the seahorse. In these cases, females must compete for access to available mates, and indeed, researchers have found secondary sex traits, such as brightly colored ornamentation, evolving in female pipefish instead of males. Previous studies have also found that large female pipefish, which are able to transfer more eggs to the male's pouch, are more attractive to the males.

A variety of factors determine mating success in the sex-role reversed pipefish, according to new research.
Credit: The National Institute for Mathematical and Biological Synthesis

But, in new study published in the journal Behavioral Ecology and Sociobiology, researchers found that the size of male pipefish matters too. The paper can be read here.

A team of researchers in the United States and Sweden sampled a population of broadnosed pipefish (Syngnathus typhle) at the beginning of the breeding season in shallow eelgrass beds in Kyllaj, Gotland, Sweden. They found that larger males bred first and their offspring had a better chance of surviving.

Large males with larger embryos invested more energy per embryo than smaller males, produced more newborn offspring, and their offspring survived predation better as compared to the offspring from small males.

The study suggests that larger males have a clear reproductive advantage in the wild over the smaller males. And timing is important too – if they breed earlier, they increase their chances of being able to have more pregnancies before the end of the breeding season.

"From a research standpoint, pipefish are interesting because of the unique opportunity they provide to study sexual selection in reverse, which can tell us a lot about how variation works in mating and reproductive success," said lead author Sarah Flanagan, a postdoctoral fellow at the National Institute for Mathematical and Biological Synthesis.

"This study shows that there are many factors at play in this system, more than perhaps we ever realized, but it's that variation in traits and fitness which allows for sexual selection to work," Flanagan said.

At NIMBioS, Flanagan is extending the research by exploring the role that genetics plays in complex systems in species like pipefish.

Contacts and sources:
Catherine Crawley
The National Institute for Mathematical and Biological Synthesis

Citation: Flanagan SP, Rosenqvist G, Jones AG. Mate quality and the temporal dynamics of breeding in a sex-role-reversed pipefish, S. typhle. Behavioral Ecology and Sociobiology. [Online]

Global Warming Disrupts Fish Stocks

The global catch of fish would largely benefit from achieving the 1.5°C global warming target. This is the conclusion of the study recently published by climate researchers from ETH Zurich and the University of British Columbia in the journal Science .

If sea temperatures rise, how do fish survive? Tropical fish will need to migrate to cooler waters.

(photo: stock_colors / iStock)

In the last twelve months, a large number of countries signed the Paris Agreement with the aim to limit global warming to no more than 1.5 degrees Celsius above pre-industrial levels. However, it is currently unclear how the world will achieve this ambitious climate target. Demonstrating the benefits to human society of meeting – or even undercutting – this goal will hopefully encourage countries and private sectors to make strong commitments to achieve it.

Scientists at ETH Zurich and the University of British Columbia have therefore translated the Paris climate target to the global fisheries, which are supporting billions of people for food, livelihood and culture. In doing so, they highlight how this important sector would benefit from meeting this goal. Their study has just been published in the journal “Science”.
A rise of less than 2 degrees can benefit fisheries

According to simulations from the researcher’s computer models, the fishing industry would strongly benefit if the Paris Agreement global warming target of 1.5°C would be met. The maximum catch potential of fish would increase by three percent for every degree Celsius decrease in surface temperature. The global fish catch is around 88 million tonnes in 2014 as reported by the Food and Agricultural Organization (FAO).

The researchers also found that some oceans will benefit much more from achieving the global warming target. Fishermen in the tropical Pacific Ocean would see their catch shrink by 12 percent if the 1.5 degree rise in temperature is met, while a 3.5 degree increase would lead to a reduction of 47 percent. The benefits for vulnerable tropical countries is therefore a strong reason why 1.5°C should be met. “People living in these regions rely heavily on fish as their primary protein source from animals,” stresses Thomas Frölicher, co-author of the study, and senior scientist at the ETH Institute of Biogeochemistry and Pollutant Dynamics (IBP).

In a warming climate, fishes shift to cooler waters. 
Graphics: Lindsay Lafreniere

By contrast, Arctic fishing boats could see their catch increase by a fifth for every degree Celsius rise in surface temperature. The warming will have a positive effect on fisheries in the Arctic region, because it reduces the amount of sea ice and allows more light and heat to penetrate the ocean. This promotes the growth of phytoplankton, which in turn boosts fish stocks. In addition, fish stocks in the Arctic region will increase due to the invasion of species from warmer low latitude regions. If the 1.5°C target agreed in Paris could be met, Arctic fishermen would see their catch increase by about 30 percent. A rise in surface temperature of 3.5°C would boost their catch by 55 percent. In extreme cases, the local catch could even quadruple.

Fish stocks in the high northern latitudes will not necessarily always benefit from the ocean’s increased warming and productivity. A tipping point will eventually be reached after which the increase in temperature has negative consequences for Arctic fisheries. For example, fish stocks in the North Sea will start to decrease again as soon as the average temperature rise exceeds about 3.5 degrees. This is because high water temperatures result in more stable stratification of the ocean, which in turn inhibits the growth of phytoplankton.
Direct connection between emissions and catch

“The correlation between the average global temperature and the cumulative man-made carbon-dioxide emissions into the atmosphere is linear, just like the connection between global fishing yields and temperature," explains Frölicher. This makes it possible to directly calculate the impact of one tonne of CO2 emissions on the global fishing catch.

At present, the resolution of the climate models is to some extent not high enough to make robust predictions for individual coastal regions. Frölicher and his colleagues are therefore working on a follow-up study that will use climate models with much higher resolution.

The ETH scientist is part of a group of fish experts, called the Nippon Foundation-Nereus Program, which is co-led by lead author of the paper Professor William Cheung at the University of British Columbia. The Canadian researchers have developed a computer programme that enables them to model the population of 900 different species of fish. This fish model includes environmental conditions for the fish, such as water temperature, and the level of nutrients and oxygen in the water. The team has coupled these potential populations with existing climate models simulations in order to determine the living conditions of fish under different climate scenarios. “The models highlight where fishes might migrate to in the future,” says Frölicher.
Out of the comfort zone

Depending on the future climate change scenario, tropical fish currently living in waters between 27 and 29 degrees Celsius will be faced with water that is one to 2 degrees higher. However, many species will be unable to adapt to these conditions, also because warm water contains less oxygen. As a result, the fishes have to search for a new habitat. “Once the temperature reaches a certain threshold, these fish will be forced to migrate to cooler waters in order to survive,” warns Frölicher.

Contacts and sources:
Peter Rüegg 
ETH Zurich

Citation: Cheung WWL, Reygondeau G, Frölicher TL. Large benefits to marine fisheries of meeting the 1.5°C global warming target. Science, Advanced Online Publication, 22 Dec 2016. doi:10.1126/science.aag2331

Malaria Infection Depends on Number of Parasites, Not Number of Mosquito Bites

For the first time, researchers have shown that the number of parasites each mosquito carries influences the chance of successful malaria infection.

The finding has implications for vaccine development and studies into how the disease spreads in the field.

The findings, from scientists at Imperial College London, may also explain why the only registered malaria vaccine, RTS,S, has had only partial efficacy in recent trials. Malaria is spread when mosquitoes bite humans and release microscopic parasites, which live in the salivary glands of the mosquitoes, into the person’s bloodstream.

The parasites then travel to the liver, where they mature and multiply for 8-30 days before spreading throughout the bloodstream and causing the symptoms of malaria.

Credit: Imperial College London

Not every infectious mosquito bite will result in malaria. To determine the intensity of malaria transmission, researchers and international organisations like the World Health Organisation currently rely on a measure called the entomological inoculation rate (EIR): the average number of potentially infectious mosquito bites per person per year.

However, this does not take into account how infectious each of those bites may be – each bite is considered equally infectious. Previous studies using needle-injected parasites have suggested this may not be the case, but there have been no comprehensive studies using biting mosquitoes, which more accurately reflect real-world scenarios.

Now, in a study funded by the PATH Malaria Vaccine Initiative and the Medical Research Council, published in the journal PLoS Pathogens, researchers have determined that the number of parasites each individual mosquito carries influences whether a person will develop malaria. Some mosquitoes can be ‘hyperinfected’, making them particularly likely to pass on the disease.
Significant implications

In studies in mice, the researchers determined that the more parasites present in a mosquito’s salivary glands, the more likely it was to be infectious, and also the faster any infection would develop.

Study co-author Dr Andrew Blagborough, from the Department of Life Sciences at Imperial, said: “These findings could have significant implications for public health. We have shown that the concept of relying on the number of bites alone to predict malarial burden is flawed, and has probably hampered the successful use of control measures and the development of effective vaccines.

“It is surprising that the relationship between parasite density and infectiousness has not been properly investigated before, but the studies are quite complex to carry out.”

The team set up repeated cycles of infection, so that groups of infected mosquitoes containing variable numbers of parasites repeatedly bit sedated mice, transmitting malaria to them under a range of transmission settings.

This allowed them to track how many individual parasites different mosquitoes harboured, how many mice were infected as a result of exposure to them, and how long it took the mice to develop malaria.
Vaccine development

By conducting further studies with mice and human volunteers, the team were also able to explain why the malaria vaccine RTS,S is effective only around 50 percent of the time, and why any protection rapidly drops off after three years.

The vaccine was less effective when mice or humans were bitten by mosquitoes carrying a greater number of parasites. The researchers think this is because the vaccine can only kill a certain proportion of the parasites, and is overwhelmed when the parasite population is too large.

All malaria-affected regions will have a mix of mosquitoes carrying different parasite amounts. Dr Blagborough said: “The majority of mosquitoes in the wild are either uninfected or infected at quite low levels, but some individual mosquitoes are regularly very highly infected.

“As the levels of malaria drop in an area due to the successful use of interventions, the number of these hyperinfected mosquitoes is expected to drop – but they’re not totally prevented unless the intervention is very powerful.”

Study co-author Dr Thomas Churcher, from the MRC Centre for Outbreak Analysis and Modelling at Imperial, said: “Vaccine development has come a long way, and this new insight should help future vaccine studies to be tested more rigorously.

“However, in the end, it is unlikely that one magic bullet will eradicate malaria, and we should continue to seek and apply combinations of strategies for reducing the burden of this disease.”

Dr Morvern Roberts, programme manager for global infections at the Medical Research Council who funded the research, said: “Researchers have long wondered whether the more malaria parasites in a mosquito’s mouthparts, the more likely they are to infect a host with the disease. No one has been able to demonstrate this until now but the authors of this paper have shown that this is the case in both mouse models and in humans.

“As they suggest, this knowledge is extremely important to take into account when trying to develop vaccines for malaria and other vector-borne diseases.”

Contacts and sources:
Hayley Dunning
Imperial College London

Probability of Transmission of Malaria from Mosquito to Human is Regulated by Mosquito Parasite Density in Naïve and Vaccinated Hosts” by Thomas S. Churcher et al, is published in PLoS Pathogens

Antidepressants – a Death Trap for Fish

While antidepressants may keep humans happy they are detrimental to our fish population, according to new international research led by Monash University biologists.

The research published in Environment Pollution and led by PhD student Jake Martin from the Monash Faculty of Science, has found that Fluoxetine – a common form of antidepressants – adversely affects the behaviour of fish and impedes their responses to potential predators.

Credit; Monash University

The research is significant because it has found that changes in the behaviour of fish occurs at very low exposure concentrations of Fluoxetine that are often detected in our waterways.

“For example we found that Mosquitofish exposed to Fluoxetine are more active and actually venture quicker into the vicinity of dragonfly nymphs, which are a common aquatic predator of small fish,” said Mr Martin.

“And the escape response of the fish is also compromised,” he said.

Fluoxetine-exposed fish reduced their ‘freezing’ behaviour – a common strategy used by fish to avoid detection by a predator – following a simulated predator strike.

“Our research shows that such behavioural shifts can make Fluoxetine-exposed fish more vulnerable to being captured and eaten,” Mr Martin said.

The findings highlight the wider issue of environmental contamination by human and veterinary pharmaceuticals that end up in waterways because of ineffective removal through wastewater treatment processes.

“Pharmaceutical pollution is a serious environmental problem”, says Associate Professor Bob Wong, the senior author on the research paper.

“Hundreds of pharmaceutical products have been detected in the environment and their impacts on wildlife and ecosystems are still poorly understood”.

The article in Environment Pollution can be found here.

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