Basic plasma wave physics reshaped by NASA observations

When NASA's Magnetospheric Multiscale -- or MMS -- mission was launched, the scientists knew it would answer questions fundamental to the nature of our universe -- and MMS hasn't disappointed. A new finding, presented in a paper in Nature Communications, provides observational proof of a 50-year-old theory and reshapes the basic understanding of a type of wave in space known as a kinetic Alfvén wave. The results, which reveal unexpected, small-scale complexities in the wave, are also applicable to nuclear fusion techniques, which rely on minimizing the existence of such waves inside the equipment to trap heat efficiently.

Kinetic Alfvén waves have long been suspected to be energy transporters in plasmas -- a fundamental state of matter composed of charged particles -- throughout the universe. But it wasn't until now, with the help of MMS, that scientists have been able to take a closer look at the microphysics of the waves on the relatively small scales where the energy transfer actually happens.

"This is the first time we've been able to see this energy transfer directly," said Dan Gershman, lead author and MMS scientist at NASA's Goddard Space Flight Center in Greenbelt, Maryland, and the University of Maryland in College Park. "We're seeing a more detailed picture of Alfvén waves than anyone's been able to get before."

The waves could be studied on a small scale for the first time because of the unique design of the MMS spacecraft. MMS's four spacecraft fly in a compact 3-D pyramid formation, with just four miles between them -- closer than ever achieved before and small enough to fit between two wave peaks. Having multiple spacecraft allowed the scientists to measure precise details about the wave, such as how fast it moved and in what direction it travelled.

Previous multi-spacecraft missions flew at much larger separations, which didn't allow them to see the small scales -- much like trying to measure the thickness of a piece of paper with a yardstick. MMS's tight flying formation, however, allowed the spacecraft to investigate the shorter wavelengths of kinetic Alfvén waves, instead of glossing over the small-scale effects.

"It's only at these small scales that the waves are able to transfer energy, which is why it's so important to study them," Gershman said.

As kinetic Alfvén waves move through a plasma, electrons traveling at the right speed get trapped in the weak spots of the wave's magnetic field. Because the field is stronger on either side of such spots, the electrons bounce back and forth as if bordered by two walls, in what is known as a magnetic mirror in the wave. As a result, the electrons aren't distributed evenly throughout: Some areas have a higher density of electrons, and other pockets are left with fewer electrons. Other electrons, which travel too fast or too slow to ride the wave, end up passing energy back and forth with the wave as they jockey to keep up.

The wave's ability to trap particles was predicted more than 50 years ago but hadn't been directly captured with such comprehensive measurements until now. The new results also showed a much higher rate of trapping than expected.

This method of trapping particles also has applications in nuclear fusion technology. Nuclear reactors use magnetic fields to confine plasma in order to extract energy. Current methods are highly inefficient as they require large amounts of energy to power the magnetic field and keep the plasma hot. The new results may offer a better understanding of one process that transports energy through a plasma.

"We can produce, with some effort, these waves in the laboratory to study, but the wave is much smaller than it is in space," said Stewart Prager, plasma scientist at the Princeton Plasma Physics Laboratory in Princeton, New Jersey. "In space, they can measure finer properties that are hard to measure in the laboratory."

This work may also teach us more about our sun. Some scientists think kinetic Alfvén waves are key to how the solar wind -- the constant outpouring of solar particles that sweeps out into space -- is heated to extreme temperatures. The new results provide insight on how that process might work.

Throughout the universe, kinetic Alfvén waves are ubiquitous across magnetic environments, and are even expected to be in the extra-galactic jets of quasars. By studying our near-Earth environment, NASA missions like MMS can make use of a unique, nearby laboratory to understand the physics of magnetic fields across the universe.

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Materials provided by NASA/Goddard Space Flight Center. Original written by Mara Johnson-Groh. Note: Content may be edited for style and length.

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Basic plasma wave physics reshaped by NASA observations

Discovery of a source of fast magnetic reconnection

Magnetic reconnection, a universal process that triggers solar flares and northern lights and can disrupt cell phone service and fusion experiments, occurs much faster than theory says that it should. Now researchers at the U.S. Department of Energy's (DOE) Princeton Plasma Physics Laboratory (PPPL) and Germany's Max Planck Institute of Plasma Physics have discovered a source of the speed-up in a common form of reconnection. Their findings could lead to more accurate predictions of damaging space weather and improved fusion experiments.

Reconnection occurs when the magnetic field lines in plasma -- the collection of atoms and charged electrons and atomic nuclei, or ions, that make up 99 percent of the visible universe -- converge and forcefully snap apart. Electrons that exert a varying degree of pressure form an important part of this process as reconnection takes place.

The research team found that variation in the electron pressure develops along the magnetic field lines in the region undergoing reconnection. This variation balances and keeps a strong electric current inside the plasma from growing out of control and halting the reconnection process. It is this balancing act that makes possible fast reconnection.

"The main issue we addressed is how reconnection can take place so quickly," said Will Fox, lead author of a paper that detailed the findings in March in the journal Physical Review Letters. "Here we've shown experimentally how electron pressure accelerates the process."

The physics team built a picture of the gradient and other parameters of reconnection from research conducted on the Magnetic Reconnection Experiment (MRX) at PPPL, the leading laboratory device for studying reconnection. The findings marked the first experimental confirmation of predictions made by earlier simulations performed by other researchers of the behavior of ions and electrons during reconnection. "The experiments demonstrate how the plasma can sustain a large electric field while preventing a large electric current from building up and halting the reconnection process," said Fox.

Among potential applications of the results:

• Predictions of space storms. Magnetic reconnection in the magnetosphere, the magnetic field that surrounds Earth, can set off geomagnetic "substorms" that disable communications and global positioning satellites (GPS) and disrupt electrical grids. Improved understanding of fast reconnection can help locate regions where the process triggering storms is ready to take place.
• Mitigation of the impact. Advanced warning of reconnection and the disruptions that may follow can lead to steps to protect sensitive satellite systems and electric grids.
• Improvement of fusion facility performance. The process observed in MRX likely plays a key role in producing what are called "sawtooth" instabilities that can halt fusion reactions. Understanding the process could open the door to controlling it and limiting such instabilities. "How sawtooth happens so fast has been a mystery that this research helps to explain," said Fox. "In fact, it was computer simulations of sawtooth crashes that first linked electron pressure to the source of fast reconnection."

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Experimental small molecule shows potential in preventing meth relapse

New research from The Scripps Research Institute (TSRI) suggests that the reason methamphetamine users find it so hard to quit -- 88 percent of them relapse, even after rehab -- is that meth takes advantage of the brain's natural learning process. The TSRI study in rodent models shows that ceasing meth use prompts new neurons to form in a brain region tied to learning and memory, suggesting that the brain is strengthening memories tied to drug-seeking behavior.

"New neuronal growth is normally thought of as a good thing, but we captured these new neurons assisting with 'bad' behaviors," said Chitra Mandyam, who led the research as an associate professor at TSRI before starting a new position at the Veterans Medical Research Foundation and the University of California, San Diego.

The scientists discovered that they could block relapse by giving animals a synthetic small molecule to stop new neurons from forming. This molecule, called Isoxazole-9 (Isx-9), also appeared to reverse abnormal neuronal growth that developed during meth use.

The new research was published this week in the journal Molecular Psychiatry.

Young Neurons Gone Bad

Neurons are born all the time in a process called neurogenesis. In a 2010 study, Mandyam and her colleagues at TSRI showed that increased neurogenesis is tied to a higher risk of drug relapse, but they weren't sure of the new neurons' role in the process. The researchers were especially curious about a "burst" of neurogenesis that occurs during abstinence from meth.

The new study may explain why the brain is so eager to make neurons during abstinence: meth hijacks the natural neurogenesis process.

Normally, new neurons help us learn by forming new circuits to connect rewards, like food, to reward-associated memories. For example, we learn early on that the refrigerator holds food. "In a non-drug environment, this is a healthy process," said Mandyam. But the brain isn't good at separating healthy rewards from the dangerous high of drug use.

Using rat models of meth addiction, the researchers showed that forced abstinence prompted the development of new neurons called granule cell neurons in a brain region called the dentate gyrus, which is associated with memory formation. These new neurons drove compulsive-like drug seeking and relapse by strengthening drug-associated memories. The rats learned to associate a particular location in their environment with meth use. Returning to this location during abstinence later served as a triggering cue -- prompting a recovering addict to relapse.

A Potential Way to Stop Relapse

Next, the researchers tested whether the synthetic small molecule Isx-9 could inhibit this process. Previous studies had shown that Isx-9 could block cell division of some types of cells, but it had not been tested as a way to block neurogenesis and fight meth relapse. Working closely with Professor Kim Janda's lab at TSRI, which supplied the molecule, Mandyam and her colleagues found that meth-addicted rats given Isx-9 during abstinence were less likely to relapse into drug use. Isx-9 indeed blocked neurogenesis, appearing to keep their brains from strengthening drug-associated memories. For these rats, the environment where they took the drug was no longer a strong trigger for relapse.

Interestingly, the researchers only saw the benefits of Isx-9 in rats that were "high responders" to meth. From the beginning of the experiment, some of the rats were simply not as interested in the drug -- Mandyam called them the "casual users." "Just like humans, animals also show remarkable individual differences in drug seeking," said Mandyam. She plans to further study these individual differences to better understand how to address addiction and recovery.

Isx-9 also appears to repair some of the structural changes seen in neurons exposed to meth. In high-responder rats, Isx-9 restored the neuronal structures crucial for normal cell signaling.

The researchers also plan to further investigate potential side effects of Isx-9, and Mandyam hopes future studies will set the stage to test Isx-9 in clinical trials for meth addiction.

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Helping the retina regenerate

A new report gives recommendations for regenerating retinal ganglion cells (RGCs), crucial neurons in the back of the eye that carry visual information to the brain. Authored by Monica Vetter, Ph.D., University of Utah, and Peter Hitchcock, Ph.D., University of Michigan, the report stems from a 2016 workshop sponsored by the National Eye Institute (NEI) Audacious Goals Initiative (AGI).

"Replacing RGCs is a major challenge for the AGI," said Steven Becker, Ph.D., who coordinates the initiative -- a sustained effort by the NEI to catalyze research aimed at restoring vision by regenerating the retina, the light-sensitive tissue in the back of the eye. Glaucoma and other optic neuropathies cause vision loss through the permanent destruction of RGCs. In humans, RGCs are incapable of regenerating on their own.

The report summarized two possible therapeutic strategies for RGC regeneration. The first would use stem cells to grow RGCs. These lab-grown cells would then be transplanted to a patient's retina. While preclinical testing has shown promise, the report details challenges to this approach. For starters, producing adequate quantities for therapy remains difficult and takes many weeks. And researchers are unsure how best to store RGCs for when patients need them. Another challenge is determining the optimal stage of cellular development for transplantation. Cells that are too naïve may develop into unintended cell types, while those that are more mature might not easily integrate into the retina.

The second approach -- the focus of the AGI workshop -- is to recruit other cell types in a patient's retina for reprogramming into RGCs. Amphibians do this naturally in response to RGC death from injury. Similarly, adult zebrafish regenerate RGCs by reprogramming cells in the retina called Müller glia. As outlined in the report, the workshop explored additional cell types for potential reprogramming, including retinal pigment epithelial cells, ciliary epithelial cells, amacrine cells, and astrocytes. According to the report, the key to unlocking these endogenous cell sources for RGC reprogramming is understanding the cues that direct their maturation and integration with other cells.

The report calls for research to better define the genetic factors and signaling pathways that promote endogenous cell reprogramming. Additionally, better characterization of the 30-plus types of RGCs is needed. Other key recommendations in the report include systematic comparisons of animal models that do and do not regenerate RGCs, criteria for evaluating RGCs, and imaging techniques to assess RGC integration in the retina.

The report appears in Translational Vision Science and Technology.

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Will grass become the new gasoline?

Researchers at Ghent University (Belgium, Europe) have developed a process that turns grass into biofuel.

In the quest of more sustainable fuel types, scientists at Ghent University have developed a way to turn grass into biofuel. Will we soon drive on 'grassoline'?

"Until now, grass has mainly served as feed for animals. But apart from that, grass can also be used as biofuel. Due to its vast abundance, grass is the perfect source of energy," scientist Way Cern Khor tells us. During his PhD research at Ghent University, Belgium, he investigated methods that can disintegrate and treat grass until it can be used as a fuel.

How it works

To improve its biodegradability, the grass is pretreated at first. Then bacteria are added. They convert the sugars in the grass into lactic acid and its derivatives.

This lactic acid can serve as an intermediate chemical to produce other compounds such as biodegradable plastics (PLA) or fuels.

The lactic acid then was converted into caproic acid, which was further converted into decane. And that's where the process ends: decane can be used in aviation fuel. [SP1]

Work in progress

Although it might sound revolutionary, there's still a lot to do before this becomes reality. Right now the amount of biofuel that can be made from grass is still limited to a few drops. The current process is very expensive, and engines should be adapted to this new kind of fuel.

"If we can keep working on optimizing this process in cooperation with the business world, we can come down on the price. And maybe in a few years we can all fly on grass!," Khor concludes.

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Medical News Today: Computational model of the brain shows what triggers Tourette 'tics'

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Bio-inspired energy storage: A new light for solar power

Inspired by an American fern, researchers have developed a groundbreaking prototype that could be the answer to the storage challenge still holding solar back as a total energy solution.

The new type of electrode created by researchers from RMIT University in Melbourne, Australia, could boost the capacity of existing integrable storage technologies by 3000 per cent.

But the graphene-based prototype also opens a new path to the development of flexible thin film all-in-one solar capture and storage, bringing us one step closer to self-powering smart phones, laptops, cars and buildings.

The new electrode is designed to work with supercapacitors, which can charge and discharge power much faster than conventional batteries. Supercapacitors have been combined with solar, but their wider use as a storage solution is restricted because of their limited capacity.

RMIT's Professor Min Gu said the new design drew on nature's own genius solution to the challenge of filling a space in the most efficient way possible -- through intricate self-repeating patterns known as "fractals."

"The leaves of the western swordfern are densely crammed with veins, making them extremely efficient for storing energy and transporting water around the plant," said Gu, Leader of the Laboratory of Artificial Intelligence Nanophotonics and Associate Deputy Vice-Chancellor for Research Innovation and Entrepreneurship at RMIT.

"Our electrode is based on these fractal shapes -- which are self-replicating, like the mini structures within snowflakes -- and we've used this naturally-efficient design to improve solar energy storage at a nano level.

"The immediate application is combining this electrode with supercapacitors, as our experiments have shown our prototype can radically increase their storage capacity -- 30 times more than current capacity limits.

"Capacity-boosted supercapacitors would offer both long-term reliability and quick-burst energy release -- for when someone wants to use solar energy on a cloudy day for example -- making them ideal alternatives for solar power storage."

Combined with supercapacitors, the fractal-enabled laser-reduced graphene electrodes can hold the stored charge for longer, with minimal leakage. The fractal design reflected the self-repeating shape of the veins of the western swordfern, Polystichum munitum, native to western North America.

Lead author, PhD researcher Litty Thekkekara, said because the prototype was based on flexible thin film technology, its potential applications were countless.

"The most exciting possibility is using this electrode with a solar cell, to provide a total on-chip energy harvesting and storage solution," Thekkekara said.

"We can do that now with existing solar cells but these are bulky and rigid. The real future lies in integrating the prototype with flexible thin film solar -- technology that is still in its infancy.

"Flexible thin film solar could be used almost anywhere you can imagine, from building windows to car panels, smart phones to smart watches. We would no longer need batteries to charge our phones or charging stations for our hybrid cars.

"With this flexible electrode prototype we've solved the storage part of the challenge, as well as shown how they can work with solar cells without affecting performance. Now the focus needs to be on flexible solar energy, so we can work towards achieving our vision of fully solar-reliant, self-powering electronics."

The research is published in Scientific Reports on Friday 31 March.

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Hair testing shows high prevalence of new psychoactive substance use

In the last decade hundreds of new psychoactive substances (NPS) have emerged in the drug market, taking advantage of the delay occurring between their introduction into the market and their legal ban. According to the Drug Enforcement Agency (DEA) NPS describes a recently emerged drug that may pose a public health threat. The DEA issues a quarterly Emerging Threat Report, which catalogues the newest identified NPS.

NPS tend to mimic the psychotropic effects of traditional drugs of abuse, but their acute and chronic toxicity, and side-effects are largely unknown. While seizure data from the DEA is often used to indicate what new drugs are being sold in the US, there is a lack of research examining and confirming who has been using such drugs.

Joseph J. Palamar, PhD, MPH, a New York University researcher, has been researching incidental and intentional use of NPS by young adults. His current line of inquiry has focused on survey methods, qualitative interviews, and hair sampling to ascertain frequency and type of NPS use by nightclub-goers -- a demographic which traditionally has a relaxed view towards recreational drug experimentation and use.

NPS are common adulterants in drugs such as ecstasy (MDMA), which has seen an increase in popularity since it became marketed as "Molly." Ironically, "Molly" connotes a product that is pure MDMA. In a related study, Palamar and his team found that four out of ten nightclub/festival attendees who used ecstasy or "Molly" tested positive for "bath salts" despite reporting no use.

In their current study, "Hair Testing for Drugs of Abuse and New Psychoactive Substances in a High-Risk Population," Dr. Alberto Salomone, an affiliated researcher at the Centro Regionale Antidoping e di Tossicologia "A. Bertinaria," Orbassano, Turin, Italy and Dr. Palamar, affiliated with NYU's Center for Drug Use and HIV Research (CDUHR), collected hair samples from 80 young adults outside of New York City nightclubs and dance festivals, from July through September of 2015. Hair samples from high-risk nightclub and dance music attendees were tested for 82 drugs and metabolites (including NPS) using ultra-high performance liquid chromatography-tandem mass spectrometry.

"Hair analysis represents a reliable and well-established means of clinical and forensic investigations to evaluate drug exposure, said Dr. Salomone. "Hair is the most helpful specimen when either long-time retrospective information on drug consumption is of interest." "Most NPS can no longer be detected in urine, blood, or saliva within hours or days after consumption, but hair is particularly beneficial because many drugs can be detected months after use."

Of the eighty samples, twenty-six tested positive for at least one NPS -- the most common being a "bath salt" (synthetic cathinone) called butylone (present in twenty-five samples). The "bath salts" methylone and even alpha-PVP (a.k.a.: "Flakka") were also detected. The researchers find the presence of Flakka alarming as this drug has been associated with many episodes of erratic behavior and even death in Florida. Other new drugs detected included new stimulants called 4-FA and 5/6-APB.

"We found that many people in the nightclub and festival scene have been using new drugs and our previous research has found that many of these people have been using unknowingly," said Dr. Palamar, also an assistant professor of Population Health at NYU Langone Medical Center (NYULMC).

Hair analysis proved a powerful tool to Drs. Salomone and Palamar and their team, allowing them to gain objective biological drug-prevalence information, free from possible biases of unintentional or unknown intake and untruthful reporting of use.

"Such testing can be used actively or retrospectively to validate survey responses and inform research on consumption patterns," notes Dr. Palamar.

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Hair testing shows high prevalence of new psychoactive substance use

New treatment for antibiotic resistant bacteria and infectious disease

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Not a pipe dream anymore. Space-farming: A long legacy leading us to Mars

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Methane emissions from trees

A new study from the University of Delaware is one of the first in the world to show that tree trunks in upland forests actually emit methane rather than store it, representing a new, previously unaccounted source of this powerful greenhouse gas.

Methane is about 25 times stronger than carbon dioxide, with some estimates as high as 33 times stronger due to its effects when it is in the atmosphere.

Because of methane's global warming potential, identifying the sources and "sinks" or storehouses of this greenhouse gas is critical for measuring and understanding its implications across ecosystems.

Upland forest soils usually take up and store methane, but this effect can be counteracted by methane emissions from tree trunks, the research team from UD's College of Agriculture and Natural Resources found. Their work is published in the scientific journal Ecosystems.

"We believe our work can help fill in some gaps in methane budgets and environmental processes in global ecosystem models," said the study's leader, Rodrigo Vargas, assistant professor in the Department of Plant and Soil Sciences in UD's College of Agriculture and Natural Resources.

Shreeram Inamdar, professor of watershed hydrology and biogeochemistry, is co-investigator on the project with Vargas, and doctoral student Daniel Warner is the lead author of the paper. The research was funded by the U.S. Department of Agriculture, with additional support from Delaware's Federal Research and Development Matching Grant Program.

Maryland study site

In a 30-acre area of upland forest at Fair Hill Natural Resources Management Area in nearby Cecil County, Maryland, the researchers tested a cluster of trees, soil and coarse woody debris (CWD) -- dead wood lying on the forest floor in various stages of decomposition -- to measure fluxes of methane and carbon dioxide.

The researchers used a state-of-the-art greenhouse gas analyzer based on laser absorption technology, called Off-Axis Integrated Cavity Output Spectroscopy (OA-ICOS), which looks similar to a proton pack from the movie "Ghostbusters."

Warner visited the site over the course of one growing season, April to December, and measured the carbon dioxide and methane fluxes of the soil, tree trunks and CWD to determine whether those three components were sources or sinks of these greenhouse gases.

Soils and CWD fluxes

In terms of carbon dioxide, research on the fluxes of tree trunks, known as stem respiration, and soil, known as soil respiration, has been done for decades, but research to determine the importance of carbon fluxes with regard to CWD still lags behind.

For methane, however, it's a different story. While studies have been done on methane fluxes in connection to soils, which usually consume the methane and are considered methane sinks, there are very few that deal with CWD and tree trunks in upland soils.

"What research has been done is generally lab incubations of wood where they measure how much methane is released over time. What we've found in this study is that some coarse woody debris acts kind of like the soil and consumes methane while other pieces of coarse woody debris emit small amounts of methane, which is also what we saw with living tree trunks," said Warner.

To understand the differences between the actions of the CWD, Warner and colleagues found that fresher CWD has a positive methane flux, which is similar to how a living tree behaves.

"When a tree falls over, it's still functionally the same in terms of methane emissions. Over time, as it decays, my theory is that it gets colonized by soil bacteria that consume methane and it shifts to behave more like the soil, resulting in a methane sink," said Warner.

The researchers also found that CWD had a high rate of variability when it came to methane emissions.

"As it decays it becomes a lot more variable. Some of the super-decayed wood was still releasing methane but a lot of it was consuming methane," said Warner. "If you have a CWD pool with less diversity regarding the degree of decomposition, you can expect it to play a more uniform role in terms of methane emissions or sinks."

Tree trunks and methane fluxes

While tree trunks have been known to release carbon dioxide, this research showed that they were also releasing methane.

"The tree trunks constantly have low but detectable emissions of methane. Soils are providing an environmental service of sequestering this potent greenhouse gas, but the trunks are releasing methane equivalent to 4 percent of what could be captured by CWD and soils at the ecosystem scale," said Vargas.

Overall, the tree trunks acted as a source of carbon dioxide and as a small source of methane, but the magnitude of gases emitted varied with the species.

Tulip poplar was one species that released a lot of methane and carbon dioxide, whereas beech trees released the most methane within the forest but emitted very little carbon dioxide.

"It might be some species-specific trait that's controlling the flux," said Warner.

Temperature threshold

Temperature also played a key role in regulating the magnitude of the fluxes.

"Methane in soils seem to follow a temperature gradient where higher temperatures are related to higher uptake of methane but that's not necessarily the case for CWD or for tree trunks," said Vargas.

Warner said it's hard to develop a temperature relationship with methane because there are two processes that oppose each other.

"You have things in the soil producing methane -- known as methanogenesis -- things consuming it -- known as methanotrophy -- and so as you warm up, it's more kind of like a shot gun where the magnitudes of methane scatter out more as it gets warmer; suggesting that other factors beyond temperature regulate methane emissions," said Warner.

They found that beyond a threshold of 17 degrees Celsius for soil temperature, the variability of methane consumption expands dramatically.

"Under 17 degrees, temperature is a key driver of methane flux but above 17 degrees, there are other drivers that will influence methane production," said Vargas.

Soil hot spots

As for where the methane originated, Warner said it's still a science frontier, but this study provides enough clues to give the researchers some theories.

The first one is that methane is produced in hot spots in the soil.

"By hot spot, we mean a place where conditions are conducive to methane production and then that methane is sucked up by the tree roots, transported through its vascular system and released out of its trunk," said Warner. "We know that happens in wetlands but in uplands, maybe it happens in one specific spot and nowhere else."

The other mechanism that could be causing methane fluxes from trunks is internal rotting or infection inside the tree, which produces an environment where methanogenic bacteria can survive and then methane diffuses out of the tree.

"At this moment, the mechanisms of methane production in upland forests are not clear. Methane can be either transported from the soils upward inside the stem and diffused to the atmosphere or produced inside the stem by fungi or archaea -- single-celled microorganisms," said Vargas.

Next steps

Both Warner and Vargas agreed that the next steps should be to test the generality of these observations across different forests, and identify the mechanisms of methane production and transport in tree trunks. Finally, they suggest that global and ecosystem models should take into account methane produced from tree trunks as a new source of methane to the atmosphere.

"When people develop ecosystem to global scale methane budgets, there's always a chunk in which it is uncertain from where that methane is coming. Methane emissions by vegetation and tree trunks are seen as a newly-considered source that might bring that budget closer in to our estimates. It's good to keep chipping away at that," said Warner.

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Methane emissions from trees

Satellite galaxies at edge of Milky Way coexist with dark matter

Research conducted by scientists at Rochester Institute of Technology rules out a challenge to the accepted standard model of the universe and theory of how galaxies form by shedding new light on a problematic structure.

The vast polar structure -- a plane of satellite galaxies at the poles of the Milky Way -- is at the center of a tug-of-war between scientists who disagree about the existence of mysterious dark matter, the invisible substance that, according to some scientists, comprises 85 percent of the mass of the universe.

A paper accepted for publication in the Monthly Notices for the Royal Astronomical Society bolsters the standard cosmological model, or the Cold Dark Matter paradigm, by showing that the vast polar structure formed well after the Milky Way and is an unstable structure.

The study, "Is the Vast Polar Structure of Dwarf Galaxies a Serious Problem for CDM?" was co-authored by Andrew Lipnicky, a Ph.D. candidate in RIT's astrophysical sciences and technology program, and Sukanya Chakrabarti, assistant professor in RIT's School of Physics and Astronomy, whose grant from the National Science Foundation supported the research.

Lipnicky and Chakrabarti analyze the distribution of the classical Milky Way dwarf galaxies that form the vast polar structure and compares it to simulations of the "missing" or subhalo dwarf galaxies thought to be cloaked in dark matter.

Using motion measurements, the authors traced the orbits of the classical Milky Way satellites backward in time. Their simulations showed the vast polar structure breaking up and dispersing, indicating that the plane is not as old as originally thought and formed later in the evolution of the galaxy. This means that the vast polar structure of satellite galaxies may be a transient feature, Chakrabarti noted.

"If the planar structure lasted for a long time, it would be a different story," Chakrabarti said. "The fact that it disperses so quickly indicates that the structure is not dynamically stable. There is really no inconsistency between the planar structure of dwarf galaxies and the current cosmological paradigm."

The authors removed the classical Milky Way satellites Leo I and Leo II from the study when orbital analyses determined that the dwarf galaxies were not part of the original vast polar structure but later additions likely snatched from the Milky Way. A comparison excluding Leo I and II reveals a similar plane shared by classical galaxies and their cloaked counterparts.

"We tried many different combinations of the dwarf galaxies, including distributions of dwarfs that share similar orbits, but in the end found that the plane always dispersed very quickly," Lipnicky said.

Opposing scientific thought rejects the existence of dark matter. This camp calls into question the standard cosmological paradigm that accepts both a vast polar structure of satellite galaxies and a hidden plane of dark-matter cloaked galaxies. Lipnicky and Chakrabarti's study supports the co-existence of these structures and refutes the challenge to the accepted standard model of the universe.

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Materials provided by Rochester Institute of Technology. Original written by Susan Gawlowicz. Note: Content may be edited for style and length.

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Satellite galaxies at edge of Milky Way coexist with dark matter

NIH funding helps generate private-sector patents

Research grants issued by the National Institutes of Health (NIH) contribute to a significant number of private-sector patents in biomedicine, according to a new study co-authored by an MIT professor.

The study, published in the journal Science, examines 27 years of data and finds that 31 percent of NIH grants, which are publicly funded, produce articles that are later cited by patents in the biomedical sector.

"The impact on the private sector is a lot more important in magnitude than what we might have thought before," says Pierre Azoulay, a professor at the MIT Sloan School of Management, who is one of the authors of the paper.

After reviewing over 365,000 grants -- making this a uniquely large study -- the research also finds that over 8 percent of NIH grants generate a patent directly.

Intriguingly, the researchers also find no significant difference between "basic" or "applied" research grants in terms of the frequency with which those projects helped generate patents; both kinds of research spill over into productive private-sector uses.

"If you thought the NIH exists in an ivory tower, you're wrong," Azoulay says. "They are the nexus of knowledge that really unifies two worlds."

The paper, "The Applied Value of Public Investments in Biomedical Research," is co-authored by Azoulay, who is the International Programs Professor of Management at MIT Sloan; Danielle Li PhD '12, an assistant professor at Harvard Business School; and Bhaven Sampat, an associate professor at Columbia University's Mailman School of Public Health.

Decades of grants

The NIH, which has its main campus in Bethesda, Maryland, encompasses multiple research institutes and is the world's biggest source of public funding for biomedical research, dispersing about $32 billion annually in grants.

To conduct the study, the scholars examined 365,380 NIH grants funded between 1980 and 2007 -- nearly every NIH grant awarded for decades. Exactly 30,829 were the direct basis for patents; 17,093 of those were so-called "Bayh-Dole" patents issued to universities and hospitals, something federal legislation made possible starting in 1980.

Of the NIH grants, 112,408 were additionally cited in a total of 81,462 private-sector patents.

And as the authors put it in the new paper, even these NIH-backed research projects that are indirectly cited in later patents "demonstrate the additional reach that publicly funded science can have by building a foundation for private-sector R&D."

Azoulay, an economist who studies the production and dissemination of scientific knowledge, says the bottom-line figures in the study -- the 31 percent and 8 percent of NIH grants that contribute to and more directly generate patents -- strike him as being significantly large because of the broad scope of research the NIH supports.

"There is a lot of research we wouldn't necessarily expect to be relied upon in a patent," Azoulay explains.

He also noted that such research can be characterized as either "basic" or "applied"; the researchers found little difference in the long-term patent-creating productivity of those categories.

For instance, some research projects can be considered more directly "disease-oriented" than others, but even by this yardstick, the frequency of patent generation does not vary greatly. About 35 percent of "disease-oriented" NIH grants led to patents, compared to 30 percent otherwise.

Overall, Azoulay says, the flow of knowledge from NIH research projects to the commercial market seems clear.

"Grants produce papers, and papers are cited by patents used by pharmaceutical firms," says Azoulay. "It's hard to think of an innovation [in biomedicine] that doesn't have a patent."

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Prudence, impatience and laziness: Are these contagious personality traits?

People tend to unconsciously imitate others' prudent, impatient or lazy attitudes, according to a study published in PLOS Computational Biology.

"Prudence," "impatience" or "laziness" are typically thought of as entrenched personality traits that guide how people weigh the cost of risk, delay and effort (respectively). However, new research shows that people's attitudes towards effort, delay, or risk drift towards those of others.

Jean Daunizeau and Marie Devaine, from INSERM, Paris, combined mathematical modelling and cognitive psychology to explore the laws that govern such attitude alignment. The authors asked 56 participants to make a series of decisions involving risks, delays or efforts, both before and after having observed the decisions of fictitious participants (in fact: artificial intelligence algorithms) whose prudent, patient and lazy attitudes were sensibly calibrated.

The study results show that participants are bound to a "false-consensus" bias, i.e. they believe without evidence that the attitudes of others resemble their own. It also shows that people exhibit a "social influence" bias, i.e. their attitude tends to become more similar to those of people around them. Intriguingly, the social influence bias is partially determined by the false-consensus bias. In brief, it first increases with false-consensus (for small false-consensus biases), but then decreases with false-consensus (for large false-consensus biases). Note that participants seem to be mostly unaware of these biases.

Critically, mathematical simulations demonstrate that both biases, and the surprising interaction between them, are hallmarks of a unique mechanism that is ideally suited to learning both about and from others' covert attitudes. This is at odds with the conventional view that attitude alignment is an automatism that is triggered by the need to experience (partly deluded) feelings of social conformity.

"Our work is in line with an ongoing effort tending toward a computational (i.e. quantitative and refutable) understanding of human and animal cognition. In particular, we showed that formal information and decision theories provide invaluable insights regarding the nature and relationship of puzzling biases of social cognition," say the researchers.

The authors are currently applying this work to assess whether this form of attitude alignment may differ in people suffering from neuropsychiatric conditions, such as autism spectrum disorder and schizophrenia.

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Aging: Cell coordination breakdown

Researchers from the European Bioinformatics Institute (EMBL-EBI), University of Cambridge, the Wellcome Trust Sanger Institute and the Cancer Research UK-Cambridge Institute (CRUK-CI) have shed light on a long-standing debate about why the immune system weakens with age. Their findings, published in Science, show that immune cells in older tissues lack coordination and exhibit much more variability in gene expression compared with their younger counterparts.

Settling the debate

We've all witnessed the progressive decline of function that comes with ageing, but what exactly causes this decline -- and why does it happen at different rates for different parts of the body? To find answers, scientists need to unpick all of the mechanisms of ageing at the molecular level, for every tissue. Today's study focused on immune tissue: specifically, CD4+ T cells.

The immune system is like a symphony orchestra, with many different types and subtypes of cells working together to fight infections. But as the immune system ages, its response to infection weakens for reasons that are not yet clear. One long-standing debate amongst scientists concerns two central hypotheses: either the functional degradation is caused by a loss of cellular performance, or it is down to a loss of coordination among cells.

To resolve the debate, scientists have studied many different cell types, analysing 'average' gene expression profiles. Today's study employed high-resolution single-cell sequencing technology to create new insights into how cell-to-cell variability is linked with ageing. The researchers sequenced the RNA of naïve and memory CD4+ T cells in young and old mice, in both stimulated and unstimulated states.

Their findings clearly showed that loss of coordination is a key component of the impaired immune performance caused by T cell ageing.

The DNA smoothie

"You could think of DNA sequencing as a fruit smoothie," explains John Marioni, Group Leader at EMBL-EBI and at CRUK-CI. "Traditional sequencing technology is a bit like taking a sip of the smoothie, then trying to guess what the ingredients are. Single-cell genomics now lets us study the ingredients individually, so we get direct insight into the constituent parts. Extrapolating, this means that single-cell sequencing allows researchers to individually look at thousands of genes at any given time."

A phalanx of immune cells

Duncan Odom, Group Leader at the University of Cambridge's Cancer Research UK Cambridge Institute and associate faculty at the Wellcome Trust Sanger Institute, shares a further analogy to explain how immune cells fight infection.

"Imagine the immune system as a 'cell army', ready to protect the body from infection," says Odom. "Our research revealed that this army is well coordinated in young animals, with all the cells working together and operating like a Greek phalanx to block the infection."

Odom goes on to explain that this tight coordination makes the immune system stronger, and allows it to fight infection more effectively. The team's study shows that as the animal gets older, cell coordination breaks down.

"Although individual cells might still be strong, the lack of coordination between them makes their collective effectiveness lower," Odom concludes.

Older and more variable

Previous studies have shown that in young animals, immunological activation results in tightly regulated gene expression (see Box). This study further reveals that activation results in a decrease in cell-to-cell variability. Ageing increased the heterogeneity of gene expression in populations of two mice species, as well as in different types of immune cells. This suggests that increased cell-to-cell transcriptional variability may be a hallmark of ageing across most mammalian tissues.

"There is a great deal of interest in how biological ageing happens, but not much is known about molecular ageing," says Celia Pilar Martinez-Jimenez, experimental lead and Postdoctoral Fellow at the Sanger Institute and CRUK-CI. "This research initiative explored a new facet of cell response to disease, while also tackling questions related to ageing."

Nils Eling, computational lead of the project and PhD student at EMBL-EBI and CRUK-CI highlights that "the advantage of analysing gene expression from single cells is to detect how cell populations synchronise their response. It is interesting to see that ageing strongly distorts this response -- a phenomenon which could not be observed before."

The interdisciplinary study paves the way for a more in-depth exploration of the mechanisms by which different types of cells age. It also illustrates the potential of single-cell sequencing to enable a richer understanding of cell development and activity.

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Triple-threat cancer-fighting polymer capsules for guided drug delivery

Chemists at the University of Alabama at Birmingham have designed triple-threat cancer-fighting polymer capsules that bring the promise of guided drug delivery closer to preclinical testing.

These multilayer capsules show three traits that have been difficult to achieve in a single entity. They have good imaging contrast that allows detection with low-power ultrasound, they can stably and efficiently encapsulate the cancer drug doxorubicin, and both a low- and higher-power dose of ultrasound can trigger the release of that cargo.

These three features create a guided drug delivery system to target solid tumors. Therapeutic efficacy can be further improved through surface modifications to boost targeting capabilities. Diagnostic low-power ultrasound then could visualize the nanocapsules as they concentrated in a tumor, and therapeutic higher-dose ultrasound would release the drug at ground zero, sparing the rest of the body from dose-limiting toxicity.

This precise control of when and where doxorubicin or other cancer drugs are released could offer a noninvasive alternative to cancer surgery or systemic chemotherapy, the UAB researchers report in the journal ACS Nano, which has an impact factor of 13.3.

"We envision an entirely different approach to treating solid human tumors of numerous pathologic subtypes, including common metastatic malignancies such as breast, melanoma, colon, prostate and lung, utilizing these capsules as a delivery platform," said Eugenia Kharlampieva, Ph.D., an associate professor in the Department of Chemistry, UAB College of Arts and Sciences. "These capsules can protect encapsulated therapeutics from degradation or clearance prior to reaching the target and have ultrasound contrast as a means of visualizing the drug release. They can release their encapsulated drug cargo in specific locations via externally applied ultrasound exposure."

Kharlampieva -- who creates her novel "smart" particles while working at the intersection of polymer chemistry, nanotechnology and biomedical science -- says there is an urgent, and so far unmet, need for such an easily fabricated, guided drug delivery system.

The UAB researchers, led by Kharlampieva and co-first authors Jun Chen and Sithira Ratnayaka, use alternating layers of biocompatible tannic acid and poly(N-vinylpyrrolidone), or TA/PVPON, to build their microcarriers. The layers are formed around a sacrificial core of solid silica or porous calcium carbonate that is dissolved after the layers are complete.

By varying the number of layers, the molecular weight of PVPON or the ratio of shell thickness to capsule diameter, the researchers were able to alter the physical traits of the capsules and their sensitivity to diagnostic ultrasound, at power levels below the FDA maximum for clinical imaging and diagnosis.

For example, one-fourth of empty microcapsules made with four layers of TA/low-molecular weight PVPON were ruptured by three minutes of ultrasound, while capsules made of 15 layers of TA/low-molecular weight PVPON or capsules made from four layers of TA/high-molecular weight PVPON showed no rupture. The ruptured capsules had a lower mechanical rigidity that made them more sensitive to ultrasound pressure changes. Experiments showed that the ratio of the thickness of the capsule wall to the diameter of the capsule is a key variable for sensitivity to rupture.

To test the ultrasound imaging contrast of the microcapsules, the UAB researchers made capsules that were 5 micrometers wide, or about two times wider than the capsules used in the rupture experiments. This size is small enough to still pass through capillaries in the lung, while a larger size for various microparticles is known to greatly improve ultrasound contrast. Red blood cells, for a size comparison, have a diameter of about 6 to 8 micrometers.

Researchers found that 5-micrometer-wide, empty capsules that were made with eight layers of TA/low-molecular weight PVPON showed an ultrasound contrast comparable to the commercially available microsphere contrast agent Definity. When the UAB capsules -- which have a shell thickness of about 50 nanometers -- were loaded with doxorubicin, the ultrasound imaging contrast increased two- to eightfold compared to empty capsules, depending on the mode of ultrasound imaging used. These doxorubicin-loaded capsules were highly stable, with no change in ultrasound imaging contrast after six months of storage. Exposure to serum, known to deposit proteins on various microparticles, did not extinguish the ultrasound imaging contrast of the TA/PVPON microcapsules.

A therapeutic dose of ultrasound was able to rupture 50 percent of the 5-micrometer, doxorubicin-loaded microcapsules, releasing enough doxorubicin to induce 97 percent cytotoxicity in human breast adenocarcinoma cells in culture. Adenocarcinoma cells that were incubated with intact doxorubicin-loaded microcapsules remained viable.

Thus, Kharlampieva says, these TA/PVPON capsules have strong potential as "theranostic" agents for efficient cancer therapy in conjunction with ultrasound. The term theranostic refers to nanoparticles or microcapsules that can double as diagnostic imaging agents and as therapeutic drug-delivery carriers.

The next important preclinical step, Kharlampieva says, in collaboration with Mark Bolding, Ph.D., assistant professor in the UAB Department of Radiology, and Jason Warram, Ph.D., assistant professor in the UAB Department of Otolaryngology, will be studies in animal models to explore how long the UAB capsules persist in blood circulation and where they distribute in the body.

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Sculpting optical microstructures with slight changes in chemistry

In 2013, materials scientists at the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) and the Wyss Institute of Biologically Inspired Engineering, grew a garden of self-assembled crystal microstructures. Now, applied mathematicians at SEAS and Wyss have developed a framework to better understand and control the fabrication of these microstructures.

Together, the researchers used that framework to grow sophisticated optical microcomponents.

The research is published in Science.

When it comes to the fabrication of multifunctional materials, nature has humans beat by miles. Marine mollusks can embed photonic structures into their curved shells without compromising shell strength; deep sea sponges evolved fiber optic cables to direct light to symbiotically living organisms; and brittlestars cover their skeletons with lenses to focus light into the body to "see" at night. During growth, these sophisticated optical structures tune tiny, well-defined curves and hollow shapes to better guide and trap light.

Manufacturing complex bio-inspired shapes in the lab is often time consuming and costly. The breakthrough in 2013 was led by materials scientists Joanna Aizenberg, the Amy Smith Berylson Professor of Materials Science and Chemistry and Chemical Biology and core faculty member of the Wyss Institute and former postdoctoral fellow Wim L. Noorduin. The research allowed researchers to fabricate delicate, flower-like structures on a substrate by simply manipulating chemical gradients in a beaker of fluid. These structures, composed of carbonate and glass, form a bouquet of thin walls.

What that research lacked then was a quantitative understanding of the mechanisms involved that would enable even more precise control over these structures.

Enter the theorists.

Inspired by the theory to explain solidification and crystallization patterns, L. Mahadevan, the Lola England de Valpine Professor of Applied Mathematics, Physics, and Organismic and Evolutionary Biology, and postdoctoral fellow C. Nadir Kaplan, developed a new geometrical framework to explain how previous precipitation patterns grew and even predicted new structures.

Mahadevan is also core member of the Wyss Institute.

In experiments, the shape of the structures can be controlled by changing the pH of the solution in which the shapes are fabricated.

"At high pH, these structures grow in a flat manner and you get flat shapes, like side of a vase," said Kaplan, co-first author of the paper. "At low pH, the structure starts to curve and you get helical structures."

When Kaplan solved the resulting equations as a function of pH, with a mathematical parameter standing in for the chemical change, he found that he could recreate all the shapes developed by Noorduin and Aizenberg -- and come up with new ones.

"Once we understood the growth and form of these structures and we could quantify them; our goal was to use the theory to come up with a strategy to build optical structures from the bottom up," said Kaplan.

Kaplan and Noorduin worked together to grow resonators, waveguides and beam splitters.

"When we had the theoretical framework, we were able to show the same process experimentally," said Noorduin, co-first author. "Not only were we able to grow these microstructures, but we could also demonstrate their ability to conduct light."

Noorduin is now a group lead at the Dutch materials research organization AMOLF.

"The approach may provide a scalable, inexpensive and accurate strategy to fabricate complex three-dimensional microstructures, which cannot be made by top-down manufacturing and tailor them for magnetic, electronic, or optical applications," said Joanna Aizenberg, co-author of the paper.

"Our theory reveals that, in addition to growth, carbonate-silica structures can also undergo bending along the edge of their thin walls," said Mahadevan, the senior author of the paper. "This additional degree of freedom is typically lacking in conventional crystals, such as a growing snowflake. This points to a new kind of growth mechanism in mineralization, and because the theory is independent of absolute scale, it may be adapted to other geometrically constrained growth phenomena in physical and biological systems."

Next, the researchers hope to model how groups of these structures compete against each other for chemicals, like trees in a forest competing for sunlight.

The research was coauthored by Ling Li, Roel Sadza and Laura Folkertsma. The research was supported by the National Science Foundation, the Kavli Institute for Bionano Science and Technology at Harvard University and Harvard MRSEC.

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Solar wind stripped Martian atmosphere away

Solar wind and radiation are responsible for stripping the Martian atmosphere, transforming Mars from a planet that could have supported life billions of years ago into a frigid desert world, according to new results from NASA's MAVEN (Mars Atmosphere and Volatile Evolution Mission) spacecraft led by the University of Colorado Boulder.

"We've determined that most of the gas ever present in the Mars atmosphere has been lost to space," said Bruce Jakosky, principal investigator for MAVEN and a professor at the Laboratory for Atmospheric and Space Physics (LASP). "The team made this determination from the latest result, which reveals that about 65 percent of the argon that was ever in the atmosphere has been lost to space."

Jakosky is lead author of a paper on this research to be published in Science on Friday. Marek Slipski, a LASP graduate student, co-authored the study.

MAVEN team members had previously announced measurements showing that atmospheric gas was being lost to space and that described the processes by which atmosphere was being stripped away. The present analysis uses measurements of today's atmosphere to give the first estimate of how much gas has been removed through time.

Liquid water, essential for life, is not stable on Mars' surface today because the atmosphere is too cold and thin to support it. However, evidence such as features resembling dry riverbeds and minerals that only form in the presence of liquid water indicates the ancient Martian climate was much different -- warm enough for water to flow on the surface for extended periods.

There are many ways a planet can lose some of its atmosphere. For example, chemical reactions can lock gas away in surface rocks or an atmosphere can be eroded by radiation and wind from the planet's parent star. The new result reveals that solar wind and radiation were responsible for most of the atmospheric loss on Mars and that the depletion was enough to transform the Martian climate. The solar wind is a thin stream of electrically conducting gas constantly blowing from the surface of the sun.

Young stars have far more intense ultraviolet radiation and winds, so atmospheric loss by these processes was likely much greater early in Mars' history, and these processes may have been the dominant ones controlling the planet's climate and habitability, according to the team. It's possible that microbial life could have existed at the surface early in Mars' history. As the planet cooled off and dried up, any life could have been driven underground or forced into occasional or rare surface oases.

Jakosky and his team got the result by measuring the atmospheric abundance of two different isotopes of argon gas. Isotopes are atoms of the same element with different masses. Because the lighter of the two isotopes escapes to space more readily, it will leave the gas remaining behind enriched in the heavier isotope. The team used this enrichment together with how it varied with altitude in the atmosphere to estimate what fraction of the atmospheric gas has been lost to space.

As a "noble gas" argon cannot react chemically with anything so it won't get sequestered in rocks, and the only process that can remove it to space is a physical process called "sputtering" by the solar wind. In sputtering, ions picked up by the solar wind impact Mars at high speeds and physically knock atmospheric gas into space. The team tracked argon because it can be removed only by sputtering. Once they determined the amount of argon lost by sputtering, they could use the efficiency of sputtering to determine the sputtering loss of other atoms and molecules, including carbon dioxide (CO2).

CO2 is of interest because it is the major constituent of Mars' atmosphere and because it's an efficient greenhouse gas that can retain heat and warm the planet.

"We determined that the majority of the planet's CO2 also has been lost to space by sputtering," said Jakosky. "There are other processes that can remove CO2, so this gives the minimum amount of CO2 that's been lost to space."

The team made its estimate using data on the Martian upper atmosphere from MAVEN's Neutral Gas and Ion Mass Spectrometer (NGIMS) instrument supported by measurements from the Martian surface made by NASA's Sample Analysis at Mars (SAM) instrument on board the Curiosity rover.

"The combined measurements enable a better determination of how much Martian argon has been lost to space over billions of years," said Paul Mahaffy of NASA's Goddard Space Flight Center in Greenbelt, Maryland. Mahaffy, a co-author of the paper, is principal investigator on the SAM instrument and lead on the NGIMS instrument, both of which were developed at NASA Goddard.

"Using measurements from both platforms points to the value of having multiple missions that make complementary measurements," said Mahaffy.

NASA Goddard manages the MAVEN project and MSL/Curiosity is managed by NASA's Jet Propulsion Laboratory in Pasadena, California.

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Solar wind stripped Martian atmosphere away

A decorated raven bone discovered in Crimea may provide insight into Neanderthal cognition

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Melting sea ice may lead to more life in the sea

When spring arrives in the Arctic, both snow and sea ice melt, forming melt ponds on the surface of the sea ice. Every year, as global warming increases, there are more and larger melt ponds.

Melt ponds provide more light and heat for the ice and the underlying water, but now it turns out that they may also have a more direct and potentially important influence on life in the Arctic waters.

Mats of algae and bacteria can evolve in the melt ponds, which can provide food for marine creatures. This is the conclusion of researchers in the periodical, Polar Biology.

Own little ecosystems

• The melt ponds can form their own little ecosystem. When all the sea ice melts during the summer, algae and other organisms from melt ponds are released into the surrounding seawater. Some of this food is immediately ingested by creatures living high up in the water column. Other food sinks to the bottom and gets eaten by seabed dwellers, explains Heidi Louise Sørensen, who is the principal author of the scientific article, continuing:
• Given that larger and larger areas of melt ponds are being formed in the Arctic, we can expect the release of more and more food for creatures in the polar sea.

Heidi Louise Sørensen studied the phenomenon in a number of melt ponds in North-Eastern Greenland as part of her PhD thesis at University of Southern Denmark (SDU).

Bo Thamdrup and Ronnie Glud of SDU, and Erik Jeppesen and Søren Rysgaard of Aarhus University also contributed to the work.

Food for seals and sea cucumbers

In the upper part of the water column it is mainly krill and copepods that benefit from the nutrient-rich algae and bacteria from melt ponds. These creatures are eaten by various larger animals, ranging from amphipods to fish, seals and whales. Deeper down, it is seabed dwellers such as sea cucumbers and brittle stars that benefit from the algae that sink down.

For some time now, researchers have been aware that simple biological organisms can evolve in melt ponds -- they may even support very diverse communities. But so far it has been unclear why sometimes there are many organisms in the ponds, and on other occasions virtually none.

According to the new study, 'nutrients' is the keyword. When nutrients such as phosphorus and nitrogen find their way into a melt pond, entire communities of algae and micro-organisms can flourish.

From the Siberian tundra

Nutrients can find their way into a melt pond in a variety of ways, For example, they can be washed in with waves of sea water; they can be transported by dust storms from the mainland (for example, from the Siberian tundra); or they can be washed with earth from the coast out on the ice, when it rains.

Finally, migratory birds or other larger animals resting on the ice can leave behind sources of nutrient.

• Climate change is accompanies by more storms and more precipitation, and we must expect that more nutrients will be released from the surroundings into the melt ponds. These conditions, plus the fact that the distribution of areas of melt ponds is increasing, can contribute to increased productivity in plant and animal life in the Arctic seas, says Professor Ronnie Glud of the Department of Biology at SDU.

Warmer and more windy

There are further factors that may potentially contribute to increased productivity in the Arctic seas:

• When the sea ice disappears, light can penetrate down into the water.
• water. When it gets warmer on the mainland, this creates more melt water, which can flow out into the sea, carrying nutrients in its wake.

BOX What the researchers did

Six melt ponds in Young Sound in North-Eastern Greenland were selected: two natural and four artificial basins. Phosphorous and nitrogen (nutrients, which are also known from common garden fertilizer) were added in various combinations to four ponds, while two served as control ponds. For a period of up to 13 days Heidi Louise Sørensen measured many different parameters in the melt water, including the content of Chlorophyll a: a pigment that enables algae to absorb energy from light. The chlorophyll content of the phosphorus- and nitrogen-enriched ponds was 2 to 10 times higher than in the control ponds and testifies to an increased content of algae.

BOX This is why the number of melt ponds is on the rise

Global warming is melting more and more sea ice, potentially forming an increasing number of melt ponds. NASA satellites have just measured the smallest ever distribution of sea ice in the Arctic. The melt ponds make the ice darker, so it absorbs, rather than reflects light and thereby it heats. This accelerates the melting process. Satellite photos show that areas with melt ponds are getting bigger each year.

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Larger doses of vitamin C may lead to a greater reduction in common cold duration

The relationship between vitamin C dosage and its effects on the duration of the common cold symptoms may extend to 6-8 grams per day.

Dozens of animal studies using different animal species have found that vitamin C significantly prevents and alleviates infections caused by diverse bacteria, viruses, and protozoa. Given the universal nature of the effect of vitamin C against various infections in different animal species, it also seems evident that vitamin C influences the susceptibility to, and the severity of infections in humans. However, the practical importance of vitamin C in human infections is not known.

The common cold is the most extensively studied infection regarding the effects of vitamin C. The majority of controlled trials have used a modest dosage of only 1 g per day of vitamin C. The pooled effect of all published studies has shown a statistically highly significant difference between the vitamin C and placebo groups, which indicates a genuine biological effect. However, the optimal doses and the maximal effects of vitamin C on the common cold are unknown. The trials that used doses higher than 1 g per day usually found greater effects than trials with exactly 1 g per day, which suggests a dose dependent effect. Nevertheless, definitive conclusions cannot be made from such a comparison because of numerous confounding differences between the trials. The most valid examination of dose-response is therefore within a single trial that has randomly selected trial groups with different vitamin C doses, so that exposure to viruses is similar and the outcome definition is identical in the study groups.

Dr. Harri Hemilä from the University of Helsinki, Finland, analyzed the findings of two randomized trials each of which investigated the effects of two vitamin C doses on the duration of the common cold. The first trial administered 3 g/day vitamin C to two study groups, 6 g/day to a third group, and the fourth group was administered a placebo. Compared with the placebo group the 6 g/day dose shortened colds by 17%, twice as much as the 3 g/day doses did. The second trial administered 4 g/day and 8 g/day vitamin C, and placebo to different groups, but only on the first day of the cold. Compared with the placebo group, the 8 g/day dose shortened colds by 19%, twice as much as the 4 g/day dose did. Both studies revealed a significant dose-response relationship between the vitamin C dosage and the duration of the common cold. The dose-response relationship in these two trials was also quite linear up to the levels of 6-8 g/day, thus it is possible that even higher doses may lead to still greater reductions in the duration of common cold. Dr. Hemilä notes that there have been proposals that vitamin C doses should be over 15 g/day for the best treatment of colds, but the highest doses that have so far been investigated in randomized trials have been much lower.

Dr. Hemilä concludes that "given the consistent effect of vitamin C on the duration of colds, and its safety and low cost, it would be worthwhile for individual common cold patients to test whether therapeutic 8 g/day vitamin C is beneficial for them. Self-dosing of vitamin C must be started as soon as possible after the onset of common cold symptoms to be most effective." Dr Hemilä also states that further therapeutic trials should be carried out to investigate the dose-response relation in the region of over 8 g/day of vitamin C.

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New dinosaur species sheds light on evolution, provides facial makeover for tyrannosaurs

An investigation by a team of scientists from Australia, Louisiana, Montana, New Mexico, and Wisconsin has identified and named a new species of the tyrannosaur clan: Daspletosaurus horneri -- "Horner's Frightful Lizard."

The species is named for renowned dinosaur paleontologist John "Jack" R. Horner, formerly curator at the Museum of the Rockies (MOR) in Bozeman, Montana. The tyrannosaur's name honors his discoveries of numerous dinosaur fossils and his mentorship of so many students that launched them to accomplished scientific careers. The type (name-bearing) specimens are stored in the research collections of the MOR.

The research is led by Thomas Carr, a professor in Carthage College's Biology Department and an expert on the evolution and growth of Tyrannosaurus rex and its closest relatives, collectively called tyrannosaurs.

The fossil resources of Montana, where the new tyrannosaur was found, are central to studies of dinosaur evolution, explains Professor David Varricchio of Montana State University: "These specimens emphasize the excellent record of dinosaurs to be found in Montana. They highlight both the quality of the specimens, the preservation revealing the details of how these giant carnivores once looked in life, as well as the overall collection of specimens that provides insight into the evolution of the tyrannosaur group. Montana remains a wonderful place to explore the Cretaceous."

In addition to adding a new species to the tyrannosaur family tree, the team's research provides new information about the mode of evolution and life appearance of tyrannosaurs -- specifically the face. This latest study, published today in Nature Publishing Group's Scientific Reports, found evidence for a rare, nonbranching type of evolution in tyrannosaurs and that tyrannosaurs had scaly, lipless faces and a highly touch-sensitive snout.

Carr said: "Daspletosaurus horneri was the youngest, and last, of its lineage that lived after its closest relative, D. torosus, which is found in Alberta, Canada. The close evolutionary relationship between the species taken with their geographic proximity and their sequential occurrence suggests that together they represent a single lineage that changed over geological time, where D. torosus has morphed into D. horneri."

Jason Moore, a professor in the Honors College at the University of New Mexico, elaborated: "One of the difficulties in demonstrating anagenetic change, as we suggest occurred in the Daspletosaurus lineage, is establishing that the different species in question don't overlap in time. The new radiometric dates we measured from the Two Medicine Formation not only help support that D. torosus and D. horneri did not live at the same time, but also help us refine the timeline of environmental and ecological changes recorded by the Two Medicine Formation."

Eric Roberts, a professor in geosciences with the College of Science and Engineering at James Cook University, explained: "Advances in radioisotopic dating of sedimentary deposits is key to testing this and many other evolutionary and ecological questions about dinosaurs and other ancient organisms. New age dates presented in this study are just the tip of the iceberg. Ongoing work in this field will provide unprecedented improvements in the dating of Late Cretaceous dinosaurs from western North America over the next few years."

Continued Carr, "When we consider the geological ages of the two species, the evolution of Daspletosaurus gives us an indication of how slowly evolution can act on large dinosaurs, which in this case happened over a span of 2.3 million years.

"This type of speciation is called anagenesis, which is different from the more common type called cladogensis, where an ancestral species splits into two or more descendant species. Although uncommon in many evolutionary studies, anagenesis has been reported in some duck- billed dinosaurs and horned dinosaurs. Daspletosaurus and these other dinosaurs point the way forward in picking out the evidence for anagenesis in the fossil record."

The team's work literally changes the face of tyrannosaurs, which they found was covered by a lipless "mask" of large flat scales and extensive patches of armor-like skin. This conclusion results from comparison of tyrannosaur skulls with those of crocodilians, birds, and mammals, and earlier work by other researchers who had matched bone texture with different types of skin covering.

Jayc Sedlmayr, a professor at the Louisiana State University Health Sciences Center New Orleans, explained, "Much of our research went beyond field paleontology: it was generated from lab based comparative anatomy, where you get arms deep in "blood and guts" dissecting birds as living dinosaurs and crocodilians as their closest living relatives and based on the similarities of the facial nerves and arteries we found in those same groups that left a trace on the bones, we were able to then reconstruct them in the new tyrannosaur species."

"It turns out that tyrannosaurs are identical to crocodilians in that the bones of their snouts and jaws are rough, except for a narrow band of smooth bone along the tooth row. In crocodilians, the rough texture occurs deep to large flat scales; given the identical texture, tyrannosaurs had the same covering," explained Carr. "We did not find any evidence for lips in tyrannosaurs: the rough texture covered by scales extends nearly to the tooth row, providing no space for lips.

"However, we did find evidence for other types of skin on the face, including areas of extremely coarse bone that supported armor-like skin on the snout and on the sides of the lower jaws. The armor-like skin would have protected tyrannosaurs from abrasions, perhaps sustained when hunting and feeding."

"Strikingly, the large horn behind the eye is elevated beyond the side of the head, indicating a covering of keratin, the hard and shiny material that makes up human fingernails," he continued.

In crocodilians and tyrannosaurs, the snout and jaws are penetrated by numerous small nerve openings, allowing hundreds of branches of the trigeminal nerve to innervate the skin, producing a sensitivity that, in crocodilians, is as sensitive as human fingertips. "Given that the foramina are identical in tyrannosaurs indicates that they had super-sensitive skin as well," explained Carr.

This sensitivity is part of a bigger evolutionary story, explained Sedlmayr. "Our findings of a complex sensory web is especially interesting because it is derived from the trigeminal nerve, which has an extraordinary evolutionary history of developing into wildly different 'sixth senses' in different vertebrates, such as sensing magnetic fields for bird migration, electroreception for predation in the platypus bill or the whisker pits of dolphins, sensing infrared in pit vipers to identify prey, guiding movements in mammals through the use of whiskers, sensing vibrations through the water by alligators, and turning the elephant trunk into a sensitive 'hand' similar to what has been done to the entire face of tyrannosaurs."

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New dinosaur species sheds light on evolution, provides facial makeover for tyrannosaurs

Bad cold? If you're lonely, it may feel worse

Suffering through a cold is annoying enough, but if you're lonely, you're likely to feel even worse, according to Rice University researchers.

A study led by Rice psychologist Chris Fagundes and graduate student Angie LeRoy indicated people who feel lonely are more prone to report that their cold symptoms are more severe than those who have stronger social networks.

"Loneliness puts people at risk for premature mortality and all kinds of other physical illnesses," LeRoy said. "But nothing had been done to look at an acute but temporary illness that we're all vulnerable to, like the common cold."

The study is the subject of a paper published this week in Health Psychology.

The researchers drew a distinction between feeling lonely and actual social isolation.

"This paper is about the quality of your relationships, not the quantity," LeRoy said. "You can be in a crowded room and feel lonely. That perception is what seems to be important when it comes to these cold symptoms."

Carrying out this task meant finding lonely people, isolating them -- and giving them a cold.

A total of 159 people age 18-55, nearly 60 percent of them men, were assessed for their psychological and physical health, given cold-inducing nasal drops and quarantined for five days in hotel rooms.

The participants, scored in advance on the Short Loneliness Scale and the Social Network Index, were monitored during and after the five-day stay. After adjusting for demographics like gender and age, the season, depressive affect and social isolation, the results showed those who felt lonely were no more likely to get a cold than those who weren't.

But those who were screened in advance for their level of loneliness and became infected -- not all of the participants did -- reported a greater severity of symptoms than those recorded in previous studies used as controls. The size of the participants' social networks appeared to have no bearing on how sick they felt.

"Previous research has shown that different psycho-social factors like feeling rejected or feeling left out or not having strong social bonds with other people do make people feel worse physically, mentally and emotionally," LeRoy said. "So we had that general framework to work with."

The effect may be the same for those under other kinds of stress, Fagundes said. "Anytime you have an illness, it's a stressor, and this phenomenon would probably occur," he said. "A predisposition, whether it's physical or mental, can be exaggerated by a subsequent stressor. In this case, the subsequent stressor is getting sick, but it could be the loss of a loved one, or getting breast cancer, which are subjects we also study.

"What makes this study so novel is the tight experimental design. It's all about a particular predisposition (loneliness) interacting with a particular stressor," he said.

"Doctors should take psychological factors into account at intake on a regular basis," Fagundes said. "It would definitely help them understand the phenomenon when the person comes in sick."

"We think this is important, particularly because of the economic burden associated with the common cold," LeRoy added. "Millions of people miss work each year because of it. And that has to do with how they feel, not necessarily with how much they're blowing their noses."

The findings are also an incentive to be more socially active, she said. "If you build those networks -- consistently working on them and your relationships -- when you do fall ill, it may not feel so bad."

Story Source:

Materials provided by Rice University. Original written by Mike Williams. Note: Content may be edited for style and length.

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Bad cold? If you're lonely, it may feel worse

Discovery of new predatory dinosaur species gives new insight on their evolution

Jayc Sedlmayr, PhD, Assistant Professor of Cell Biology & Anatomy at LSU Health Sciences Center New Orleans School of Medicine, was part of an international team of scientists who discovered a new tyrannosaur with an unusual mode of evolution. Their findings include that Daspletosaurus horneri, or "Horner's Frightful Lizard," evolved directly from its geologically older relative, D. torosus, a rare form of evolution called anagenesis where one species gradually morphs into a new one. The research also changes the face of tyrannosaurs, which the team concluded was covered by a lipless mask of large, flat scales, with smaller patches of armor-like skin and horn, as well as a highly touch-sensitive snout. The work is published online in Nature Research's Scientific Reports.

The team, led by Thomas Carr, PhD, of Carthage College's Department of Biology, also included Dr. David Varricchio of Montana State University, Dr. Eric Roberts of James Cook University and Dr. Jason Moore of the University of New Mexico. Dr. Carr is an expert on the evolution and growth of Tyrannosaurus rex and its closest relatives, collectively called tyrannosaurs.

LSU Health New Orleans' Dr. Jayc Sedlmayr, an evolutionary biologist whose research is in evolutionary anatomy, provided the biological non-boney anatomical perspective and interpretation. The team worked with excellently preserved fossils -- a skull and skeleton of a subadult, a skull and skeleton of an adult, a partial lower jaw of a subadult, and isolated bones of subadults and juveniles. The scientists compared tyrannosaur skulls with those of crocodylians, birds and mammals as well as earlier research that matched bone texture with different types of skin covering.

"Much of our research went beyond field paleontology -- it was generated from lab-based comparative anatomy, the dissection of birds as living dinosaurs and crocodilians as their closest living relatives, and based on the similarities of the facial nerves and arteries we found in those same groups which left a trace on the bone, we were able to then reconstruct in the new tyrannosaur species," notes LSU Health New Orleans anatomist Jayc Sedlmayr, PhD.

His own research was based on dissecting birds, alligators, crocodiles, lizards and turtles, including injecting their blood vessels and doing angiographic studies from some of their specimens. He then made hypotheses of homology (anatomical features that are shared because of a common ancestry) based on these dissections. If they had any boney traces (osteological correlates), he looked for those in fossil specimens. If a specific nerve or artery went through a particular opening or groove in a bone (foramen) in both birds and crocodiles, and this same foramen or groove is found in dinosaurs, he could then reconstruct that nerve or artery in the extinct animal -- and this is what the team did with the new species of tyrannosaur they described.

"Our findings of a complex sensory web is especially interesting because it is derived from the trigeminal nerve which has an extraordinary evolutionary history of developing into wildly different 'sixth senses' in different vertebrates -- sensing magnetic fields for bird migration, electroreception for predation in the platypus bill or the former whisker pits of dolphins, sensing infrared in pit vipers to identify prey, guiding mammals movements through the use of whiskers, sensing vibrations through the water by alligators, and turning the elephant trunk into a sensitive hand similar to what has been done to the entire face of tyrannosaurs," concludes Sedlmayr.

"It turns out that tyrannosaurs are identical to crocodylians in that the bones of their snouts and jaws are rough, except for a narrow band of smooth bone along the tooth row," says Carr. "In crocodylians, the rough texture occurs deep to large flat scales; given the identical texture, tyrannosaurs had the same covering. We did not find any evidence for lips in tyrannosaurs, the rough texture covered by scales extends nearly to the tooth row, providing no space for lips."

Daspletosaurus horneri lived in Montana 75.2-74.4 million years ago. With a body length of approximately 9 meters, this tyrannosaur had a wide snout, small orbital horns and slit-like pneumatic opening on the inside of the lacrimal bone. The large horn behind the eye is elevated beyond the side of the head, indicating a covering of keratin, the hard and shiny material that makes up human fingernails. Its prey were horned dinosaurs, crested duckbill dinosaurs, dome-headed dinosaurs and smaller theropod dinosaurs. It was the last species of Daspletosaurus ("frightful lizards") to have evolved in the American west.

"In some ways, the facial components of the trigeminal nerve of these dinosaurs mirrors that of humans," says Sedlmayr. "The human trigeminal nerve provides significant touch sensitivity to the face. It brings back sensation from our facial muscles allowing us to fine tune and coordinate the emotional and social displays so important to human communication. This nerve is so sensitive that in pathological conditions, trigeminal neuraligia, it can be responsible for some of the most severe pain our species can endure; in extreme cases, the pain is so great that many people suffering from it end up committing suicide. "

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Discovery of new predatory dinosaur species gives new insight on their evolution