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Sunday, February 28, 2016

Frozen Canyons Found at Pluto’s North Pole

This ethereal scene captured by NASA’s New Horizons spacecraft tells yet another story of Pluto’s diversity of geological and compositional features—this time in an enhanced color image of the north polar area.

Credits: NASA/JHUAPL/SwRI

Long canyons run vertically across the polar area—part of the informally named Lowell Regio, named for Percival Lowell, who founded Lowell Observatory and initiated the search that led to Pluto’s discovery. The widest of the canyons (yellow in the image below) – is about 45 miles (75 kilometers) wide and runs close to the north pole. Roughly parallel subsidiary canyons to the east and west (in green) are approximately 6 miles (10 kilometers) wide. The degraded walls of these canyons appear to be much older than the more sharply defined canyon systems elsewhere on Pluto, perhaps because the polar canyons are older and made of weaker material. These canyons also appear to represent evidence for an ancient period of tectonics.

A shallow, winding valley (in blue) runs the entire length of the canyon floor. To the east of these canyons, another valley (pink) winds toward the bottom-right corner of the image. The nearby terrain, at bottom right, appears to have been blanketed by material that obscures small-scale topographic features, creating a ‘softened’ appearance for the landscape.



This image was obtained by New Horizons’ Ralph/Multispectral Visible Imaging Camera (MVIC). The image resolution is approximately 2,230 feet (680 meters) per pixel. The lower edge of the image measures about 750 miles (1,200 kilometers) long. It was obtained at a range of approximately 21,100 miles (33,900 kilometers) from Pluto, about 45 minutes before New Horizons’ closest approach on July 14, 2015.

Credits: NASA/JHUAPL/SwRI

Large, irregularly-shaped pits (in red), reach 45 miles (70 kilometers) across and 2.5 miles (4 kilometers) deep, scarring the region. These pits may indicate locations where subsurface ice has melted or sublimated from below, causing the ground to collapse.

The color and composition of this region – shown in enhanced color – also are unusual. High elevations show up in a distinctive yellow, not seen elsewhere on Pluto. The yellowish terrain fades to a uniform bluish gray at lower elevations and latitudes. New Horizons' infrared measurements show methane ice is abundant across Lowell Regio, and there is relatively little nitrogen ice. “One possibility is that the yellow terrains may correspond to older methane deposits that have been more processed by solar radiation than the bluer terrain,” said Will Grundy, New Horizons composition team lead from Lowell Observatory, Flagstaff, Arizona.

Contacts and sources:
Tricia Talbert
NASA

Title for ‘Earth’s First Animal’ Likely Goes to Simple Sea Creature

The first animal to appear on Earth was very likely the simple sea sponge.

New genetic analyses led by MIT researchers confirm that sea sponges are the source of a curious molecule found in rocks that are 640 million years old. These rocks significantly predate the Cambrian explosion — the period in which most animal groups took over the planet, 540 million years ago — suggesting that sea sponges may have been the first animals to inhabit the Earth.

Credit:  MIT

“We brought together paleontological and genetic evidence to make a pretty strong case that this really is a molecular fossil of sponges,” says David Gold, a postdoc in MIT’s Department of Earth, Atmospheric and Planetary Sciences (EAPS). “This is some of the oldest evidence for animal life.”

The results are published today in the Proceedings of the National Academy of Sciences. Gold is the lead author on the paper, along with senior author and EAPS Professor Roger Summons.

See how MIT researchers found that sea sponges are likely to be Earth's first animal

Video: Melanie Gonick/MIT

Ancient molecular clues

Paleontologists have unearthed an extraordinary number of fossils from the period starting around 540 million years ago. Based on the fossil record, some scientists have argued that contemporary animal groups essentially “exploded” onto Earth, very quickly morphing from single-celled organisms to complex multicellular animals in a relatively short geological time span. However, the fossils that are known from before the Cambrian explosion are peculiar in many respects, making it extremely difficult to determine which type of animal was the first to the evolutionary line.

Summons’ lab has been looking for the answer in molecular fossils — trace amounts of molecules that have survived in ancient rocks long after the rest of an animal has decayed away.

“There’s a feeling that animals should be much older than the Cambrian, because a lot of animals are showing up at the same time, but fossil evidence for animals before that has been contentious,” Gold says. “So people are interested in the idea that some of these biomarkers and chemicals, molecules left behind, might help resolve these debates.”

In particular, he and his colleagues have focused on 24-isopropylcholestane, or 24-ipc for short — a lipid molecule, or sterol, that is a modified version of cholesterol. In 1994, Summons was part of a team, led by Mark McCaffrey PhD ’90, that first found 24-ipc, in unusually high amounts, in Cambrian and slightly older rocks. They speculated that sponges or their ancestors might be the source.

In 2009, a team led by University of California at Riverside Professor Gordon Love, then a postdoc in Summons’ lab, did the first detailed study of rocks in Oman. The researchers confirmed the presence of 24-ipc in 640-million-year-old rock samples, potentially representing the oldest evidence for animal life. That work utilized high precision uranium-lead dating techniques developed by EAPS Professor Samuel Bowring.

“This research topic has a 20-plus-year history intimately connected to MIT scientists,” Summons notes. “Now, in 2016 David Gold has been able to apply his skills and the new tools of the genomic era, to add a further layer of evidence supporting the ‘sponge biomarker hypothesis.’”

Growing an evolutionary tree

It’s known that some modern sea sponges and certain types of algae produce 24-ipc today, but which organism was around to make the molecule 640 million years ago? To answer this question, Summons and Gold sought to first identify the gene responsible for making 24-ipc, then find the organisms that carry this gene, and finally trace when the gene evolved in those organisms.

The team looked through the genomes of about 30 different organisms, including plants, fungi, algae, and sea sponges, to see what kinds of sterols each organism produces and to identify the genes associated with those sterols.

“What we found was this really interesting pattern across most of eukaryotic life,” Gold says.

By comparing genomes, they identified a single gene, sterol methyltransferase, or SMT, responsible for producing certain kinds of sterols depending on the number of copies of the gene an organism carries. The researchers found that sea sponge and algae species that produce 24-ipc have an extra copy of SMT when compared with their close relatives.

The researchers compared the copies to determine how they were all related and when each copy of the gene first appeared. They then mapped the relationships onto an evolutionary tree and used evidence from the fossil record to determine when each SMT gene duplication occurred.

No matter how they manipulated the timing of the evolutionary tree, the researchers found that sea sponges evolved the extra copy of SMT much earlier than algae, and they did so around 640 million years ago — the same time period in which 24-ipc was found in rocks.

Their results provide strong evidence that sea sponges appeared on Earth 640 million years ago, much earlier than any other animal life form.

“This brings up all these new questions: What did these organisms look like? What was the environment like? And why is there this big gap in the fossil record?” Gold says. “This goes to show how much we still don’t know about early animal life, how many discoveries there are left, and how useful, when done properly, these molecular fossils can be to help fill in those gaps.”

This research is supported, in part, by the Agouron Institute and the NASA Astrobiology Institute.



Contacts and sources: 
Jennifer Chu
Massachusetts Institute of Technology

Ultrathin, Flexible Photovoltaic Cells as Light as a Soap Bubble

Imagine solar cells so thin, flexible, and lightweight that they could be placed on almost any material or surface, including your hat, shirt, or smartphone, or even on a sheet of paper or a helium balloon.

Researchers at the Massachusetts Institute of Technology (MIT) have now demonstrated just such a technology: the thinnest, lightest solar cells ever produced. Though it may take years to develop into a commercial product, the laboratory proof-of-concept shows a new approach to making solar cells that could help power the next generation of portable electronic devices.

The MIT team has achieved the thinnest and lightest complete solar cells ever made, they say. To demonstrate just how thin and lightweight the cells are, the researchers draped a working cell on top of a soap bubble, without popping the bubble.
Credit: Joel Jean and Anna Osherov

The new process is described in a paper by MIT professor Vladimir Bulovi, research scientist Annie Wang, and doctoral student Joel Jean, in the journal Organic Electronics.

Bulovi, MIT's associate dean for innovation and the Fariborz Maseeh (1990) Professor of Emerging Technology, says the key to the new approach is to make the solar cell, the substrate that supports it, and a protective overcoating to shield it from the environment, all in one process. The substrate is made in place and never needs to be handled, cleaned, or removed from the vacuum during fabrication, thus minimizing exposure to dust or other contaminants that could degrade the cell's performance.

"The innovative step is the realization that you can grow the substrate at the same time as you grow the device," Bulovi says.

In this initial proof-of-concept experiment, the team used a common flexible polymer called parylene as both the substrate and the overcoating, and an organic material called DBP as the primary light-absorbing layer. Parylene is a commercially available plastic coating used widely to protect implanted biomedical devices and printed circuit boards from environmental damage. The entire process takes place in a vacuum chamber at room temperature and without the use of any solvents, unlike conventional solar-cell manufacturing, which requires high temperatures and harsh chemicals. In this case, both the substrate and the solar cell are "grown" using established vapor deposition techniques.

One process, many materials

The team emphasizes that these particular choices of materials were just examples, and that it is the in-line substrate manufacturing process that is the key innovation. Different materials could be used for the substrate and encapsulation layers, and different types of thin-film solar cell materials, including quantum dots or perovskites, could be substituted for the organic layers used in initial tests.

“It could be so light that you don’t even know it’s there, on your shirt or on your notebook,” Vladimir Bulović says. “These cells could simply be an add-on to existing structures.”

Photo: Joel Jean and Anna Osherov

But already, the team has achieved the thinnest and lightest complete solar cells ever made, they say. To demonstrate just how thin and lightweight the cells are, the researchers draped a working cell on top of a soap bubble, without popping the bubble. The researchers acknowledge that this cell may be too thin to be practical -- "If you breathe too hard, you might blow it away," says Jean -- but parylene films of thicknesses of up to 80 microns can be deposited easily using commercial equipment, without losing the other benefits of in-line substrate formation.

A flexible parylene film, similar to kitchen cling-wrap but only one-tenth as thick, is first deposited on a sturdier carrier material - in this case, glass. Figuring out how to cleanly separate the thin material from the glass was a key challenge, explains Wang, who has spent many years working with parylene.

The researchers lift the entire parylene/solar cell/parylene stack off the carrier after the fabrication process is complete, using a frame made of flexible film. The final ultra-thin, flexible solar cells, including substrate and overcoating, are just one-fiftieth of the thickness of a human hair and one-thousandth of the thickness of equivalent cells on glass substrates -- about two micrometers thick -- yet they convert sunlight into electricity just as efficiently as their glass-based counterparts.

No miracles needed

"We put our carrier in a vacuum system, then we deposit everything else on top of it, and then peel the whole thing off," explains Wang. Bulovi says that like most new inventions, it all sounds very simple -- once it's been done. But actually developing the techniques to make the process work required years of effort.

While they used a glass carrier for their solar cells, Jean says "it could be something else. You could use almost any material," since the processing takes place under such benign conditions. The substrate and solar cell could be deposited directly on fabric or paper, for example.

While the solar cell in this demonstration device is not especially efficient, because of its low weight, its power-to-weight ratio is among the highest ever achieved. That's important for applications where weight is important, such as on spacecraft or on high-altitude helium balloons used for research. Whereas a typical silicon-based solar module, whose weight is dominated by a glass cover, may produce about 15 watts of power per kilogram of weight, the new cells have already demonstrated an output of 6 watts per gram -- about 400 times higher.

"It could be so light that you don't even know it's there, on your shirt or on your notebook," Bulovi says. "These cells could simply be an add-on to existing structures."

Still, this is early, laboratory-scale work, and developing it into a manufacturable product will take time, the team says. Yet while commercial success in the short term may be uncertain, this work could open up new applications for solar power in the long term. "We have a proof-of-concept that works," Bulovi says. The next question is, "How many miracles does it take to make it scalable? We think it's a lot of hard work ahead, but likely no miracles needed."

The work was supported by Eni S.p.A. via the Eni-MIT Solar Frontiers Center, and by the National Science Foundation.


Contacts and sources: 
Sarah McDonnell
Massachusetts Institute of Technology

NASA’s IBEX Observations Pin Down Interstellar Magnetic Field


Immediately after its 2008 launch, NASA's Interstellar Boundary Explorer, or IBEX, spotted a curiosity in a thin slice of space: More particles streamed in through a long, skinny swath in the sky than anywhere else. The origin of the so-called IBEX ribbon was unknown - but its very existence opened doors to observing what lies outside our solar system, the way drops of rain on a window tell you more about the weather outside.

Now, a new study uses IBEX data and simulations of the interstellar boundary - which lies at the very edge of the giant magnetic bubble surrounding our solar system called the heliosphere - to better describe space in our galactic neighborhood.

Artist concept: Far beyond the orbit of Neptune, the solar wind and the interstellar medium interact to create a region known as the inner heliosheath, bounded on the inside by the termination shock, and on the outside by the heliopause.

Credit: NASA/IBEX/Adler Planetarium

The paper, published Feb. 8, 2016, in Astrophysical Journal Letters, precisely determines the strength and direction of the magnetic field outside the heliosphere. Such information gives us a peek into the magnetic forces that dominate the galaxy beyond, teaching us more about our home in space.

The new paper is based on one particular theory of the origin of the IBEX ribbon, in which the particles streaming in from the ribbon are actually solar material reflected back at us after a long journey to the edges of the sun's magnetic boundaries. A giant bubble, known as the heliosphere, exists around the sun and is filled with what's called solar wind, the sun's constant outflow of ionized gas, known as plasma. When these particles reach the edges of the heliosphere, their motion becomes more complicated.

This simulation shows the origin of ribbon particles of different energies or speeds outside the heliopause (labeled HP). The IBEX ribbon particles interact with the interstellar magnetic field (labeled ISMF) and travel inwards toward Earth, collectively giving the impression of a ribbon spanning across the sky.

Credits: SwRI/Zirnstein

"The theory says that some solar wind protons are sent flying back towards the sun as neutral atoms after a complex series of charge exchanges, creating the IBEX ribbon," said Eric Zirnstein, a space scientist at the Southwest Research Institute in San Antonio, Texas, and lead author on the study. "Simulations and IBEX observations pinpoint this process - which takes anywhere from three to six years on average - as the most likely origin of the IBEX ribbon."

Outside the heliosphere lies the interstellar medium, with plasma that has different speed, density, and temperature than solar wind plasma, as well as neutral gases. These materials interact at the heliosphere's edge to create a region known as the inner heliosheath, bounded on the inside by the termination shock - which is more than twice as far from us as the orbit of Pluto - and on the outside by the heliopause, the boundary between the solar wind and the comparatively dense interstellar medium.

Some solar wind protons that flow out from the sun to this boundary region will gain an electron, making them neutral and allowing them to cross the heliopause. Once in the interstellar medium, they can lose that electron again, making them gyrate around the interstellar magnetic field. If those particles pick up another electron at the right place and time, they can be fired back into the heliosphere, travel all the way back toward Earth, and collide with IBEX's detector. The particles carry information about all that interaction with the interstellar magnetic field, and as they hit the detector they can give us unprecedented insight into the characteristics of that region of space.

"Only Voyager 1 has ever made direct observations of the interstellar magnetic field, and those are close to the heliopause, where it's distorted," said Zirnstein. "But this analysis provides a nice determination of its strength and direction farther out."

The IBEX ribbon is a relatively narrow strip of particles flying in towards the sun from outside the heliosphere. A new study corroborates the idea that particles from outside the heliosphere that form the IBEX ribbon actually originate at the sun – and reveals information about the distant interstellar magnetic field.
Credits: SwRI

The directions of different ribbon particles shooting back toward Earth are determined by the characteristics of the interstellar magnetic field. For instance, simulations show that the most energetic particles come from a different region of space than the least energetic particles, which gives clues as to how the interstellar magnetic field interacts with the heliosphere.

For the recent study, such observations were used to seed simulations of the ribbon's origin. Not only do these simulations correctly predict the locations of neutral ribbon particles at different energies, but the deduced interstellar magnetic field agrees with Voyager 1 measurements, the deflection of interstellar neutral gases, and observations of distant polarized starlight.

However, some early simulations of the interstellar magnetic field don't quite line up. Those pre-IBEX estimates were based largely on two data points - the distances at which Voyagers 1 and 2 crossed the termination shock.

"Voyager 1 crossed the termination shock at 94 astronomical units, or AU, from the sun, and Voyager 2 at 84 AU," said Zirnstein. One AU is equal to about 93 million miles, the average distance between Earth and the sun. "That difference of almost 930 million miles was mostly explained by a strong, very tilted interstellar magnetic field pushing on the heliosphere."

But that difference may be accounted for by considering a stronger influence from the solar cycle, which can lead to changes in the strength of the solar wind and thus change the distance to the termination shock in the directions of Voyager 1 and 2. The two Voyager spacecraft made their measurements almost three years apart, giving plenty of time for the variable solar wind to change the distance of the termination shock.

"Scientists in the field are developing more sophisticated models of the time-dependent solar wind," said Zirnstein.

The simulations generally jibe well with the Voyager data.

"The new findings can be used to better understand how our space environment interacts with the interstellar environment beyond the heliopause," said Eric Christian, IBEX program scientist at NASA's Goddard Space Flight Center in Greenbelt, Maryland, who was not involved in this study. "In turn, understanding that interaction could help explain the mystery of what causes the IBEX ribbon once and for all."

The Southwest Research Institute leads IBEX with teams of national and international partners. NASA Goddard manages the Explorers Program for the agency's Heliophysics Division within the Science Mission Directorate in Washington.



Contacts and sources:
Karen Fox 
NASA's Goddard Space Flight Center

Thursday, February 25, 2016

Galaxy Trailed By Stunning Plume Of Gas I


Astronomers have discovered a spectacular tail of gas more than 300,000 light years across coming from a nearby galaxy.

The plume is made up of hydrogen gas--the material new stars are made of--and is five times longer than the galaxy itself.

The foreground galaxy is NGC 4569 of the Virgo cluster. The red filaments to the right of the galaxy show the hydrogen gas that has been removed. The tail represents about 95 per cent of the gas reservoir the galaxy needs to feed the formation of new stars.

Credit: CFHT/Coelum

The discovery was made by an international team of scientists led by Dr Alessandro Boselli at the Laboratoire d'Astrophysique de Marseille in France, and published in the journal Astronomy & Astrophysics.

International Centre for Radio Astronomy Research astrophysicist Luca Cortese, who is part of the research team, said scientists noticed long ago that the galaxy NGC 4569 contained less gas than expected but they could not see where it had gone.

"We didn't have the smoking gun, the clear evidence of direct removal of gas from the galaxy," he said.

"Now, with these observations, we've seen a huge amount of gas that creates a stream trailing behind the galaxy for the first time.

"What's very nice is that if you measure the mass of the stream, it's the same amount of gas that is missing from the galaxy's disc."

NGC 4569 sits in the Virgo cluster, a group of galaxies 55 million light years from our own Milky Way.

It is travelling through the cluster at about 1200 kilometres a second, and Dr Cortese said it is this movement that is causing the gas to be stripped from the galaxy.

"We know that big clusters of galaxies trap a lot of hot gas," he said.

"So when a galaxy enters the cluster it feels the pressure of all the gas, like when you feel the wind on your face, and that pressure is able to strip matter away from the galaxy."

The discovery was made when the research team used a super-sensitive camera on the Canada France Hawaii Telescope to observe NGC 4569 for longer than ever before.

Dr Cortese said it could be the first of many galaxies found to have long tails of gas extending from them.

"It's pretty exciting because this was just a pilot and we only targeted the brightest spiral galaxy in the Virgo cluster," he said.

"We were amazed by what we got... this is really promising because it means it's very likely we'll find similar features in many other galaxy clusters."


Contacts and sources:
Dr Luca Cortese  ICRAR/University of Western Australia  
Pete Wheeler, ICRAR
nternational Centre For Radio Astronomy Research

Citation: 'Spectacular tails of ionised gas in the Virgo cluster galaxy NGC 4569' published in Astronomy & Astrophysics on February 19, 2016. A copy of the paper is available from http://www.aanda.org/articles/aa/pdf/2016/03/aa27795-15.pdf



Zika Virus Linked to Stillbirth, Other Symptoms in Brazil

A pregnant Brazilian woman infected with the Zika virus had a stillborn baby in January who had signs of severe tissue swelling as well as central nervous system defects that caused the cerebral hemispheres of the brain to be absent. It is the first report to indicate a possible association of congenital Zika virus and damage to tissues outside the central nervous system.

2016 Zika virus infections worldwide
File:Zika virus infections worldwide.svg
Credit: Wikimedia Commons

Researchers led by Albert Ko, M.D. of the Yale School of Public Health and Dr. Antônio Raimundo de Almeida at the Hospital Geral Roberto Santos in Salvador, Brazil, describe the case in the current issue of the journal PLOS Neglected Tropical Diseases.

Ko and colleagues said the case provides evidence that, in addition to microcephaly, (a condition marked by an abnormally small head in newborns and widely linked to the Zika outbreak in Brazil), congenital Zika infection may also be linked to hydrops fetalis (abnormal accumulation of fluid in fetal compartments), hydranencephaly (almost complete loss of brain tissue) and fetal demise (stillbirth).

File:ZIKA.png
Credit: Beth Herlin/Wikimedia Commons

The researchers said that it is not possible to extrapolate from a single case the overall risk for these outcomes faced by women who are exposed to the virus during pregnancy.

"These finding raise concerns that the virus may cause severe damage to fetuses leading to stillbirths and may be associated with effects other than those seen in the central nervous system," said Ko, chair of the Department of Epidemiology of Microbial Diseases, who has worked on the Zika outbreak in the coastal city of Salvador with Brazilian colleagues since shortly after the first cases of the mosquito-borne virus were reported there in early 2015. "Additional work is needed to understand if this is an isolated finding and to confirm whether Zika virus can actually cause hydrops fetalis."

Zika arm rash
File:Zika.Virus.Rash.Arm.2014.jpg
Credit:  Wikimedia Commons

The patient, a 20-year-old woman, was having a normal pregnancy during her first trimester. That changed abruptly during the course of the 18th week of pregnancy, when an ultrasound examination discovered that the fetus' weight was well below where it should have been at that point.

The woman did not report any of the symptoms commonly associated with Zika (rash, fever, or body aches) prior to or during the early stages or her pregnancy, the researchers said. She also did not exhibit symptoms of other mosquito-borne diseases, including dengue or chikungunya.

By the 30th week of the pregnancy, the fetus showed a range of birth defects. Labor was induced at the 32nd week. Researchers subsequently confirmed the presence of the Zika virus in the fetus. The strain of Zika that was found appears to be the same strain that is currently spreading elsewhere.

Since Zika appeared in Brazil, the virus has spread rapidly throughout much of Latin America and into the Caribbean. Several cases have also been confirmed in the United States.

The researchers said that since it is likely that large numbers of pregnant women in Brazil and beyond will be exposed to the same Zika strain as the woman in the case study, further investigations are needed to determine the risk of stillbirth and the other adverse outcomes.

Ko worked on the study with colleagues from the Hospital Geral Roberto Santos in Salvador, the Universidade Federal da Bahia in Salvador, the Oswaldo Cruz Foundation in Salvador and the University of Texas Medical Branch in Galveston.





Contacts and sources:
Michael Greenwood
PLOS Neglected Tropical Diseases

Citation: Kaltenbach LS et al. (2007) Huntington Interacting Proteins Are Genetic Modifiers of Neurodegeneration.PLOS Genet 3(5): e82. doi:10.1371/journal.pgen.0030082 http://dx.plos.org/10.1371/journal.pntd.0004517 

TAU Discovers Extensive Fabric Collection Dating Back to Kings David and Solomon

Textiles found at Timna Valley archaeological dig by Tel Aviv University researchers provide a colorful picture of a complex society during the time of  Kings David and Solomon.

The ancient copper mines in Timna are located deep in Israel's Arava Valley and are believed by some to be the site of King Solomon's mines. The arid conditions of the mines have seen the remarkable preservation of 3,000-year-old organic materials, including seeds, leather and fabric, and other extremely rare artifacts that provide a unique window into the culture and practices of this period.

 A fine wool textile dyed red and blue, found at Timna. The textile used the various colors of natural animal hair to create black and orange-brown colors for decorative bands.
 
Photo by Clara Amit, courtesy of the Israel Antiquities Authority.

A Timna excavation team from Tel Aviv University led by Dr. Erez Ben-Yosef has uncovered an extensive fabric collection of diverse color, design and origin. This is the first discovery of textiles dating from the era of David and Solomon, and sheds new light on the historical fashions of the Holy Land. The textiles also offer insight into the complex society of the early Edomites, the semi-nomadic people believed to have operated the mines at Timna.

The tiny pieces of fabric, some only 5 x 5 centimeters in size, vary in color, weaving technique and ornamentation. "Some of these fabrics resemble textiles only known from the Roman era," said Dr. Orit Shamir, a senior researcher at the Israel Antiquities Authority, who led the study of the fabrics themselves.

"No textiles have ever been found at excavation sites like Jerusalem, Megiddo and Hazor, so this provides a unique window into an entire aspect of life from which we've never had physical evidence before," Dr. Ben-Yosef said. "We found fragments of textiles that originated from bags, clothing, tents, ropes and cords.

"The wide variety of fabrics also provides new and important information about the Edomites, who, according to the Bible, warred with the Kingdom of Israel. We found simply woven, elaborately decorated fabrics worn by the upper echelon of their stratified society. Luxury grade fabric adorned the highly skilled, highly respected craftsmen managing the copper furnaces. They were responsible for smelting the copper, which was a very complicated process."

A trove of the "Seven Species"

The archaeologists also recently discovered thousands of seeds of the Biblical "Seven Species" at the site — the two grains and five fruits considered unique products of the Land of Israel. Some of the seeds were subjected to radiocarbon dating, providing robust confirmation for the age of the site.

"This is the first time seeds from this period have been found uncharred and in such large quantities," said Dr. Ben-Yosef. "With the advancement of modern science, we now enjoy research options that were unthinkable a few decades ago. We can reconstruct wine typical of King David's era, for example, and understand the cultivation and domestication processes that have been preserved in the DNA of the seed."

The power of copper

Copper was used to produce tools and weapons and was the most valuable resource in ancient societies. Its production required many levels of expertise. Miners in ancient Timna may have been slaves or prisoners — theirs was a simple task performed under difficult conditions. But the act of smelting, of turning stone into metal, required an enormous amount of skill and organization. The smelter had to manage some 30 to 40 variables in order to produce the coveted copper ingots.

"The possession of copper was a source of great power, much as oil is today," Dr. Ben-Yosef said. "If a person had the exceptional knowledge to 'create copper,' he was considered well-versed in an extremely sophisticated technology. He would have been considered magical or supernatural, and his social status would have reflected this."

To support this "silicon valley" of copper production in the middle of the desert, food, water and textiles had to be transported long distances through the unforgiving desert climate and into the valley. The latest discovery of fabrics, many of which were made far from Timna in specialized textile workshops, provides a glimpse into the trade practices and regional economy of the day.

"We found linen, which was not produced locally. It was most likely from the Jordan Valley or Northern Israel. The majority of the fabrics were made of sheep's wool, a cloth that is seldom found in this ancient period," said TAU masters student Vanessa Workman. "This tells us how developed and sophisticated both their textile craft and trade networks must have been."

"'Nomad' does not mean 'simple,'" said Dr. Ben-Yosef. "This discovery strengthens our understanding of the Edomites as an important geopolitical presence. The fabrics are of a very high quality, with complex designs and beautiful dyes."



Contacts and sources:
George Hunka
Tel Aviv University

The Prolonged Death of Light from Type Ia Supernovae


New supernova observations reveal extended brightness, could help researchers better understand invaluable cosmology tool.

Three years after its explosion, a type Ia supernova continues to shine brighter than expected, new research finds. The observations, made with the Hubble Space Telescope and published today in The Astrophysical Journal, suggest that the powerful explosions produce an abundance of a heavy form of cobalt that gives the heat from nuclear decay an extra energy boost. The work could help researchers pinpoint the parents of type Ia supernovae--a type of stellar explosion that is frequently used to measure distances to faraway galaxies--and reveal the mechanics behind these explosions.

AMNH researchers make a discovery about the chemical composition of Type Ia supernovae, which may aid in the understanding of how these stars explode—and become the “standard candles” by which we measure the distance of far-off galaxies.
Credit: American Museum of Natural History

"Type Ia supernovae became very important to physics, as a whole, a couple of decades ago when they were used to show that the expansion of the universe is accelerating," said lead author Or Graur, a research associate in the American Museum of Natural History's Department of Astrophysics and a postdoctoral researcher at New York University. "Yet we still do not know exactly what type of star system explodes as a type Ia supernova or how the explosion takes place. A lot of research has gone into these two questions, but the answers are still elusive."

Current research indicates that type Ia supernova explosions originate from binary star systems--two stars orbiting one another--in which at least one star is a white dwarf, the dense remains of a star that was a few times more massive than our Sun. The explosion is the result of a thermonuclear chain reaction, which produces a large amount of heavy elements. 

A Hubble Space Telescope image of galaxy NGC 4424, which is about 50 million light years away, and close-ups of the type Ia supernova the research team observed. In the upper left, the difference in the brightness of the supernova is shown about a year apart.

Credit: NASA / Hubble Space Telescope

The light that researchers see when a type Ia supernova explodes comes from the radioactive decay of an isotope of nickel (56Ni) into an isotope of cobalt (56Co) and then into a stable isotope of iron (56Fe). Although peak brightness is reached relatively quickly, and most researchers stop watching supernovae after about 100 days past the beginning of the explosion, the light continues to radiate for years.

Previous studies predicted that about 500 days after an explosion, researchers should see a sharp drop-off in the brightness of these supernovae, an idea called the "infrared catastrophe." However, no such drop-offs have been observed, so Ivo Seitenzahl, a researcher at the Australian National University and the ARC Centre of Excellence for All-sky Astrophysics and one of the co-authors on the paper, predicted in 2009 that it must be due to the radioactive decay of 57Co. This is a heavier isotope of cobalt with a longer half-life than 56Co, and it is expected to provide an extra energy source that would kick in around two to three years after the explosion.

The researchers tested the prediction directly by using the Hubble Space Telescope to observe the type Ia supernova SN 2012cg more than three years after it exploded in the galaxy NGC 4424, which is about 50 million light years away--nearby in astronomical terms.

"We saw the supernova's brightness evolve just as Ivo predicted," Graur said. "Interestingly, though, we found that the amount of 57Co needed to produce the observed brightness was about twice the amount expected. These two pieces of information provide fresh constraints on progenitor and explosion models. Stated differently, we now have a new piece in the puzzle that is type Ia supernovae, one of the most important tools in modern cosmology."

"When we made our prediction in 2009, I was skeptical whether clues for the presence of 57Co in type Ia supernovae would be observed in my lifetime," Seitenzahl said. "I am absolutely thrilled that now, only seven years later, we are already constraining explosion scenarios based on our measurements."

There is one caveat to the results: The excess brightness measured by the researchers could be due to a phenomenon known as a "light echo" instead of 57Co. A light echo happens when light from an explosion interacts with a large dust cloud, which scatters the light in all directions. In that case, light from the explosion would reach Earth twice: once directly from the supernova and then many years later as the result of the echo. To rule out the possibility of the light coming from an echo, more observations will have to be made of type Ia supernovae that are closer to Earth.

Other authors on the paper include Michael Shara and David Zurek, American Museum of Natural History; Adam Riess, The Johns Hopkins University and Space Telescope Science Institute; and Armin Rest, Space Telescope Science Institute.


Contacts and sources: 
Kendra Snyder
The American Museum of Natural History 

Citation:  Astrophysical Journal paper: http://iopscience.iop.org/article/10.3847/0004-637X/819/1/31

Surprising Variability in Shape of Van Allen Belts Findings Could Impact How We Protect Technology in Space

The shape of the two electron swarms 600 miles to more than 25,000 miles from the Earth's surface, known as the Van Allen Belts, could be quite different than has been believed for decades, according to a new study of data from NASA's Van Allen Probes that was released Friday in the Journal of Geophysical Research. 

"The shape of the belts is actually quite different depending on what type of electron you're looking at," said Geoff Reeves of Los Alamos National Laboratory's Intelligence and Space Research Division and lead author on the study. "Electrons at different energy levels are distributed differently in these regions."

Learn about the Van Allen Belts and how new findings from NASA's Van Allen Probes could impact how we protect technology in space.

Credit: Los Alamos National Laboratory

Understanding the shape and size of the belts, which shrink and swell in response to magnetic storms coming from the sun, is crucial for protecting our technology in space. The harsh radiation isn't good for satellite's health, so scientists want to know just which orbits could be jeopardized in different situations. Los Alamos has been studying space weather and its effects on national security satellites since the 1960s, when the U.S. launched the Vela satellites to support nuclear treaty verification.

Since scientists first began forming a picture of these rings of energetic particles in the 1950s, understanding of their shape has largely remained unchanged--a small, inner belt, a largely empty space known as the slot region, and then the outer belt, which is dominated by electrons and is larger and more dynamic than the others.

1. The traditional idea of the radiation belts includes a larger, more dynamic outer belt and a smaller, more stable inner belt with an empty slot region separating the two. However, a new study based on data from NASA's Van Allen Probes shows that all three regions--the inner belt, slot region, and outer belt -- can appear differently depending on the energy of electrons considered and general conditions in the magnetosphere.

2. At the highest electron energies measured -- above 1 MeV -- researchers saw electrons in the outer belt only.

Credit: NASA Goddard/Duberstein

3. The radiation belts look much different at the lowest electron energy levels measured, about 0.1 MeV. Here, the inner belt is much larger than in the traditional picture, expanding into the region that has long been considered part of the empty slot region. The outer belt is diminished and doesn't expand as far in these lower electron energies.

4. During geomagnetic storms, the empty region between the two belts can fill in completely with lower-energy electrons. Traditionally, scientists thought this slot region filled in only during the most extreme geomagnetic storms happening about once every ten years. However, new data shows it's not uncommon for lower-energy electrons -- up to 0.8 MeV -- to fill this space during almost all geomagnetic storms.
But this new analysis reveals that the shape varies from a single, continuous belt with no slot region, to a larger inner belt with a smaller outer belt, to no inner belt at all. Many of the differences are accounted for by considering electrons at different energy levels separately.

"It's like listening to different parts of a song," said Reeves. "The bass line sounds different from the vocals, and the vocals are different from the drums, and so on."

The authors of the study, from Los Alamos National Laboratory and the New Mexico Consortium, found that the inner belt--the smaller belt in the classic picture of the belts--is much larger than the outer belt when observing electrons with low energies, while the outer belt is larger when observing electrons at higher energies. At the very highest energies, the inner belt structure is missing completely. So, depending on what one focuses on, the radiation belts can appear to have very different structures simultaneously.

These structures are further altered by geomagnetic storms. When high-speed solar wind streams or coronal mass ejections--fast-moving magnetic material from the sun--collide with Earth's magnetic field, they send it oscillating, creating a geomagnetic storm. Geomagnetic storms can increase or decrease the number of energetic electrons in the radiation belts for days to months, though the belts return to their normal configuration after a time.

These storm-driven electron increases and decreases are currently unpredictable, without a clear pattern showing what type or strength of storm will yield what outcomes. There's a saying in the space physics community: if you've seen one geomagnetic storm, you've seen one geomagnetic storm. But, it turns out, those observations have largely been based on electrons at only a few energy levels.

"When we look across a broad range of energies, we start to see some consistencies in storm dynamics," said Reeves. "The electron response at different energy levels differs in the details, but there is some common behavior. For example, we found that electrons fade from the slot regions quickly after a geomagnetic storm, but the location of the slot region depends on the energy of the electrons."

Often, the outer electron belt expands inwards toward the inner belt during geomagnetic storms, completely filling in the slot region with lower-energy electrons and forming one huge radiation belt. At lower energies, the slot forms farther from Earth, producing an inner belt that is bigger than the outer belt. At higher energies, the slot forms closer to Earth, reversing the comparative sizes.

The twin Van Allen Probes satellites expand the range of energetic electron data we can capture. In addition to studying the extremely high-energy electrons--carrying millions of electron volts--that had been studied before, the Van Allen Probes can capture information on lower-energy electrons that contain only a few thousand electron volts. Additionally, the spacecraft measure radiation belt electrons at a greater number of distinct energies than was previously possible.

"Previous instruments would only measure five or ten energy levels at a time," said Reeves. "But the Van Allen Probes measure hundreds."

Measuring the flux of electrons at these lower energies has proved difficult in the past because of the presence of protons in the radiation belt regions closest to Earth. These protons shoot through particle detectors, creating a noisy background from which the true electron measurements needed to be picked out. But the higher-resolution Van Allen Probes data found that these lower-energy electrons circulate much closer to Earth than previously thought.

"Despite the proton noise, the Van Allen Probes can unambiguously identify the energies of the electrons they're measuring," said Reeves.

Precise observations like this, from hundreds of energy levels, rather than just a few, will allow scientists to create a more precise and rigorous model of what, exactly, is going on in the radiation belts, both during geomagnetic storms and during periods of relative calm.

"You can always tweak a few parameters of your theory to get it to match observations at two or three energy levels," said Reeves. "But having observations at hundreds of energies constrain the theories you can match to observations."



Contacts and sources: 
Laura Mullane
Los Alamos National Laboratory

Spectacular New Views of the Milky Way Released Following Galactic Survey

A spectacular new image of the Milky Way has been released to mark the completion of the APEX Telescope Large Area Survey of the Galaxy (ATLASGAL). 
Credit: ESO/APEX/ATLASGAL consortium/NASA/GLIMPSE consortium/ESA/Planck

The APEX telescope in Chile has mapped the full area of the Galactic Plane visible from the southern hemisphere at submillimetre wavelengths — between infrared light and radio waves. This is the sharpest such map yet made, and complements those from recent space-based surveys. The pioneering 12-metre APEX telescope allows astronomers to study the cold Universe: gas and dust only a few tens of degrees above absolute zero.

This video comparison shows the central regions of the Milky Way observed in four different wavelength ranges.

The first view shows compact sources of submillimetre radiation detected by APEX as part of the ATLASGAL survey, combined with complementary data from ESA’s Planck satellite, to capture more extended features.

The second view shows the same region as seen in shorter, infrared, wavelengths by NASA’s Spitzer Space Telescope as part of the GLIMPSE survey.

The third view shows the same part of sky again at even shorter wavelengths, the near-infrared, as seen by ESO’s VISTA infrared survey telescope at the Paranal Observatory in Chile. Regions appearing as dark dust tendrils here show up brightly in the ATLASGAL view.

Finally the more familiar view in visible light, when most of the more distant structures are hidden from view, is also included.

The significance of the colours varies from image to image and they cannot be directly compared.
Credit: ESO/APEX/ATLASGAL consortium/NASA/GLIMPSE consortium/ESA/Planck/VVV Survey/D. Minniti/S. Guisard Acknowledgement: Ignacio Toledo, Martin Kornmesser. Music: Johan B. Monell (www.johanmonell.com)

APEX, the Atacama Pathfinder EXperiment telescope, is located at 5100 metres above sea level on the Chajnantor Plateau in Chile’s Atacama region. The ATLASGAL survey took advantage of the unique characteristics of the telescope to provide a detailed view of the distribution of cold dense gas along the plane of the Milky Way galaxy [1]. The new image includes most of the regions of star formation in the southern Milky Way [2].
This comparison shows the central regions of the Milky Way observed at different wavelengths.

The top panel shows compact sources of submillimetre radiation detected by APEX as part of the ATLASGAL survey, combined with complementary data from ESA’s Planck satellite, to capture more extended features.

The second panel shows the same region as seen in shorter, infrared, wavelengths by the NASA Spitzer Space Telescope.

The third panel shows the same part of sky again at even shorter wavelengths, the near-infrared, as seen by ESO’s VISTA infrared survey telescope at the Paranal Observatory in Chile. Regions appearing as dark dust tendrils here show up brightly in the ATLASGAL view.

Finally the bottom picture shows the more familiar view in visible light, where most of the more distant structures are hidden from view.

The significance of the colours varies from image to image and they cannot be directly compared.
Comparison of the central part of the Milky Way at different wavelengths
Credit:  ESO/ATLASGAL consortium/NASA/GLIMPSE consortium/VVV Survey/ESA/Planck/D. Minniti/S. Guisard
Acknowledgement: Ignacio Toledo, Martin Kornmesser

The new ATLASGAL maps cover an area of sky 140 degrees long and 3 degrees wide, more than four times larger than the first ATLASGAL release [3]. The new maps are also of higher quality, as some areas were re-observed to obtain a more uniform data quality over the whole survey area.

The ATLASGAL survey is the single most successful APEX large programme with nearly 70 associated science papers already published, and its legacy will expand much further with all the reduced data products now available to the full astronomical community [4].

This video takes a close look at a new image of the Milky Way released to mark the completion of the APEX Telescope Large Area Survey of the Galaxy (ATLASGAL). The APEX telescope in Chile has mapped the full area of the Galactic Plane visible from the southern hemisphere for the first time at submillimetre wavelengths — between infrared light and radio waves — and in finer detail than recent space-based surveys.

The APEX data, at a wavelength of 0.87 millimetres, shows up in red and the background blue image was imaged at shorter infrared wavelengths by the NASA Spitzer Space Telescope as part of the GLIMPSE survey. The fainter extended red structures come from complementary observations made by ESA's Planck satellite.

Credit: ESO/APEX/ATLASGAL consortium/NASA/GLIMPSE consortium/ESA/Planck. Music: Johan B. Monell (www.johanmonell.com)

At the heart of APEX are its sensitive instruments. One of these, LABOCA (the LArge BOlometer Camera) was used for the ATLASGAL survey. LABOCA measures incoming radiation by registering the tiny rise in temperature it causes on its detectors and can detect emission from the cold dark dust bands obscuring the stellar light.

The new release of ATLASGAL complements observations from ESA's Planck and Herschel satellites [5]. The combination of the Planck and APEX data allowed astronomers to detect emission spread over a larger area of sky and to estimate from it the fraction of dense gas in the inner Galaxy. The ATLASGAL data were also used to create a complete census of cold and massive clouds where new generations of stars are forming.

A spectacular new image of the Milky Way has been released to mark the completion of the APEX Telescope Large Area Survey of the Galaxy (ATLASGAL). The APEX telescope in Chile has mapped the full area of the Galactic Plane visible from the southern hemisphere at submillimetre wavelengths — between infrared light and radio waves. The new finely detailed images complement those from recent space-based surveys. The pioneering 12-metre APEX telescope allows astronomers to study the cold Universe: gas and dust only a few tens of degrees above absolute zero.

The APEX data, at a wavelength of 0.87 millimetres, shows up in red and the background blue image was imaged at shorter infrared wavelengths by the NASA Spitzer Space Telescope as part of the GLIMPSE survey. The fainter extended red structures come from complementary observations made by ESA's Planck satellite.

Many of the most prominent objects are named and the parts of the galaxy that are shown in the three slices are indicated at the right.
The southern plane of the Milky Way from the ATLASGAL survey (annotated)
Credit:  ESO/APEX/ATLASGAL consortium/NASA/GLIMPSE consortium/ESA/Planck

“ATLASGAL provides exciting insights into where the next generation of high-mass stars and clusters form. By combining these with observations from Planck, we can now obtain a link to the large-scale structures of giant molecular clouds,” remarks Timea Csengeri from the Max Planck Institute for Radio Astronomy (MPIfR), Bonn, Germany, who led the work of combining the APEX and Planck data.

The APEX telescope recently celebrated ten years of successful research on the cold Universe. It plays an important role not only as pathfinder, but also as a complementary facility to ALMA, the Atacama Large Millimeter/submillimeter Array, which is also located on the Chajnantor Plateau. APEX is based on a prototype antenna constructed for the ALMA project, and it has found many targets that ALMA can study in great detail.

Leonardo Testi from ESO, who is a member of the ATLASGAL team and the European Project Scientist for the ALMA project, concludes: “ATLASGAL has allowed us to have a new and transformational look at the dense interstellar medium of our own galaxy, the Milky Way. The new release of the full survey opens up the possibility to mine this marvellous dataset for new discoveries. Many teams of scientists are already using the ATLASGAL data to plan for detailed ALMA follow-up.”


Contacts and sources:
Richard Hook 
ESO

LIGO's Twin Black Holes Might Have Been Born Inside a Single Star

On September 14, 2015, the Laser Interferometer Gravitational-wave Observatory (LIGO) detected gravitational waves from the merger of two black holes 29 and 36 times the mass of the Sun. Such an event is expected to be dark, but the Fermi Space Telescope detected a gamma-ray burst just a fraction of a second after LIGO's signal. New research suggests that the two black holes might have resided inside a single, massive star whose death generated the gamma-ray burst.

"It's the cosmic equivalent of a pregnant woman carrying twins inside her belly," says Harvard astrophysicist Avi Loeb of the Harvard-Smithsonian Center for Astrophysics (CfA).

On Sept. 14, 2015, LIGO detected gravitational waves from two merging black holes, shown here in this artist's conception. The Fermi space telescope detected a burst of gamma rays 0.4 seconds later. New research suggests that the burst occurred because the two black holes lived and died inside a single, massive star.
Credit: Swinburne Astronomy Productions

Normally, when a massive star reaches the end of its life, its core collapses into a single black hole. But if the star was spinning very rapidly, its core might stretch into a dumbbell shape and fragment into two clumps, each forming its own black hole.

A very massive star as needed here often forms out of the merger of two smaller stars. And since the stars would have revolved around each other faster and faster as they spiraled together, the resulting merged star would be expected to spin very quickly.

After the black hole pair formed, the star's outer envelope rushed inward toward them. In order to power both the gravitational wave event and the gamma-ray burst, the twin black holes must have been born close together, with an initial separation of order the size of the Earth, and merged within minutes. The newly formed single black hole then fed on the infalling matter, consuming up to a Sun's worth of material every second and powering jets of matter that blasted outward to create the burst.

Fermi detected the burst just 0.4 seconds after LIGO detected gravitational waves, and from the same general area of the sky. However, the European INTEGRAL gamma-ray satellite did not confirm the signal.

"Even if the Fermi detection is a false alarm, future LIGO events should be monitored for accompanying light irrespective of whether they originate from black hole mergers. Nature can always surprise us," says Loeb.

If more gamma-ray bursts are detected from gravitational wave events, they will offer a promising new method of measuring cosmic distances and the expansion of the universe. By spotting the afterglow of a gamma-ray burst and measuring its redshift, then comparing it to the independent distance measurement from LIGO, astronomers can precisely constrain the cosmological parameters. "Astrophysical black holes are much simpler than other distance indicators, such as supernovae, since they are fully defined just by their mass and spin," says Loeb.

"This is an agenda-setting paper that will likely stimulate vigorous follow-up work, in the crucial period after the initial LIGO discovery, where the challenge is to fathom its full implications. If history is any guide, the 'multi-messenger' approach advocated by Loeb, using both gravitational waves and electromagnetic radiation, again promises deeper insight into the physical nature of the remarkable LIGO source," says Volker Bromm of the University of Texas at Austin, commenting independently.



Contacts and sources:
Christine Pulliam  
Harvard-Smithsonian Center for Astrophysics  

Monday, February 22, 2016

Sharks Are Surprisingly Social

Although historically seen as solitary animals, new research being presented here shows sharks may have a more complex social structure than previously thought. Using tracking devices to trace the movements of individual animals in the open ocean, researchers found that Sand Tiger sharks form complex social networks that are typically seen in mammals but rarely observed in fish.

Sand Tiger sharks congregate together in the shallow waters of the Delaware Bay in summertime. Researchers at the University of Delaware in Lewes use acoustic tags to track the movements of individual Sand Tigers in the open ocean throughout the rest of the year.
Credit: Danielle Haulsee.

“Higher-order decision-making processes are often associated with mammals, or species that we think of as really smart – dolphins, elephants, or chimpanzees,” said Danielle Haulsee, a PhD candidate in oceanography at the University of Delaware in Lewes. “Our research shows that it is important for the scientific community to not rule out these types of behaviors in non-mammalian species, as behavior can often give us insight on how species interact with their ecosystems and how resources that humans depend on are distributed around the world.”

Sand Tiger sharks, top predators that live in coastal waters off the Eastern United States, have experienced drastic population declines over the past several decades. Sand tigers are important regulators of marine food webs but have been historically understudied, according to Haulsee.

In the summer, Sand Tigers congregate together in the shallow waters of the Delaware Bay, but little is known about their movements and how they interact with one another in the open ocean during the rest of the year, Haulsee said. Understanding how these sharks move and interact could help biologists better conserve this species and determine how vulnerable they are to human activities such as fishing and dredging.

Haulsee and her research team used acoustic tags to track the movements of over 300 individual Sand Tiger sharks and record shark-shark interactions over the course of a year. Previous studies have looked at shark interactions in laboratories or species contained in pens, but this the first study to record interactions for almost a year in free-swimming sharks, Haulsee said.

Initial data from two individual sharks show they encountered nearly 200 other sand tigers throughout the year, as well as several individuals from other shark species.

These sharks exhibit fission-fusion social behavior, meaning that the number of sharks in a group and the individuals that are part of the group change by location and time of year. Haulsee and her team found that groups of Sand Tigers stay together for certain times of the year and fall apart during other times. They also found that Sand Tigers re-encounter the same sharks throughout the year.

One surprise was a sudden lack of encounters with other Sand Tigers in the late winter and early spring, Haulsee said. Up until that point, both Sand Tigers were encountering other sharks regularly, but in the late winter, both seemed to enter a dispersal phase where they encountered very few other sharks. According to Haulsee, this could be related to other aspects of the sharks’ lives, such as mating and searching for food, which suggests that they could be performing a kind of social cost-benefit analysis.

Although this type of social behavior has been suggested in sharks before, the change in the group composition on an individual basis has not been documented in this way, according to Haulsee.

Danielle Haulsee, PhD candidate in oceanography at the University of Delaware in Lewes, and colleagues implant an acoustic receiver into a Sand Tiger shark resting in a sling.

Credit: Cara Simpson.

“If you’re living with a group, there could be some kind of protection or information sharing that comes with being in that group,” she said. “But if there’s a lot of competition for food resources or mating resources, then it’s not beneficial anymore to be in a group, and you might swim away from your group and go off on your own.”

Haulsee will be presenting initial data from the study today at the 2016 Ocean Sciences Meeting co-sponsored by the Association for the Sciences of Limnology and Oceanography, The Oceanography Society and the American Geophysical Union.

The researchers hope to use their results to answer questions about whether Sand Tigers form family groups or whether sharks of similar size and sex form distinct groupings. They also hope that defining critical locations where sharks congregate together will help build conservation plans to better protect this species.

“If we know where and when the population is grouped, we can focus on limiting human-induced disturbances in those times and places,” Haulsee said. “For example, if we know there are certain times and places where breeding females, or even more importantly the pregnant females, are aggregated together, we can devote resources into those areas to protect those sharks.”


Contacts and sources: 
Nanci Bompey, American Geophysical Union

Gulf of Mexico Historic Shipwrecks Help Scientists Unlock Mysteries of Deep-Sea Ecosystems

The 2010 Deepwater Horizon oil spill significantly altered microbial communities thriving near shipwrecks in the Gulf of Mexico, potentially changing these diverse ecosystems and degrading the historically and culturally significant ships they live on, according to new research being presented here.

The findings are also revealing how decades-old, or even centuries-old, shipwrecks could be used to monitor the health of deep-ocean ecosystems, and the effects of oil and gas activity in the Gulf, according to the researchers.

There are more than 2,000 known historic shipwrecks sitting on the ocean floor in the Gulf of Mexico, spanning some 500 years of maritime history: from the time of the 16th century Spanish explorers to the American Civil War and through the World War II era. In addition to their historical and cultural significance, historic shipwrecks also serve as artificial reefs, supporting a rich deep-sea ecosystem.

There are more than 2,000 known historic shipwrecks sitting on the ocean floor in the Gulf of Mexico, spanning some 500 years of maritime history: from the time of the 16th century Spanish explorers to the American Civil War and through the World War II era. In addition to their historical and cultural significance, historic shipwrecks also serve as artificial reefs, supporting a rich deep-sea ecosystem.

A 3D laser scan of the stern section of the German U-boat,U-166, that sunk in the Gulf of Mexico during World War II. The scan shows the U-boat’s conning tower and the build-up of sediments around the hull. Scientists will use this data to document changes at the shipwreck sites, including areas of hull collapse or weakening, and other site-formation processes.
Credit: BOEM/C&C Technologies, In

In 2014, a multidisciplinary team of scientists launched a project investigating the effects of the Deepwater Horizon oil spill on shipwrecks that lie hundreds to thousands of feet underwater and the microbial communities forming the base of these ecosystems. The project is the first of its kind to study deep-sea shipwreck microbiomes, and the long-term impacts of an oil spill on shipwrecks and their microbial inhabitants, according to the researchers. (See a video of the research here)

“We are filling a huge void in our scientific understanding of the impacts of the spill,” said Melanie Damour, a marine archaeologist at the Bureau of Ocean Energy Management in New Orleans, Louisiana, and a co-leader of the project.

Scientists found that the presence of a shipwreck influences which microbes are present on the seafloor, and the release of 4 million barrels of oil from the Macondo well for 87 days significantly altered nearby shipwreck microbial communities. Even four years after the event, the oil was still affecting the community structure and function of these microbes, potentially impacting other parts of the ecosystem. Laboratory studies found that the dispersant used to clean up the oil spill significantly alters the shipwreck microbial community that forms the foundation for other life, like coral, crabs and fish, which thrive there.

Bow of the Ewing Bank Wreck, a 19th century wooden-hulled sailing ship that lies in more than 600 meters (2,000 feet) of water. The image shows a close-up view of the copper sheathing attached to the outside of the wooden hull. After the vessel sank, it became a vibrant artificial reef now colonized by Lophelia pertusa coral (white), Venus flytrap anemones, and many other species of macrofauna.
Credit: BOEM/Deep Sea Systems International

Not only did these studies show that the spill affected these ecosystems, but they also provide a new way to monitor the spill’s effects, said Leila Hamdan, a microbial ecologist at George Mason University in Manassas, Virginia and co-leader of the project.

“The microorganisms in these deep-water habitats, where these artificial reefs are present, they make life habitable, make it luxurious, in a place that is cold and dark and permanently separated from light,” she said. “If we are performing activities in the ocean that potentially change these extremely important communities, we should know about that.”

The laboratory studies also found that oil exposure increases metal corrosion caused by microbes, showing that the oil spill could potentially speed up degradation of the steel-hulled shipwrecks, according to Jennifer Salerno, a microbial ecologist at George Mason University.

Wood sample collected from the Mardi Gras shipwreck site, which sank some 200 years ago about 56 kilometers (35 miles) off the coast of Louisiana in 1,220 meters (4,000 feet) of water. A wood sample yields important clues about wood species, degradation in the local environment, and potential exposure to hydrocarbons or other contaminants.
Credit: BOEM/Melanie Damour

The team also used innovative 3-D laser and sonar technology to obtain high-resolution images of the vessels to document their current state of preservation. In one case, a World War II German U-boat that has been previously examined several times since its discovery in 2001 was found to be buried by more sediment than was observed prior to the spill, although the researchers are working to determine if it was a natural process or related to the oil spill. The team plans to repeatedly scan the shipwrecks to document how they change over time.

“These are pieces of our collective human history down there and they are worth protecting,” said Damour, adding that in some cases these ships may still contain human remains. “We are concerned that the degradation of these sites a lot faster than normal will cause the permanent loss of information that we can never get back.”

Members of the project team will be presenting their new research today at the 2016 Ocean Sciences Meeting co-sponsored by the Association for the Sciences of Limnology and Oceanography, The Oceanography Society and the American Geophysical Union.

The new findings show that deep-sea shipwrecks could be used for long-term monitoring of deep-sea ecosystems, according to the researchers. Understanding this unique ecosystem could aid in protecting and conserving it – both the animals that live on the shipwrecks, and the ships themselves, they said. Information about these shipwrecks could also aid scientists who research the deep sea, and companies performing activities there, the researchers said.

For Hamdan, the experience of working on the shipwreck project has been transformative. “I will never forget the sensation I had when the ROV flew across the dark seafloor, an already beautifully muddy landscape, and suddenly there was a shipwreck, with all of its history and ecology before my eyes,” she said recalling the project’s first expedition in 2014. “It really changed me as a scientist … In a single instant I knew that there was more to the seafloor than I ever really considered.”



Contacts and sources: 
Nanci Bompey, American Geophysical Union

Bats' Super Immunity May Hold Key To Fighting Deadly Diseases Like Ebola and MERS

For the first time researchers have uncovered a unique ability in bats which allows them to carry but remain unaffected by lethal diseases.

Unlike humans, bats keep their immune systems switched on 24/7 and scientists believe this could hold the key to protecting people from deadly diseases like Ebola.

Bats are a natural host for more than 100 viruses, some of which are lethal to people, including Middle Eastern Respiratory Syndrome (MERS), Ebola and Hendra virus, however, interestingly bats do not get sick or show signs of disease from these viruses.

Credit: CSIRO

Published   in the journal Proceedings of the National Academy of Sciences (PNAS), this new research examines the genes and immune system of the Australian black flying fox, with surprising results.

"Whenever our body encounters a foreign organism, like bacteria or a virus, a complicated set of immune responses are set in motion, one of which is the defense mechanism known as innate immunity," leading bat immunologist at CSIRO's Australian Animal Health Laboratory Dr Michelle Baker said.

"We focused on the innate immunity of bats, in
particular the role of interferons - which are integral for innate immune responses in mammals - to understand what's special about how bats respond to invading viruses.

"Interestingly we have shown that bats only have three interferons which is only a fraction - about a quarter - of the number of interferons we find in people.

"This is surprising given bats have this unique ability to control viral infections that are lethal in people and yet they can do this with a lower number of interferons."

The team also compared two type 1 interferons - alpha and beta.

The research showed that bats express a heightened innate immune response even when they were not infected with any detectable virus.

"Unlike people and mice, who activate their immune systems only in response to infection, the bats interferon-alpha is constantly 'switched on' acting as a 24/7 front line defence against diseases," Dr Baker said.

Credit: CSIRO

"In other mammalian species, having the immune response constantly switched on is dangerous - for example it's toxic to tissue and cells - whereas the bat immune system operates in harmony."

While we are familiar of the important role bats play in the eco-system as pollinators and insect controllers, they are also increasingly demonstrating their worth in potentially helping to protect people from infectious diseases.

"If we can redirect other species' immune responses to behave in a similar manner to that of bats, then the high death rate associated with diseases, such as Ebola, could be a thing of the past," Dr Baker said.

This work builds on previous research undertaken by CSIRO and its partners to better understand bat immunity to help protect Australia and its people from exotic and emerging infectious diseases.


Contacts and sources:
CSIRO 

Apple Leftovers Make Better Batteries.

A carbon-based active material produced from apple leftovers and a material of layered oxides might help reduce the costs of future energy storage systems. Both were found to have excellent electrochemical properties and stand for the environmentally compatible and sustainable use of resources.

Now, these materials are presented by researchers of the Helmholtz Institute Ulm of Karlsruhe Institute of Technology in the journals “ChemElectroChem” and “Advanced Energy Materials.”

Sodium-ion batteries are not only far more powerful than nickel-metal hydride or lead acid accumulators, but also represent an alternative to lithium-ion technology, as the initial materials needed are highly abundant, easily accessible, and available at low cost. Hence, sodium-ion batteries are a very promising technology for stationary energy storage systems that play a central role in the transformation of the energy system and will be a highly attractive market in the future.

The new carbon-based material for sodium-ion batteries can be extracted from apples.   
Photo: KIT/HIU

Now, researchers of the team of Professor Stefano Passerini and Dr. Daniel Buchholz of the Helmholtz Institute Ulm of Karlsruhe Institute of Technology have made an important step towards the development of active materials for sodium-based energy storage systems. For the negative electrode, a carbon-based material was developed, which can be produced from the leftovers of apples and possesses excellent electrochemical properties. 

So far, more than 1000 charge and discharge cycles of high cyclic stability and high capacity have been demonstrated. This discovery represents an important step towards the sustainable use and exploitation of resources, such as organic waste.

Schematic structure of the layered oxides produced. 

Photo: KIT/HIU


The material developed for the positive electrode consists of several layers of sodium oxides. This active material goes without the expensive and environmentally hazardous element cobalt that is frequently used in active materials of commercial lithium-ion batteries. At the laboratory, the new active material, in which electrochemical energy storage proper takes place, reaches the same efficiency, cyclic stability, capacity, and voltage without any cobalt.

Both materials mark an important step towards the development of inexpensive and environmentally friendly sodium-ion batteries. The results are presented in two expert journals:

The HIU was established in January 2011 by KIT, member of the Helmholtz Association, in cooperation with Ulm University. With the German Aerospace Center (DLR) and the Center for Solar Energy and Hydrogen Research Baden-Württemberg (ZSW), two other renowned institutions are involved in the HIU as associated partners. The international team of about 125 scientists at HIU works on the further development of the fundamentals of viable energy storage systems for stationary and mobile use.




Contacts and sources:
Daniel Messling
Monika Landgraf
Karlsruhe Institute of Technology



Citation:  "Apple Biowaste-Derived Hard Carbon as a Powerful Anode Material for Na-Ion Batteries“ ChemElectroChem, doi: 10.1002/celc.201500437;

Citation:  “Layered Na-Ion Cathodes with Outstanding Performance Resulting from the Synergetic Effect of Mixed P- and O-type Phases” Advanced Energy Materials, doi: 10.1002/aenm.201501555. 

Sunday, February 21, 2016

Prehistoric Village Found in the Jordan Valley Links Old and New Stone Ages

Newly-excavated village in the Jordan Valley sheds light on the historical shift from foraging to agriculture, say Hebrew University of Jerusalem archaeologists.

Archaeologists from The Hebrew University of Jerusalem revealed in Israel a prehistoric village, dated around 12,000 years ago, in excavations in the fertile Jordan Valley.

The site, named NEG II, is located in Nahal (wadi) Ein-Gev, at the middle of the perennial stream that flows west to the Sea of Galilee.

NEG II nestled in the Jordan Valley 
Credit: Austin (Chad) Hill ©Leore Grosman

A series of excavations on site revealed an abundance of findings, including human burial remains, flint tools, art manifestations, faunal assemblage, ground stone and bone tools. The excavated area revealed an extensive habitation with deep cultural deposits (2.5 to 3 meters deep) and the site is estimated as covering roughly 1200 m2.

Surprisingly, the village differs markedly from others of its period in Israel. The findings encapsulate cultural characteristics typical of both the Old Stone Age -- known as the Paleolithic period, and the New Stone Age -- known as the Neolithic period.

“Although attributes of the lithic tool kit found at NEG II places the site chronologically in the Paleolithic period, other characteristics – such as its artistic tradition, size, thickness of archaeological deposits and investment in architecture – are more typical of early agricultural communities in the Neolithic period,” said Dr. Leore Grosman, from the Institute of Archaeology at The Hebrew University of Jerusalem, who led the excavations.

“Characterizing this important period of potential overlap in the Jordan Valley is crucial for the understanding of the socioeconomic processes that marked the shift from Paleolithic mobile societies of hunter-gatherers to Neolithic agricultural communities,” added Dr. Grosman. 

Excavations revealed buildings of a Natufian village  
Credit: Dr. Leore Grosman

The Paleolithic period is the earliest and the longest period in the history of mankind. The end of this period is marked by the transition to settled villages and domestication of plants and animals as part of the agricultural life-ways in the Neolithic period.

In a research, published in the journal PLOS ONE, the archeologists described the village as one of the latest settlements in the Levant region of the Late Natufian - the last culture of the Paleolithic period.

The Natufian culture (about 15,000-11,500 years B.P.) is known from sites all over the Levant – from the Negev and the Sinai in the south to Syria and Lebanon in the north.

NEG II was occupied in the midst of the cold and dry global climatic event known as the Younger Dryas (12,900–11,600 years B.P.), where temperature declined sharply over most of the northern hemisphere. Affected by climatic changes, Late Natufian groups in the Mediterranean zone became increasingly mobile and potentially smaller in size.

However, excavations at NEG II show that groups in the Jordan Valley became more sedentary and potentially larger in size.

"The buildings represent at least four occupational stages and the various aspects of the faunal assemblage provide good indications for site permanence. In addition, the thick archaeological deposits, the uniformity of the tool types and the flint knapping technology indicate intensive occupation of the site by the same cultural entity," said Dr. Grosman.

Researchers say that this shift in settlement pattern could be related to greater climatic stability due to a lesser effect of the Younger Dryas in the region, higher cereal biomass productivity and better conditions for small-scale cultivation.

These factors had provided the ingredients necessary to taking the final steps toward agriculture in the southern Levant, researchers say.

“It is not surprising that at the very end of the Natufian culture, at a suite of sites in the Jordan Valley, that we find a cultural entity that bridges the crossroads between Late Paleolithic foragers and Neolithic farmers,” said Dr. Grosman.




Contacts and sources: 
Hebrew University of Jerusalem

Citation:  Grosman L, Munro ND, Abadi I, Boaretto E, Shaham D, Belfer-Cohen A, et al. (2016) Nahal Ein Gev II, a Late Natufian Community at the Sea of Galilee. PLoS ONE 11(1): e0146647. doi:10.1371/ journal.pone.0146647