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Tuesday, February 9, 2016

A Deep Look Into A Single Molecule

The quantum state of a molecular ion has been measured live and in a non-destructive fashion for the first time.  

The interaction of thermal energy from the environment with motional degrees of freedom is well known and often referred to as Brownian motion (also thermal motion). But in the case of polar molecules, the internal degrees of freedom - in particular the rotational quantum state - are also influenced by the thermal radiation. So far, the detection of the rotational state was only possible by destroying the molecule. 

However, a German research group has now demonstrated the first implementation of a non-destructive state detection technique for molecular ions. Piet Schmidt and his colleagues from the QUEST-Institute at the Physikalisch-Technische Bundesanstalt (PTB) observed changes in the rotational state of a trapped and indirectly cooled molecular ion in real time and in situ. This technique enables novel spectroscopy methods with applications ranging from chemistry to tests of fundamental physics. The results are published in the current issue of "Nature".

Basic concept of the experiment: MgH+ (orange) and Mg+ (green) are trapped together in a linear ion trap. The two-ion compound is cooled to the motional ground state via the atomic ion. An oscillating dipole force changes the motional state according to the rotational state of the molecular ion. This motional excitation can be detected on the atomic ion. (
Credit: PTB

Nowadays atoms can be manipulated with lasers and their spectral features can be investigated with high precision e.g. in optical clocks. In these experiments state detection plays a crucial role: the fluorescence of an atom under illumination with laser light reveals its internal quantum state. 

Many atoms and most molecules, however, do not fluoresce at all. Therefore, one of the standard procedures for state detection in molecules exploited the fact that molecules can be broken apart with laser light of a certain frequency, depending on their quantum state. This lets one measure the quantum state of the molecule by destroying it. Of course this detection procedure can only be applied once per molecule.

Project leader Piet Schmidt has a long experience of systems in which state detection is difficult to achieve. He was involved in the development of 'quantum logic spectroscopy' in the research group of Nobel laureate David J. Wineland and extended it with his own research team to 'photon recoil spectroscopy'. 

Typical detection signal, where a quantum jump into the (J=1)-rotational state (from red to blue area) and a subsequent jump out of this state (blue to red) can be seen 
Credit: PTB

All of these novel spectroscopy techniques are based on a common principle: beside the ion under investigation, one traps a second ion of a different species that is controllable and whose fluorescence can be used for state detection. Because of their electrical repulsion, both particles behave as if they were connected by a strong spring, such that their motion is synchronized. 

This is how the measurement of one particle can reveal properties of the other particle. Schmidt and his colleagues use a molecular MgH+-ion (which is the subject of the investigation) and an atomic Mg+-ion (on which the measurements will be performed). They hold both particles with electric fields in an ion trap. Then, lasers are used to cool the particles' motion to the ground state, where the synchronous motion almost comes to rest.

The new trick demonstrated in this experiment relies on an additional laser, whose action is similar to an optical tweezer. It can be used to exert forces on the molecule. "The laser shakes the molecule only if the molecule is in one particular rotational state" explains Fabian Wolf, physicist in Schmidt's research group "We can detect the effect¬ -which is an excitation of the common motion of the molecule and the atom- on the atomic ion by using additional lasers. If the atom lights up, the molecule was in the state we probed. If it stays dark, the molecule was in some other state."

Piet Schmidt highlights two main results of the team's findings: "Because of the non-destructive nature of our technique, we could observe the molecule jumping from one rotational state to the other. It is the first time such quantum jumps have been observed directly in an isolated molecule. Moreover, we could improve on the uncertainty of a transition frequency to an electronically excited state". He also points towards future goals: "The next step is the systematic preparation of the molecule in that quantum state instead of waiting for the thermal radiation to randomly prepare it."

The researchers feel confident that their development will be important for the scientific communities that need precise methods for spectroscopy, e.g. quantum chemistry, where the inner structure of molecules is investigated, or astronomy, where spectra of cold molecules can teach us new things about the origin and the properties of the universe. Furthermore, precision molecular spectroscopy is important for the search for a variation of the fundamental constants and so far hidden properties of fundamental particles, such as the electric dipole moment of the electron.

These tests of fundamental physics were Schmidt's original motivation for working on the novel detection technique."To make these applications practical, we have to push molecular spectroscopy to a level similar to that of today's optical clocks based on atoms", says Piet Schmidt, when he gets asked for his long term goal, "For this purpose we have to improve our measurement resolution by orders of magnitude, which for sure will take several years".





Contacts and sources:
Prof. Dr. Piet O. Schmidt
QUEST-Institute at the Physikalisch-Technische Bundesanstalt (PTB)


Citation: F. Wolf, Y. Wan, J.C. Heip, F. Gebert, C. Shi, P.O. Schmidt: Non-destructive state detection for quantum logic spectroscopy of molecular ions. Nature (2016), DOI: 10.1038/nature16513





Great Attractor Pulling Milky Way and Hundreds of Hidden Galaxies Towards Itself

Hundreds of hidden nearby galaxies have been studied for the first time, shedding light on a mysterious gravitational anomaly dubbed the Great Attractor.

Despite being just 250 million light years from Earth—very close in astronomical terms—the new galaxies had been hidden from view until now by our own galaxy, the Milky Way.

Using CSIRO’s Parkes radio telescope equipped with an innovative receiver, an international team of scientists were able to see through the stars and dust of the Milky Way, into a previously unexplored region of space.

An annotated animation showing the location of the galaxies discovered in the 'Zone of Avoidance'. Until now this region of space has remained hidden from view because of the gas and dust of the Milky Way which blocks light at optical wavelengths from reaching telescopes on Earth. By using CSIRO's Parkes radio telescope to detect radio waves that can travel through our galaxy's gas and dust, hundreds of new galaxies have been found in the region of space known to astronomers as the 'Zone of Avoidance'. This animation has been created using the actual positional data of the new galaxies and randomly populating the region with galaxies of different sizes, types and colors.
Credit: ICRAR. Music by Holly Broadbent.

The discovery may help to explain the Great Attractor region, which appears to be drawing the Milky Way and hundreds of thousands of other galaxies towards it with a gravitational force equivalent to a million billion Suns.

Lead author Professor Lister Staveley-Smith, from The University of Western Australia node of the International Centre for Radio Astronomy Research (ICRAR), said the team found 883 galaxies, a third of which had never been seen before.

“The Milky Way is very beautiful of course and it’s very interesting to study our own galaxy but it completely blocks out the view of the more distant galaxies behind it,” he said.

An annotated artist's impression showing radio waves travelling from the new galaxies, then passing through the Milky Way and arriving at the Parkes radio telescope on Earth (not to scale). 
Credit: ICRAR

Professor Staveley-Smith said scientists have been trying to get to the bottom of the mysterious Great Attractor since major deviations from universal expansion were first discovered in the 1970s and 1980s.

“We don’t actually understand what’s causing this gravitational acceleration on the Milky Way or where it’s coming from,” he said.

“We know that in this region there are a few very large collections of galaxies we call clusters or superclusters, and our whole Milky Way is moving towards them at more than two million kilometres per hour.”

The research identified several new structures that could help to explain the movement of the Milky Way, including three galaxy concentrations (named NW1, NW2 and NW3) and two new clusters (named CW1 and CW2).

University of Cape Town astronomer Professor Renée Kraan-Korteweg said astronomers have been trying to map the galaxy distribution hidden behind the Milky Way for decades.

“We’ve used a range of techniques but only radio observations have really succeeded in allowing us to see through the thickest foreground layer of dust and stars,” she said.

“An average galaxy contains 100 billion stars, so finding hundreds of new galaxies hidden behind the Milky Way points to a lot of mass we didn't know about until now.”

A visualisation showing the coordinates of the new 'hidden galaxies'. At the centre is Earth. Blue represents galaxies found in other surveys and other colours show the locations of the new galaxies. 
Credit: ICRAR

Dr. Bärbel Koribalski from CSIRO Astronomy and Space Science said innovative technologies on the Parkes Radio telescope had made it possible to survey large areas of the sky very quickly.

“With the 21-cm multibeam receiver on Parkes we’re able to map the sky 13 times faster than we could before and make new discoveries at a much greater rate,” she said.

The study involved researchers from Australia, South Africa, the US and the Netherlands, and was published today in the Astronomical Journal.

An artist’s impression of the galaxies found in the ‘Zone of Avoidance’ behind the Milky Way. This scene has been created using the actual positional data of the new galaxies and randomly populating the region with galaxies of different sizes, types and colors.
 Credit: ICRAR

An animation showing the location of the galaxies discovered in the 'Zone of Avoidance'. Until now this region of space has remained hidden from view because of the gas and dust of the Milky Way which blocks light at optical wavelengths from reaching telescopes on Earth. By using CSIRO's Parkes radio telescope to detect radio waves that can travel through our galaxy's gas and dust, hundreds of new galaxies have been found in the region of space known to astronomers as the 'Zone of Avoidance'. This animation has been created using the actual positional data of the new galaxies and randomly populating the region with galaxies of different sizes, types and colours. 
Credit: ICRAR. Music by Holly Broadbent.

The International Centre for Radio Astronomy Research (ICRAR) is a joint venture between Curtin University and The University of Western Australia with support and funding from the State Government of Western Australia.

Professor Lister Staveley-Smith is ICRAR’s Director of Science at UWA and the Deputy Director of the ARC Centre of Excellence for All-sky Astrophysics (CAASTRO).

Dr Bärbel S. Koribalski is a CSIRO Science Leader, leading the HI group at CSIRO Astronomy and Space Science. Dr Koribalski and Prof Staveley-Smith are the principal investigators of WALLABY, the ASKAP HI All-Sky Survey.

The ‘Great Attractor’ is a diffuse concentration of mass 250 million light-years away, that’s pulling our galaxy, the Milky Way, and hundreds of thousands of other galaxies towards it.

CSIRO’s Parkes telescope, or “the Dish”, is a 64-metre radio telescope located in New South Wales, Australia. The telescope has been in operation since 1961 and continues to be at the forefront of astronomical discovery.




Contacts and sources:
Prof. Lister Staveley-Smith, University of Western Australia, ICRAR, CAASTRO
Prof. Renée C. Kraan-Korteweg, University of Cape Town
Dr Bärbel Koribalski, CSIRO Astronomy and Space Science
Pete Wheeler, Media Contact, ICRAR


Citation:
‘The Parkes HI Zone of Avoidance Survey’, published in the Astronomical Journal February 9th, 2016. Available at this link.

Earth-Like Planets Have Earth-Like Interiors


Every school kid learns the basic structure of the Earth: a thin outer crust, a thick mantle, and a Mars-sized core. But is this structure universal? Will rocky exoplanets orbiting other stars have the same three layers? New research suggests that the answer is yes - they will have interiors very similar to Earth.

"We wanted to see how Earth-like these rocky planets are. It turns out they are very Earth-like," says lead author Li Zeng of the Harvard-Smithsonian Center for Astrophysics (CfA).

To reach this conclusion Zeng and his co-authors applied a computer model known as the Preliminary Reference Earth Model (PREM), which is the standard model for Earth's interior. They adjusted it to accommodate different masses and compositions, and applied it to six known rocky exoplanets with well-measured masses and physical sizes.

This artist's illustration compares the interior structures of Earth (left) with the exoplanet Kepler-93b (right), which is one and a half times the size of Earth and 4 times as massive. New research finds that rocky worlds share similar structures, with a core containing about a third of the planet's mass, surrounded by a mantle and topped by a thin crust.

Credit: M. Weiss/CfA

They found that the other planets, despite their differences from Earth, all should have a nickel/iron core containing about 30 percent of the planet's mass. In comparison, about a third of the Earth's mass is in its core. The remainder of each planet would be mantle and crust, just as with Earth.

"We've only understood the Earth's structure for the past hundred years. Now we can calculate the structures of planets orbiting other stars, even though we can't visit them," adds Zeng.

The new code also can be applied to smaller, icier worlds like the moons and dwarf planets in the outer solar system. For example, by plugging in the mass and size of Pluto, the team finds that Pluto is about one-third ice (mostly water ice but also ammonia and methane ices).

The model assumes that distant exoplanets have chemical compositions similar to Earth. This is reasonable based on the relevant abundances of key chemical elements like iron, magnesium, silicon, and oxygen in nearby systems. However, planets forming in more or less metal-rich regions of the galaxy could show different interior structures. The team expects to explore these questions in future research.



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

Mysterious Menominee Crack Is Unusual Geological Pop-Up Feature

Seismologists studying a massive crack in the ground that appeared north of Menominee, Michigan in 2010 now think they know what the unusual feature might be. But as they explain in their study published this week in the journal Seismological Research Letters, there are still some mysteries to clear up about the strange geological occurrence in the rural Michigan woods.

A photo taken in 2010 of the Menominee Crack, a 'pop-up' geological feature.
Credit: Wayne Pennington/ Michigan Technological University

A team of scientists led by Wayne Pennington of Michigan Technological University says that the crack, which lies along the crest of a two-meter-high ridge that appeared at the same time, is probably a "pop-up" feature. Pop-ups occur in places where shallowly-buried rock layers spring upward after having been weighed down by rock or ice. Pop-ups--sometimes called "A-tents" for their shape--may develop in places where the earth rebounds upward after an overlying glacier shrinks away, or when rock overburden is removed in a quarry.

However, the last glaciers retreated from Menominee 11,000 years ago--and there isn't any quarrying in the area.

"One of our reasons for publishing this was that in our search of the literature we could find no other mention of modern pop-ups that didn't occur at something like the base of a quarry, where people had removed massive amounts of rock earlier," Pennington explained. "As far as we can tell, this is a one-of-a-kind event."

Residents near Menominee heard a loud noise and shaking in the early morning of October 4, 2010, and soon discovered the crack when they went into the nearby woods to clean up the debris left from removing a big double-trunked white pine tree a few days earlier. The crack split the ground for 110 meters, and was as deep as 1.7 meters in some places. Tree trunks tilted at precarious angles on either side of the fracture.

Pennington went to visit the site on his way back home from a scientific conference, he recalled. He paced off some measurements in his dress shoes and collected some GPS data with his phone. "I was completely blown away by it, because it wasn't what I was expecting when I saw it," he recalled. "It wasn't like anything I had seen before."

Although the crack was the most dramatic feature, Pennington was intrigued by the new ridge underneath it. "I kept trying to think of ways that there could have been an uplift from a thrusting earthquake or something, but anything like that requires such a huge amount of displacement in order to produce that amount of crustal shortening, that nothing made sense."

He shared the photos and data with his colleagues, until Stanford University geophysicist Norm Sleep pointed out that the feature formed from a shallow-buried layer of limestone, and looked like a pop-up. "This made perfect sense to us," Pennington said, "except for what caused it. And that then became the puzzle."

The researchers needed to get a better look at the rock underneath the ridge to confirm that it was a pop-up, so they turned to a technique called seismic refraction. The technique measures the speed of seismic waves as they travel within layers of the earth, as determined at different distances from the seismic source. In this case, the seismologists used a sledgehammer to strike a large metal ball lying on the ground, and captured the resulting seismic waves.

In broken rock, the waves travel faster as they move parallel to cracks in the rock, and slower when they move perpendicular to the cracks and have to travel across the fractures. The scientists found a pattern of refraction speeds that seemed to be consistent with the intense bending and then fracturing of the brittle limestone of a pop-up feature.

But what caused the pop-up to...pop-up? Without the usual suspects in play, Pennington and his colleagues had to do a little detective work. The limestone in the area may have been stressed almost to the point of cracking when the last glaciers retreated, they say. The recent removal of the double-trunked pine, which may have weighed as much as 2000 kilograms--over two tons--could have been the final straw, allowing the rock to bend upward when that weight was removed.

"There's a 60% chance that this explanation we provide is the right one," Pennington noted. "But since we haven't seen this kind of thing elsewhere, and the tree is such a small effect, we wonder if there might be something else."

The seismologists studied aerial photos of the region to see how soil has been removed in the past 50 years from road work and a re-design of the area's drainage system. These changes might have channeled more rainwater below the surface, potentially weakening the rock as it froze and thawed, the scientists suggest.

Pennington said "no one should be losing sleep" over the strange feature, which technically counted as the first natural earthquake in Michigan's Upper Peninsula--measuring less than magnitude 1.

"It may be a one-of-a kind phenomenon," he said. "But if it happens again, we'll be all over it, trying to figure it out."



Contacts and sources:
Becky Ham
Seismological Society of America

Mindboggling Fossil Fish Found


An international team of scientists have discovered two new plankton-eating fossil fish species of the genus called Rhinconichthys (Rink-O-nik-thees) from the oceans of the Cretaceous Period, about 92 million years ago, when dinosaurs roamed the planet.

One of the authors of the study, Kenshu Shimada, a paleobiologist at DePaul University, said Rhinconichthys are exceptionally rare, known previously by only one species from England. But a new skull from North America, discovered in Colorado along with the re-examination of another skull from Japan have tripled the number of species in the genus with a greatly expanded geographical range. According to Shimada, who played a key role in the study, these species have been named R. purgatoirensis and R. uyenoi, respectively.

An international team of scientists have discovered two new plankton-eating fossil fish species, of the genus called Rhinconichthys, which lived 92 million years ago in the oceans of the Cretaceous Period.

Credit:  Robert Nicholls  


"I was in a team that named Rhinconichthys in 2010, which was based on a single species from England, but we had no idea back then that the genus was so diverse and so globally distributed," said Shimada.

The new study, "Highly specialized suspension-feeding bony fish Rhinconichthys (Actinopterygii: Pachycormiformes) from the mid-Cretaceous of the United States, England and Japan," will appear in the forthcoming issue of the international scientific journalCretaceous Research.

The research team includes scientists from government, museum, private sector and university careers. They include Bruce A. Schumacher from the United Sates Forest Service who discovered the new specimen. It also includes researchers, Jeff Liston from the National Museum of Scotland and Anthony Maltese from the Rocky Mountain Dinosaur Resource Center.

Rhinconichthys belongs to an extinct bony fish group called pachycormids, which contains the largest bony fish ever to have lived. The new study specifically focuses on highly elusive forms of this fish group that ate plankton.

Rhinconichthys was estimated to be more than 6.5 feet and fed on plankton. It had a pair of bones called hyomandibulae, which formed a massive oar-shaped lever to protrude and swing the jaws open extra wide, like a parachute, in order to receive more plankton-rich water into its mouth.
               
Credit: Kenshu Shimada

Rhinconichthys was estimated to be more than 6.5 feet and fed on plankton. It had a highly unusual specialization for bony fish. According to Shimada, one pair of bones called hyomandibulae formed a massive oar-shaped lever to protrude and swing the jaws open extra wide, like a parachute, in order to receive more plankton-rich water into its mouth, similar to the way many sharks open their mouth.

A planktivorous diet, also called suspension-feeding, is known among some specialized aquatic vertebrates today, including the Blue Whale, Manta Ray and Whale Shark. The name Rhinconichthys means a fish like the Whale Shark, Rhincodon. Suspension-feeding in the dinosaur era is a new emerging area of research.

"Based on our new study, we now have three different species of Rhinconichthys from three separate regions of the globe, each represented by a single skull," Shimada noted. "This tells just how little we still know about the biodiversity of organisms through the Earth's history. It's really mindboggling ."


Contacts and sources:  
Jon Cecero
DePaul University

Saturday, February 6, 2016

Man-Made Underwater Sound May Have Wider Ecosystem Effects Than Previously Thought

Underwater sound linked to human activity could alter the behavior of seabed creatures that play a vital role in marine ecosystems, according to new research from the University of Southampton.

The study, reported in the journal Scientific Reports published by Nature, found that exposure to sounds that resemble shipping traffic and offshore construction activities results in behavioral responses in certain invertebrate species that live in the marine sediment.

These species make a crucial contribution to the seabed ecosystem as their burrowing and bioirrigation activities (how much the organism moves water in and out of the sediment by its actions) are crucial in nutrient recycling and carbon storage.

Image shows a langoustine (Nephrops norvegicus)
Credit: University of Southampton

The study showed that some man-made sounds can cause certain species to reduce irrigation and sediment turnover. Such reductions can lead to the formation of compacted sediments that suffer reduced oxygen, potentially becoming anoxic (depleted of dissolved oxygen and a more severe condition of hypoxia), which may have an impact on seabed productivity, sediment biodiversity and also fisheries production.

Lead author Martin Solan, Professor in Marine Ecology, said: "Coastal and shelf environments support high levels of biodiversity that are vital in mediating ecosystem processes, but they are also subject to noise associated with increasing levels of offshore human activity. Previous work has almost exclusively focussed on direct physiological or behavioural responses in marine mammals and fish, and has not previously addressed the indirect impacts of sound on ecosystem properties.

"Our study provides evidence that exposing coastal environments to anthropogenic sound fields is likely to have much wider ecosystem consequences than are presently understood."

The Southampton researchers exposed three species - the langoustine (Nephrops norvegicus), a slim, orange-pink lobster which grows up to 25 cm long, the Manila clam (Ruditapes philippinarum) and the brittlestar Amphiura filfiformis - to two different types of underwater sound fields: continuous broadband noise (CBN) that mimics shipping traffic and intermittent broadband noise (IBN) reflecting marine construction activity.

The sounds were reproduced in controlled test tanks and experiments were run on one species at a time. For CBN, a recording (one minute duration, continuously looped) of a ship made in the English Channel at a distance of around 100 metres was used'. For IBN, a recording (two minutes duration, continuously looped) of a wind farm in the North Sea at a distance of about 60 metres was used.

The results showed that the sounds could alter the way these species behaved when interacting with their environments.

With the langoustine, which disturbs the sediment to create burrows in which it lives, the researchers saw a reduction in the depth of sediment redistribution (how much of the surface sediment was overturned into the deeper layers) with exposure to IBN or CBN. Under CBN and IBN there was evidence that bioirrigation increased.

The Manila clam, a commercial fishery species in Europe that lives in the sediment and connects to the overlying water through a retractable siphon, reduced its surface activity under CBN, which affected the surface roughness of the sediment. Bioirrigation, which is strongly influenced by clam behaviour and the activity of the siphon, was markedly reduced by CBN and slightly reduced under IBN.

However, the sound fields had little impact on the brittlestar.

Co-author Dr Chris Hauton, Associate Professor in Invertebrate Ecophysiology and Immune Function, said: "I think these findings raise the prospect that anthropogenic sounds in the marine environment are impacting marine invertebrate species in ways that have not been previously anticipated. The potential effects of anthropogenic noise on ecosystem function, mediated through changes in organism behaviour merits further study as, in the long term, it may identify impacts to the productivity of seabed systems that have, to date, not really been constrained."

Tim Leighton, Professor of Ultrasonics and Underwater Acoustics and study co-author, added: "There has been much discussion over the last decade of the extent to which whales, dolphins and fish stocks, might be disturbed by the sounds from shipping, windfarms and their construction, seismic exploration etc. However, one set of ocean denizens has until now been ignored, and unlike these other classes, they cannot easily move away from loud man-made sound sources. These are the bottom feeders, such as crabs, shellfish and invertebrates similar to the ones in our study, which are crucial to healthy and commercially successful oceans because they form the bottom of the food chain."


Contacts and sources:

Land Degradation Affects 3.2 Billion People

Land degradation is on the rise to a dramatic extent, affecting around 3.2 billion people worldwide. Every dollar invested in saving land and soils today will save us five dollars in the future. Professor Klaus Töpfer, former Executive Director of UNEP; Professor Joachim von Braun, Director of the Center for Development Research, University of Bonn (ZEF); and Dr. Stefan Schmitz, German Federal Ministry for Economic Cooperation and Development (BMZ) will present the latest research insights on this issue.


Credit:  United Nations

The press conference will be held on Thursday, February 11, 2016, 10:00 AM – 11:00 AM in the Berlin-Brandenburgische Akademie der Wissenschaften, Jägerstraße 22/23, in 10117 Berlin.

Land and soil are the basis of life on Earth. Nevertheless, insufficient effort has been made so far to ensure sustainable land use and the protection of soils. This is the conclusion that a team of international scientists has drawn from studies conducted in 12 world regions and countries, including India, Argentina, Central Asia, Russia and a large number of African countries. 

The findings, partly based on remote-sensing satellite data, are alarming: Globally, 33 percent of grasslands, 25 percent of croplands and 23 percent of forests have experienced degradation over the past three decades. Around 30 percent of the global land area, home to around 3.2 billion people, is affected by significant soil degradation. The global costs amount to around 300 billion Euros per annum. The global assessment concludes: Every US Dollar invested today will save us five US Dollars in the future.

“Sustainable land management contributes to achieving several of the Sustainable Development Goals (SDGs), such as land degradation neutrality and an ambitious climate and biodiversity agenda. This fact was highlighted in the series of Global Soil Week events held in Berlin in recent years”, explains Professor Klaus Töpfer, former Executive Director the United Nations Environment Programme (UNEP).

“Soil is the most neglected natural resource”, states Professor Joachim von Braun, Director of the Center for Development Research (ZEF) and co-editor of the book “Economics of Land Degradation and Improvement – A Global Assessment for Sustainable Development”, which was published by Springer recently. “Yet, investments in land and soil are crucial for food supply, climate and human security”, von Braun adds.

According to von Braun: “The international scientists involved in these country case studies basically all reach the same conclusion; namely, that if we invest in rescuing global land and soil now, the cost will be much lower than if we wait longer. This applies both to industrialized and developing countries alike”.

The high levels of land degradation in croplands and grazing lands in developing countries, especially in sub-Saharan Africa, pose a serious problem too and may lead to migration. Often, there is a lack of advisory services and knowledge transfer for farmers, for example about integrated soil fertility management. Poor access to markets is another obstacle as well as weak security of land tenure.

The latter means that farmers are not motivated to practice sustainable land use methods. “In order to change this, the German government has been substantially involved in sustainable land use initiatives”, emphasizes Stefan Schmitz of the German Federal Ministry for Economic Cooperation and Development (BMZ), who is the coordinator of the BMZ special initiative ‘One World no Hunger’. “Combating land degradation is one of the most important elements in our fight against hunger”, he adds.


Contacts and sources:
Universität Bonn

Global Sea Levels Could Rise 3 Meters Due to Melting Antarctic Ice

Loss of ice in Antarctica caused by a warming ocean could raise global sea levels by three meters, research by Northumbria and Edinburgh universities suggests.

Scientists carrying out fieldwork in the region have assessed the landscape to determine how the West Antarctic ice sheet might respond to increasing global temperatures.

In the first study of its kind, researchers were able to gauge how levels of ice covering the land have changed over hundreds of thousands of years. They did so by studying peaks protruding through ice in the Ellsworth Mountains, on the Atlantic flank of Antarctica.

Credit: Northumbria University

The team assessed changes on slopes at various heights on the mountainside, which indicate levels previously reached by the ice sheet. They also mapped the distribution of boulders on the mountainside, which were deposited by melting glaciers. Chemical technology – known as exposure dating – showed how long rocks had been exposed to the atmosphere, and their age.

Their results indicate that during previous warm periods, a substantial amount of ice would have been lost from the West Antarctic ice sheet by ocean melting, but it would not have melted entirely. This suggests that ice would have been lost from areas below sea level, but not on upland areas. The research shows that parts of the West Antarctic ice sheet have existed continuously for at least 1.4 million years.

The study, published in Nature Communications, was carried out by researchers at Northumbria University and the University of Edinburgh, alongside the Scottish Universities Environmental Research Centre. It was supported by the Natural Environment Research Council and the British Antarctic Survey.

Credit: Northumbria University

Professor John Woodward, Northumbria’s Associate Dean (Research and Innovation) in Engineering and Environment, co-led the study.

He said: “It is possible that the ice sheet has passed the point of no return and, if so, the big question is how much will go and how much will sea levels rise.”

Dr Andrew Hein, of the University of Edinburgh’s School of GeoSciences, joint leader of the study, added: “Our findings narrow the margin of uncertainty around the likely impact of the West Antarctic Ice Sheet on sea level rise. This remains a troubling forecast since all signs suggest the ice from West Antarctica could disappear relatively quickly.”

Cold and paleo environments are one of Northumbria’s research specialisms in the Department of Geography. Research involves field based projects in cold regions across the globe, including Antarctica, a range of high Arctic European and Canadian sites, New Zealand, the Alps, Alaska and Chile.

The group applies novel techniques to field data collection, including ground-penetrating radar, new borehole radar technologies, seismics, NIR camera techniques, meteorological monitoring technologies, the use of unmanned aerial vehicles (UAV) and terrestrial laser scanning (TLS), to address fundamental questions in Earth Systems Science. Cutting-edge physical and numerical modelling, remote sensing and laboratory techniques for palaeo-environmental work are also applied.


Contacts and sources:
Northumbria University

Turbulent Times: When Stars Approach

HITS astrophysicists are using new methods to simulate the common-envelope phase of binary stars and discovering dynamic irregularities that may help to explain how supernovae evolve.

When we look at the night sky, we see stars as tiny points of light eking out a solitary existence at immense distances from Earth. But appearances are deceptive. More than half the stars we know of have a companion, a second nearby star that can have a major impact on their primary companions. 

The interplay within these so-called binary star systems is particularly intensive when the two stars involved are going through a phase in which they are surrounded by a common envelope consisting of hydrogen and helium. Compared to the overall time taken by stars to evolve, this phase is extremely short, so astronomers have great difficulty observing and hence understanding it. This is where theoretical models with highly compute-intensive simulations come in. Research into this phenomenon is relevant understanding a number of stellar events such as supernovae.

The simulation video visualizes the evolution of the density during a time span of 105 days. As the core of the red giant and the companion draw closer together, the gravity between them releases energy that passes into the common envelope. The turbulent instabilities that occur during this phase become clearly evident. (\
Video: Sebastian Ohlmann / HITS

Using new methods, astrophysicists Sebastian Ohlmann, Friedrich Roepke, Ruediger Pakmor, and Volker Springel of the Heidelberg Institute for Theoretical Studies (HITS) have now made a step forward in modeling this phenomenon. As they report in The Astrophysical Journal Letters, the scientists have successfully used simulations to discover dynamic irregularities that occur during the common-envelope phase and are crucial for the subsequent existence of binary star systems. These so-called instabilities change the flow of matter inside the envelope, thus influencing the stars' distance from one another and determining, for example, whether a supernova will ensue and, if so, what kind it will be.

This image shows a slice through the three-dimensional simulation volume after 105 days in the common envelope. In the orbital plane (figure 1), the companion star and the red giant core are circling around each other. 
Image: Sebastian Ohlmann / HITS

The article is the fruit of collaboration between two HITS research groups, the Physics of Stellar Objects (PSO) group and the Theoretical Astrophysics group (TAP). Prof. Volker Springel's Arepo code for hydrodynamic simulations was used and adapted for the modeling. It solves the equations on a moving mesh that follows the mass flow, and thus enhances the accuracy of the model.

Two stars, one envelope

More than half the stars we know of have evolved in binary star systems. The energy for their luminosity comes from the nuclear fusion of hydrogen at the core of the stars. As soon as the hydrogen fueling the nuclear fusion is exhausted in the heavier of the two stars, the star core shrinks. At the same time, a highly extended stellar envelope evolves, consisting of hydrogen and helium. The star becomes a red giant.

As the envelope of the red giant goes on expanding, the companion star draws the envelope to itself via gravity, and part of the envelope flows towards it. In the course of this process the two stars come closer to one another. Finally, the companion star may fall into the envelope of the red giant and both stars are then surrounded by a common envelope. 

As the core of the red giant and the companion draw closer together, the gravity between them releases energy that passes into the common envelope. As a result, the envelope is ejected and mixes with interstellar matter in the galaxy, leaving behind it a close binary star system consisting of the core of the giant and the companion star.

The path to stellar explosion

Sebastian Ohlmann of the PSO group explains why this common-envelope phase is important for our understanding of the way various star systems evolve: "Depending on what the system of the common envelope looks like initially, very different phenomena may ensue in the aftermath, such as thermonuclear supernovae." 

Figure 2 shows a plane perpendicular to the orbital plane.

Image: Sebastian Ohlmann / HITS

Ohlmann and colleagues are investigating the run-up to these stellar explosions, which are among the most luminous events in the universe and can light up a whole galaxy. But modeling the systems that can lead to such explosions is bedeviled by major uncertainty in the description of the common-envelope phase. 

One of the reasons for this is that the core of the giant is anything between a thousand and ten thousand times smaller than the envelope, so that spatial and temporal scale differences complicate the modeling process and make approximations necessary. The methodically innovative simulations performed by the Heidelberg scientists are a first step towards a better understanding of this phase.



Contacts and sources:
Dr. Peter Saueressig
HITS Heidelberg Institute for Theoretical Studies


Citation: Ohlmann, S. T., Roepke, F. K., Pakmor, R., & Springel, V. (2016): Hydrodynamic moving-mesh simulations of the common envelope phase in binary stellar systems, The Astrophysical Journal Letters, 816, L9, DOI: 10.3847/2041-8205/816/1/L9
http://arxiv.org/abs/1512.04529
Astrophysics Data System: http://adsabs.harvard.edu/abs/2016ApJ...816L...9O

'Cannibalism' Between Stars: New Research Shows the Turbulent Past of Our Sun


Stars are born inside a rotating cloud of interstellar gas and dust, which contracts to stellar densities thanks to its own gravity. Before finding itself on the star, however, most of the cloud lands onto a circumstellar disk forming around the star owing to conservation of angular momentum. The manner in which the material is transported through the disk onto the star, causing the star to grow in mass, has recently become a major research topic in astrophysics.

This is a Simulation of a gravitationally unstable circumstellar disk by means of hydrodynamic calculations. Protoplanetary 'embryo' form in the disc thanks to gravitational fragmentation. The three small pictures show the successive 'disappearance' of the lump by the star.

Credit: Copyright: Eduard Vorobyov, Universität Wien

It turned out that stars may not accumulate their final mass steadily, as was previously thought, but in a series of violent events manifesting themselves as sharp stellar brightening. The young FU Orionis star in the constellation of Orion is the prototype example, which showed an increase in brightness by a factor of 250 over a time period of just one year, staying in this high-luminosity state now for almost a century.

One possible mechanism that can explain these brightening events was put forward 10 years ago by Eduard Vorobyov, now working at the Astrophysical Department of the Vienna University, in collaboration with Shantanu Basu from the University of Western Ontario, Canada.

According to their theory, stellar brightening can be caused by fragmentation due to gravitational instabilities in massive gaseous disks surrounding young stars, followed by migration of dense gaseous clumps onto the star. Like the process of throwing logs into a fireplace, these episodes of clump consumption release excess energy which causes the young star to brighten by a factor of hundreds to thousands. During each episode, the star is consuming the equivalent of one Earth mass every ten days. After this, it may take another several thousand years before another event occurs.

Eduard Vorobyov describes the process of clump formation in circumstellar disks followed by their migration onto the star as "cannibalism on astronomical scales". These clumps could have matured into giant planets such as Jupiter, but instead they were swallowed by the parental star. This invokes an interesting analogy with the Greek mythology, wherein Cronus, the leader of the first generation of Titans, ate up his newborn children (though failing to gobble up Zeus, who finally brought death upon his father).

These are the polarized intensities of four selected FU Orionis objects observed with the 8.2-meter Subaru Telescope. Significant asymmetries, such as elbows, arms and broad trends -- typical of gravitationally unstable disks -- are indicated by arrows.

Credit:  Copyright: Eduard Vorobyov, Universität Wien

With the advent of advanced observational instruments, such as SUBARU 8.2 meter optical-infrared telescope installed in Mauna Kea (Hawaii), it has become possible for the first time to test the model predictions. Using high-resolution, adaptive optics observations in the polarized light, an international group of astronomers led by Hauyu Liu from European Space Observatory (Garching, Germany) has verified the presence of the key features associated with the disk fragmentation model -- large-scale arms and arcs surrounding four young stars undergoing luminous outbursts, including the prototype FU Orionis star itself. The results of this study were accepted for publication in Science Advances - a peer-review, open-access journal belonging to the Science publishing group.

"This is a major step towards our understanding of how stars and planets form and evolve", says Vorobyov, "If we can prove that most stars undergo such episodes of brightening caused by disk gravitational instability, this would mean that our own Sun might have experienced several such episodes, implying that the giant planets of the Solar system may in fact be lucky survivors of the Sun's tempestuous past".




Contacts and sources: 
Eduard Vorobyov
Vienna University

Citation:  Hauyu Baobab Liu, Michihiro Takami, Tomoyuki Kudo, Jun Hashimoto, Ruobing Dong, Eduard I. Vorobyov, Tae-Soo Pyo, Misato Fukagawa, Motohide Tamura, Thomas Henning, Michael M. Dunham, Jennifer Karr, Nobuhiko Kusakabe, Toru Tsuribe: "Circumstellar Disks of the Most Vigorously Accreting Young Stars", published online February 5, 2016. Publication in Science Advances  

Thursday, February 4, 2016

Changing Weather Patterns Making Southwest Drier; Less Rain The New Normal

The weather patterns that typically bring moisture to the southwestern United States are becoming more rare, an indication that the region is sliding into the drier climate state predicted by global models, according to a new study.

“A normal year in the Southwest is now drier than it once was,” said Andreas Prein, a postdoctoral researcher at the National Center for Atmospheric Research (NCAR) who led the study. “If you have a drought nowadays, it will be more severe because our base state is drier.”

Weather systems that typically bring moisture to the southwestern United States are forming less often, resulting in a drier climate across the region. This map depicts the portion of overall changes in precipitation across the United States that can be attributed to these changes in weather system frequency. The gray dots represent areas where the results are statistically significant.

Credit: Andreas Prein, NCAR.

Climate models generally agree that human-caused climate change will push the southwestern United States to become drier. And in recent years, the region has been stricken by drought. But linking model predictions to changes on the ground is challenging.

In the new study—published online today in the journal Geophysical Research Letters, a publication of the American Geophysical Union—NCAR researchers grapple with the root cause of current drying in the Southwest to better understand how it might be connected to a warming climate.

Subtle shift yields dramatic impact

For the study, the researchers analyzed 35 years of data to identify common weather patterns—arrangements of high and low pressure systems that determine where it’s likely to be sunny and clear or cloudy and wet, among other things. They identified a dozen patterns that are typical for the weather activity in the contiguous United States and then looked to see whether those patterns were becoming more or less frequent.

“The weather types that are becoming more rare are the ones that bring a lot of rain to the southwestern United States,” Prein said. “Because only a few weather patterns bring precipitation to the Southwest, those changes have a dramatic impact.”

The Southwest is especially vulnerable to any additional drying. The region, already the most arid in the country, is home to a quickly growing population that is putting tremendous stress on its limited water resources.

“Prolonged drought has many adverse effects,” said Anjuli Bamzai, program director in the National Science Foundation’s Division of Atmospheric and Geospace Sciences, which funded the research, “so understanding regional precipitation trends is vital for the well-being of society. These researchers demonstrate that subtle shifts in large-scale weather patterns over the past three decades or so have been the dominant factor in precipitation trends in the southwestern United States.”

The study also found an opposite, though smaller, effect in the Northeast, where some of the weather patterns that typically bring moisture to the region are increasing.

“Understanding how changing weather pattern frequencies may impact total precipitation across the U.S. is particularly relevant to water resource managers as they contend with issues such as droughts and floods, and plan future infrastructure to store and disperse water,” said NCAR scientist Mari Tye, a co-author of the study.

The climate connection

The three patterns that tend to bring the most wet weather to the Southwest all involve low pressure centered in the North Pacific just off the coast of Washington, typically during the winter. Between 1979 and 2014, such low-pressure systems formed less and less often. The associated persistent high pressure in that area over recent years is a main driver of the devastating California drought.

This shift toward higher pressure in the North Pacific is consistent with climate model runs, which predict that a belt of higher average pressure that now sits closer to the equator will move north. This high-pressure belt is created as air that rises over the equator moves poleward and then descends back toward the surface. The sinking air causes generally drier conditions over the region and inhibits the development of rain-producing systems.

Many of the world’s deserts, including the Sahara, are found in such regions of sinking air, which typically lie around 30 degrees latitude on either side of the equator. Climate models project that these zones will move further poleward. The result is a generally drier Southwest.

While climate change is a plausible explanation for the change in frequency, the authors caution that the study does not prove a connection. To examine this potential connection further, they are studying climate model data for evidence of similar changes in future weather pattern frequencies.

“As temperatures increase, the ground becomes drier and the transition into drought happens more rapidly,” said NCAR scientist Greg Holland, a co-author of the study. “In the Southwest the decreased frequency of rainfall events has further extended the period and intensity of these droughts.”


Contacts and sources: 
Nanci Bompey
The American Geophysical Union

Bright Sparks Shed New Light On the Dark Matter Riddle

The origin of matter in the universe has puzzled physicists for generations. Today, we know that matter only accounts for 5% of our universe; another 25% is constituted of dark matter. And the remaining 70% is made up of dark energy. Dark matter itself represents an unsolved riddle.


Physicists believe that such dark matter is composed of (as yet undefined) elementary particles that stick together thanks to gravitational force. In a study recently published in EPJ C, scientists from the CRESST-II research project use the so-called phonon-light technique to detect dark matter. They are the first to use a detection probe that operates with such a low trigger threshold, which yields suitable sensitivity levels to uncover the as-yet elusive particles responsible for dark matter.

Until quite recently, the so-called WIMP - Weakly Interacting Massive Particle - was the preferred candidate for a new elementary particle to explain dark matter. However, the asymmetric dark matter particle models have attracted more and more interest in the past few years. The experimental detection is no different from the scattering of two billiard balls, as the particle scatters on an atomic nucleus. The detection method is based on the fact that the scattering would heat up a calcium tungstate (CaWO4) crystal.

The challenge: the lighter the dark matter particle is, the smaller the energy deposited in the crystal is. Currently, no other direct dark matter search method has a threshold for nuclear recoils as low as 0.3 kiloelectronVolt (keV). As such, the CRESST-II team are the first to ever probe dark matter particle masses at such low mass scale (below one GeV/c^2-as far as 0.5GeV/c^2). The next-generation CRESST-III detector is currently being upgraded and promises to reach thresholds of 100 electronVolts (eV), following successful tests of prototypes.



Contacts and sources:
Sabine Lehr
Springer

Good or Bad? Deodorants and Antiperspirants Alter the Microbial Ecosystem on Your Skin

Wearing antiperspirant or deodorant doesn’t just affect your social life, it substantially changes the microbial life that lives on you. New research finds that antiperspirant and deodorant can significantly influence both the type and quantity of bacterial life found in the human armpit’s “microbiome.” The work was done by researchers at North Carolina State University, the North Carolina Museum of Natural Sciences, North Carolina Central University, Rutgers University and Duke University.

“We wanted to understand what effect antiperspirant and deodorant have on the microbial life that lives on our bodies, and how our daily habits influence the life that lives on us,” says Julie Horvath, head of the genomics and microbiology research laboratory at the NC Museum of Natural Sciences, an associate research professor at NC Central, and corresponding author of a paper describing the work published in the journal PeerJ. “Ultimately, we want to know if any changes in our microbial ecosystem are good or bad, but first we have to know what the landscape looks like and how our daily habits change it.”

Cultured bacteria from one of the samples in the study. 
Photo credit: Dawn Stancil, North Carolina Central University.

“Thousands of bacteria species have the potential to live on human skin, and in particular in the armpit,” says Rob Dunn, a professor of applied ecology at NC State and co-author of the paper. “Just which of these species live in any particular armpit has been hard to predict until now, but we’ve discovered that one of the biggest determinants of the bacteria in your armpits is your use of deodorant and/or antiperspirant.”

“Within the last century, use of underarm products has become routine for the vast majority of Americans,” says Julie Urban, co-author of the paper, assistant head of the genomics and microbiology laboratory at the NC Museum of Natural Sciences, and adjunct professor of entomology at NC State. “Yet, whether use of these products favors certain bacterial species – be they pathogenic or perhaps even beneficial – seems not to have been considered, and remains an intriguing area needing further study.”

Chart detailing differences in microbial diversity among study participants.  
Credit:  North Carolina State University

To learn about the microbial impact of antiperspirant and deodorant, the researchers recruited 17 study participants: three men and four women who used antiperspirant products, which reduce the amount we sweat; three men and two women who used deodorant, which often includes ethanol or other antimicrobials to kill off odor-causing microbes; and three men and two women who used neither product. They then launched an eight-day experiment, in which all of the participants had swabs taken of their armpits between 11 a.m. and 1 p.m.

On day one, participants followed their normal hygiene routine in regard to deodorant or antiperspirant use. On days two through six, participants did not use any deodorant or antiperspirant. On days seven and eight, all participants used antiperspirant.

The researchers then cultured all the samples to determine the abundance of microbial organisms growing on each participant and how that differed day to day.

“We found that, on the first day, people using antiperspirant had fewer microbes in their samples than people who didn’t use product at all – but there was a lot of variability, making it hard to draw firm conclusions,” Horvath says. “In addition, people who used deodorant actually often had more microbes – on average – than those who didn’t use product.”

By the third day, participants who had used antiperspirant were beginning to see more microbial growth. And by day six, the amount of bacteria for all study participants was fairly comparable.

“However, once all participants began using antiperspirant on days seven and eight, we found very few microbes on any of the participants, verifying that these products dramatically reduce microbial growth,” Horvath notes.

The researchers also did genetic sequencing on all of the samples from days three and six, to determine how antiperspirant and deodorant might affect the microbial biodiversity – the composition and variety of types of bacteria – over time.

They found that, among study participants who hadn’t worn deodorant or antiperspirant, 62 percent of the microbes they found were Corynebacteria, followed by various Staphylococcaceae bacteria (21 percent), with a random assortment of other bacteria accounting for less than 10 percent. Corynebacteria are partially responsible for producing the bad smells we associate with body odor, but they are also thought to help us defend against pathogens. Staphylococcaceae are a diverse group of bacteria that are among the most common microbes found on human skin and, while some can pose a risk to human health, most are considered beneficial.

The participants who had been regular antiperspirant users coming into the study had wildly different results. Sixty percent of their microbes were Staphylococcaceae, only 14 percent were Corynebacteria, and more than 20 percent were filed under “other” – meaning they were a grab-bag of opportunistic bacteria.

“Using antiperspirant and deodorant completely rearranges the microbial ecosystem of your skin – what’s living on us and in what amounts,” Horvath says. “And we have no idea what effect, if any, that has on our skin and on our health. Is it beneficial? Is it detrimental? We really don’t know at this point. Those are questions that we’re potentially interested in exploring.”

The new findings also highlight how human behavior can have a profound, if unintended, impact on the evolution of microbial organisms.

In another paper, published last month in Proceedings of the Royal Society B, the researchers, in addition to collaborators at Duke and the University of Pennsylvania, examined the diversity and abundance of microbes found in the armpits of humans, compared to other primates: chimpanzees, gorillas, baboons and rhesus macaques. In that paper, the researchers found that armpit microbes have evolved over time in conjunction with the primates they live on. But the microbial ecosystems found in the armpits of humans are vastly different – and far less diverse – than those found in our primate relatives.

“One exciting finding was that the non-human primates were more covered in fecal and soil associated microbes, which we often view as dirty,” Horvath says. “Perhaps the diversity of fecal and soil microbes on non-human primate skin serves some benefit that we don’t yet understand or appreciate.

“Over evolutionary time, we would expect our microbes to co-evolve with us,” Horvath says. “But we appear to have altered that process considerably through our habits, from bathing to taking steps to change the way we look or smell.”

The PeerJ paper, “The effect of habitual and experimental antiperspirant and deodorant product use on the armpit microbiome,” is under embargo and will be published at 7 a.m. EST on Feb. 2. The paper was co-authored by Daniel Fergus, Amy Savage, Megan Ehlers and Holly Menninger.

The paper was supported by the National Science Foundation, under grants 0953390 and 1319293; the U.S. Army Research Office, under grant W911NF-14-1-0556; and the Howard Hughes Medical Institute, under grant 52006933.


Contacts and sources: 
Matt Shipman
North Carolina State University