Electronic plants createdSummary:Researchers have created analog and digital electronics circuits inside living plants. The scientists have used the vascular system of living roses to build key components of electronic circuits.Researchers at Linkping University in Sweden have created analog and digital electronics circuits inside living plants. The group at the Laboratory of Organic Electronics (LOE), under the leadership of Professor Magnus Berggren, have used the vascular system of living roses to build key components of electronic circuits.The article featured in the journalScience Advancesdemonstrates wires, digital logic, and even displays elements -- fabricated inside the plants -- that could develop new applications for organic electronics and new tools in plant science.Plants are complex organisms that rely on the transport of ionic signals and hormones to perform necessary functions. However, plants operate on a much slower time scale making interacting with and studying plants difficult. Augmenting plants with electronic functionality would make it possible to combine electric signals with the plant's own chemical processes. Controlling and interfacing with chemical pathways in plants could pave the way to photosynthesis-based fuel cells, sensors and growth regulators, and devices that modulate the internal functions of plants."Previously, we had no good tools for measuring the concentration of various molecules in living plants. Now we'll be able to influence the concentration of the various substances in the plant that regulate growth and development. Here, I see great possibilities for learning more," says Ove Nilsson, professor of plant reproduction biology and director of the Ume Plant Science Center, as well as a co-author of the article.The idea of putting electronics directly into trees for the paper industry originated in the 1990s while the LOE team at Linkping University was researching printed electronics on paper. Early efforts to introduce electronics in plants were attempted by Assistant Professor Daniel Simon, leader of the LOE's bioelectronics team, and Professor Xavier Crispin, leader of the LOE's solid-state device team, but a lack of funding from skeptical investors halted these projects.Thanks to independent research money from the Knut and Alice Wallenberg Foundation in 2012, Professor Berggren was able to assemble a team of researchers to reboot the project. The team tried many attempts of introducing conductive polymers through rose stems. Only one polymer, called PEDOT-S, synthesized by Dr. Roger Gabrielsson, successfully assembled itself inside the xylem channels as conducting wires, while still allowing the transport of water and nutrients. Dr. Eleni Stavrinidou used the material to create long (10 cm) wires in the xylem channels of the rose. By combining the wires with the electrolyte that surrounds these channels she was able to create an electrochemical transistor, a transistor that converts ionic signals to electronic output. Using the xylem transistors she also demonstrated digital logic gate function.Dr. Eliot Gomez used methods common in plant biology -- vacuum infiltration -- to infuse another PEDOT variant into the leaves. The infused polymer formed "pixels" of electrochemical cells partitioned by the veins. Applied voltage caused the polymer to interact with the ions in the leaf, subsequently changing the color of the PEDOT in a display-like device -- functioning similarly to the roll-printed displays manufactured at Acreo Swedish ICT in Norrkping.These results are early steps to merge the diverse fields of organic electronics and plant science. The aim is to develop applications for energy, environmental sustainability, and new ways of interacting with plants. Professor Berggren envisions the potential for an entirely new field of research:"As far as we know, there are no previously published research results regarding electronics produced in plants. No one's done this before," he says.Professor Berggren adds, "Now we can really start talking about 'power plants' -- we can place sensors in plants and use the energy formed in the chlorophyll, produce green antennas, or produce new materials. Everything occurs naturally, and we use the plants' own very advanced, unique systems."

Half of all Amazonian tree species may face extinctionSummary:Scientists report that more than half the tree species in the Amazonian rainforest may be globally threatened. However, the study also suggests that Amazonian parks, reserves, and indigenous territories, if properly managed, will protect most of the threatened species.More than half of all tree species in the world's most diverse forest--the Amazon--may be globally threatened, according to a new study.But the study also suggests that Amazonian parks, reserves, and indigenous territories, if properly managed, will protect most of the threatened species.The findings were announced by a research team comprising 158 researchers from 21 countries, led by Hans ter Steege of Naturalis Biodiversity Center in the Netherlands and Nigel Pitman of The Field Museum in Chicago, USA.The Field Museum was heavily involved with this study--the paper was co-authored by The Field Museum's Corine Vriesendorp and relied on data contributed by the Field's Robin Foster. Furthermore, some of the tree plot data was collected through the Museum's rapid inventory program, in which ecologists, biologists, and anthropologists travel to the Amazon and take stock of the plants, animals, and people who live there.Forest cover in the Amazon has been declining since the 1950s, but scientists still have a poor understanding of how this has affected populations of individual species.The new study, published this week in the journalScience Advances, compared data from forest surveys across the Amazon with maps of current and projected deforestation to estimate how many tree species have been lost, and where.The authors concluded that 36 to 57 percent of the Amazon's estimated 15,000 tree species likely qualify as globally threatened under IUCN Red List of Threatened Species criteria."We aren't saying that the situation in the Amazon has suddenly gotten worse for tree species," said Pitman. "We're just offering a new estimate of how tree species have been affected by historical deforestation, and how they'll be affected by forest loss in the future."Because the same trends observed in Amazonia apply throughout the tropics, the researchers argue that most of the world's more than 40,000 tropical tree species likely qualify as globally threatened.Fortunately, the authors report, protected areas and indigenous territories now cover over half of the Amazon Basin, and contain sizable populations of most threatened tree species."This is good news from the Amazon that you don't hear enough of," said ter Steege. "In recent decades Amazon countries have made major strides in expanding parks and strengthening indigenous land rights," he said. "And our study shows this has big benefits for biodiversity."However, parks and reserves will only prevent extinction of threatened species, the paper emphasizes, if they suffer no further degradation. The authors caution that Amazonian forests and reserves still face a barrage of threats, from dam construction and mining to wildfires and droughts intensified by global warming, and direct invasions of indigenous lands."It's a battle we're going to see play out in our lifetimes," said co-author William Laurance of James Cook University in Australia. "Either we stand up and protect these critical parks and indigenous reserves, or deforestation will erode them until we see large-scale extinctions."

Lasers could rapidly make materials hotter than the SunSummary:Lasers could heat materials to temperatures hotter than the centre of the Sun in only 20 quadrillionths of a second, according to new research.Lasers could heat materials to temperatures hotter than the centre of the Sun in only 20 quadrillionths of a second, according to new research.Theoretical physicists from Imperial College London have devised an extremely rapid heating mechanism that they believe could heat certain materials to ten million degrees in much less than a million millionth of a second.The method, proposed here for the first time, could be relevant to new avenues of research in thermonuclear fusion energy, where scientists are seeking to replicate the Sun's ability to produce clean energy.The heating would be about 100 times faster than rates currently seen in fusion experiments using the world's most energetic laser system at the Lawrence Livermore National Laboratory in California. The race is now on for fellow scientists to put the team's method into practice.Researchers have been using high-power lasers to heat material as part of the effort to create fusion energy for many years. In this new study, the physicists at Imperial were looking for ways to directly heat up ions -- particles which make up the bulk of matter.When lasers are used to heat most materials, the energy from the laser first heats up the electrons in the target. These in turn heat up the ions, making the process slower than targeting the ions directly.The Imperial team discovered that when a high-intensity laser is fired at a certain type of material, it will create an electrostatic shockwave that can heat ions directly. Their discovery is published today in the journalNature Communications."It's a completely unexpected result. One of the problems with fusion research has been getting the energy from the laser in the right place at the right time. This method puts energy straight into the ions," said the paper's lead author, Dr Arthur Turrell.Normally, laser-induced electrostatic shockwaves push ions ahead of them, causing them to accelerate away from the shockwave but not heat up. However, using sophisticated supercomputer modelling, the team discovered that if a material contains special combinations of ions, they will be accelerated by the shockwave at different speeds. This causes friction, which in turn causes them to rapidly heat. They found that the effect would be strongest in solids with two ion types, such as plastics."The two types of ions act like matches and a box; you need both," explained study co-author Dr Mark Sherlock from the Department of Physics at Imperial. "A bunch of matches will never light on their own -- you need the friction caused by striking them against the box.""That the actual material used as a target mattered so much was a surprise in itself," added study co-author Professor Steven Rose. "In materials with only one ion type, the effect completely disappears."The heating is so fast in part because the material targeted is so dense. The ions are squeezed together to almost ten times the usual density of a solid material as the electrostatic shockwave passes, causing the frictional effect to be much stronger than it would be in a less-dense material, such as a gas.The technique, if proven experimentally, could be the fastest heating rate ever demonstrated in a lab for a significant number of particles."Faster temperature changes happen when atoms smash together in accelerators like the Large Hadron Collider, but these collisions are between single pairs of particles," said Dr Turrell. "In contrast the proposed technique could be explored at many laser facilities around the world, and would heat material at solid density."

How does our brain form creative and original ideas?Summary:A new study attempted to crack the connection between brain activity and creativity. The results shed a new, perhaps unexpected light, on our ability to think outside the boxDeveloping an original and creative idea requires the simultaneous activation of two completely different networks in the brain: the associative -- "spontaneous" -- network alongside the more normative -- "conservative" -- network; this according to new research conducted at the University of Haifa.The researchers maintain that "creative thinking apparently requires 'checks and balances'." The new research was conducted as part of the doctoral dissertation of Dr. Naama Mayseless, and was supervised by Prof. Simone Shamay-Tsoory from the Department of Psychology at the University of Haifa in collaboration with Dr. Ayelet Eran from the Rambam Medical Center.According to the researchers, creativity is our ability to think in new and original ways to solve problems. But not every original solution is considered a creative one. If the idea is not fully applicable it is not considered creative, but simply one which is unreasonable.The researchers hypothesized that for a creative idea to be produced, the brain must activate a number of different -- and perhaps even contradictory -- networks. In the first part of the research, respondents were give half a minute to come up with a new, original and unexpected idea for the use of different objects. Answers which were provided infrequently received a high score for originality, while those given frequently received a low score. In the second part, respondents were asked to give, within half a minute, their best characteristic (and accepted) description of the objects. During the tests, all subjects were scanned using an FMRI device to examine their brain activity while providing the answer.The researchers found increased brain activity in an "associative" region among participants whose originality was high. This region, which includes the anterior medial brain areas, mainly works in the background when a person is not concentrating, similar to daydreaming.But the researchers found that this region did not operate alone when an original answer was given. For the answer to be original, an additional region worked in collaboration with the associative region -- the administrative control region. A more "conservative" region related to social norms and rules. The researchers also found that the stronger the connection, i.e., the better these regions work together in parallel -- the greater the level of originality of the answer."On the one hand, there is surely a need for a region that tosses out innovative ideas, but on the other hand there is also the need for one that will know to evaluate how applicable and reasonable these ideas are. The ability of the brain to operate these two regions in parallel is what results in creativity. It is possible that the most sublime creations of humanity were produced by people who had an especially strong connection between the two regions," the researchers concluded.

A new green power sourceSummary:To limit climate change, experts say that we need to reach carbon neutrality by the end of this century at the latest. To achieve that goal, our dependence on fossil fuels must be reversed. But what energy source will take its place? Researchers report that they just might have the answer: blue-green algae.As world leaders prepare to gather in France for the 2015 United Nations Conference on Climate Change next week, global warming -- and how to stop it -- is a hot topic.To limit climate change, experts say that we need to reach carbon neutrality by the end of this century at the latest. To achieve that goal, our dependence on fossil fuels must be reversed. But what energy source will take its place? Researchers from Concordia University in Montreal just might have the answer: blue-green algae.In a study published in the journalTechnology, a team led by Concordia engineering professor Muthukumaran Packirisamy describe their invention: a power cell that harnesses electrical energy from the photosynthesis and respiration of blue-green algae."Both photosynthesis and respiration ... involve electron transfer chains. By trapping the electrons released by blue-green algae during photosynthesis and respiration, we can harness the electrical energy they produce naturally," says Packirisamy.Why blue-green algae? Because it's everywhere.Also known as cyanobacteria, blue-green algae are the most prosperous microorganisms on earth, evolutionarily speaking. They occupy a broad range of habitats across all latitudes. And they've been here forever: the planet's early fauna and flora owe their makeup to cyanobacteria, which produced the oxygen that ultimately allowed higher life forms to flourish."By taking advantage of a process that is constantly occurring all over the world, we've created a new and scalable technology that could lead to cheaper ways of generating carbon-free energy," says Packirisamy.He notes that the invention is still in its early stages. "We have a lot of work to do in terms of scaling the power cell to make the project commercial."Currently, the photosynthetic power cell exists on a small scale, and consists of an anode, cathode and proton exchange membrane. The cyanobacteria or blue green algae are placed in the anode chamber.As they undergo photosynthesis, the cyanobacteria release electrons to the electrode surface. An external load is connected to the device to extract the electrons and harness power.As Packirisamy and his team develop and expand the project, he hopes that the micro photosynthetic power cells will soon be used in various applications, such as powering cell phones and computers. And maybe one day they'll power the world.

New 'self-healing' gel makes electronics more flexibleSummary:Researchers have developed a first-of-its-kind self-healing gel that repairs and connects electronic circuits, creating opportunities to advance the development of flexible electronics, biosensors and batteries as energy storage devices.Researchers in the Cockrell School of Engineering at The University of Texas at Austin have developed a first-of-its-kind self-healing gel that repairs and connects electronic circuits, creating opportunities to advance the development of flexible electronics, biosensors and batteries as energy storage devices.Although technology is moving toward lighter, flexible, foldable and rollable electronics, the existing circuits that power them are not built to flex freely and repeatedly self-repair cracks or breaks that can happen from normal wear and tear.Until now, self-healing materials have relied on application of external stimuli such as light or heat to activate repair. The UT Austin "supergel" material has high conductivity (the degree to which a material conducts electricity) and strong mechanical and electrical self-healing properties."In the last decade, the self-healing concept has been popularized by people working on different applications, but this is the first time it has been done without external stimuli," said mechanical engineering assistant professor Guihua Yu, who developed the gel. "There's no need for heat or light to fix the crack or break in a circuit or battery, which is often required by previously developed self-healing materials."Yu and his team created the self-healing gel by combining two gels: a self-assembling metal-ligand gel that provides self-healing properties and a polymer hydrogel that is a conductor. A paper on the synthesis of their hydrogel appears in the November issue ofNano Letters.In this latest paper, the researchers describe how they used a disc-shaped liquid crystal molecule to enhance the conductivity, biocompatibility and permeability of their polymer hydrogel. They were able to achieve about 10 times the conductivity of other polymer hydrogels used in bioelectronics and conventional rechargeable batteries. The nanostructures that make up the gel are the smallest structures capable of providing efficient charge and energy transport.In a separate paper published inNano Lettersin September, Yu introduced the self-healing hybrid gel. The second ingredient of the self-healing hybrid gel is a metal-ligand supramolecular gel. Using terpyridine molecules to create the framework and zinc atoms as a structural glue, the molecules form structures that are able to self-assemble, giving it the ability to automatically heal after a break.When the supramolecular gel is introduced into the polymer hydrogel, forming the hybrid gel, its mechanical strength and elasticity are enhanced.To construct the self-healing electronic circuit, Yu believes the self-healing gel would not replace the typical metal conductors that transport electricity, but it could be used as a soft joint, joining other parts of the circuit."This gel can be applied at the circuit's junction points because that's often where you see the breakage," he said. "One day, you could glue or paste the gel to these junctions so that the circuits could be more robust and harder to break."Yu's team is also looking into other applications, including medical applications and energy storage, where it holds tremendous potential to be used within batteries to better store electrical charge.Yu's research has received funding from the National Science Foundation, the American Chemical Society, the Welch Foundation and 3M.

It's a beauty: Quantum crystal is now more valuableSummary:Physicists have made their 'quantum crystal' of ultracold molecules more valuable than ever by packing about five times more molecules into it. The denser crystal will help scientists unlock the secrets of magnets and other, more exotic materials.Physicists at JILA have made their "quantum crystal" of ultracold molecules more valuable than ever by packing about five times more molecules into it. The denser crystal will help scientists unlock the secrets of magnets and other, more exotic materials.The crystal is actually a gas of particles trapped in 3-D formation by laser beams. The trap, called an optical lattice, has wells--local regions of low energy--like an egg carton made of light. The researchers maneuvered a single molecule into each well, successfully filling about 25 percent of the crystal. The structure has an advantage over a real crystal, as it is made of scientifically interesting molecules that normally would not crystallize.Described in the Nov. 6, 2015, issue ofScience,* the JILA crystal is useful for studying correlations among the molecules' "spins," or rotations, a quantum behavior related to magnetism. The denser crystal will enable scientists to study and model complex effects such as how spin correlations or entanglement--a quantum link between the properties of separated particles--spread through a large system. Scientists might use these effects, for example, to make novel materials for electronics or other applications.JILA is operated jointly by the National Institute of Standards and Technology (NIST) and the University of Colorado Boulder."The density in the crystal is now high enough to introduce long-range order, so the molecules behave as an interconnected system instead of just a collection of isolated particles," JILA/NIST Fellow Jun Ye says. "The molecules are close enough to each other for their spins to migrate and relocate to other molecules, allowing us to investigate quantum connections of many particles that may lead to new materials."Each molecule consists of one potassium atom bonded to one rubidium atom. The molecules are polar, with a positive electric charge on rubidium and a negative charge on potassium. This feature means the molecules can be controlled with electric fields and can interact strongly, even when far apart."Because our molecules are polar, neighboring molecules in the lattice will interact with each other," JILA/NIST Fellow Deborah Jin says. "When each molecule has multiple neighbors to talk to, these interactions become much more important and affect the entire crystal."Building the quantum crystal was something of a tour de force in atomic manipulation. While researchers can create a crystal from one atomic gas relatively easily, combining two different atomic gases was difficult. But this was necessary to arrange for the two different atoms to form a molecule. The recipe required a small cloud of rubidium atoms, a class of particles that like to act in unison, and a large cloud of potassium atoms, which tend to be more independent.The JILA team loaded the optical lattice by overlapping the two clouds to match their densities and energy levels in the intersection so that one of each type of atom tended to accumulate in each well. Researchers then used magnetic fields and lasers to fuse the atom pairs into molecules with the lowest possible vibrational and rotational energy. Remaining stray atoms were flushed out of the trap.JILA scientists first created ultracold molecules in 2008 and several years ago formed the first molecular crystal, in which the molecules swapped spins. To reduce chemical reactions and extend molecule lifetimes, researchers made the trap wells deeper. Now they've achieved their next goal of filling enough wells to unify the crystal as a system, opening the door for intriguing new quantum phenomena.The research was funded by NIST, the Air Force Office of Scientific Research, Army Research Office and National Science Foundation.As a non-regulatory agency of the U.S. Department of Commerce, NIST promotes U.S. innovation and industrial competitiveness by advancing measurement science, standards and technology in ways that enhance economic security and improve our quality of life.

Flexo-electric nanomaterial createdSummary:Researchers have developed a 'flexo-electric' nanomaterial. The material has built-in mechanical tension that changes shape when you apply electrical voltage, or that generates electricity if you change its shape. The researchers also show that the thinner you make the material, the stronger this flexo-electric effect becomes. Researchers describe this as a completely new field of knowledge with some interesting applications. You could use the material to recharge a pacemaker inside the human body, for example, or to make highly sensitive sensors.Researchers at the University of Twente's MESA+ research institute, together with researchers from several other institutions, have developed a 'flexo-electric' nanomaterial. The material has built-in mechanical tension that changes shape when you apply electrical voltage, or that generates electricity if you change its shape. In an article published in the leading scientific journal Nature Nanotechnology, the researchers also show that the thinner you make the material, the stronger this flexo-electric effect becomes. Professor Guus Rijnders, who was involved in the research, describes this as a completely new field of knowledge with some interesting applications. You could use the material to recharge a pacemaker inside the human body, for example, or to make highly sensitive sensors.Piezoelectric materials are widely used in electronic applications. In specific terms, these are crystalline materials that can convert electrical power into pressure and vice versa. The disadvantage of these materials is that they contain lead -- which has environmental and health risks -- and that the piezoelectric effect decreases when you make the material thinner.The thinner the material, the stronger the effectEver since the 1960s physicists have been arguing that the flexo-electric effect could exist. This would enable non-piezoelectric materials to be given piezoelectric properties. At that time, however, manufacturing methods were inadequate for the production of such materials. Now, researchers from the University of Twente, the Catalan Institute of Nanoscience and Nanotechnology and Cornell University have succeeded in developing a flexo-electric nano system just 70 nanometres thick. It turns out that even though the flexo-electric effect is very weak, the thinner you make the material, the stronger the effect becomes.Ultrasensitive sensorsAccording to Professor Guus Rijnders, who was involved in the research, it will eventually be possible to create flexo-electric materials with a thickness of just a few atomic layers. This discovery could have all kinds of interesting applications. 'You could make sensors that can detect a single molecule, for example. A molecule would land on a vibrating sensor, making it just fractionally heavier, slowing the vibration just slightly. The reduction in frequency could then easily be measured using the flexo-electric effect.' In addition to ultra-sensitive sensors, flexo-electric materials could also be useful in applications that require a limited amount of power, but which are difficult to reach, such as in pacemakers or cochlear implants inside the human body.

Hydra can modify its genetic programCertain cells of the animal change to overcome the loss of its nervous systemummary:Champion of regeneration, Hydra is capable of reforming a complete individual from any fragment of its body. It is even able to remain alive when all its neurons have disappeared. Researchers have discovered how: cells of the epithelial type modify their genetic program by overexpressing a series of genes, among which some are involved in diverse nervous functions.Champion of regeneration, the freshwater polyp Hydra is capable of reforming a complete individual from any fragment of its body. It is even able to remain alive when all its neurons have disappeared. Researcher the University of Geneva (UNIGE), Switzerland, have discovered how: cells of the epithelial type modify their genetic program by overexpressing a series of genes, among which some are involved in diverse nervous functions. Studying Hydra cellular plasticity may thus influence research in the context of neurodegenerative diseases. The results are published inPhilosophical Transactions of the Royal Society.The freshwater Hydra is endowed with an extraordinary power of regeneration, discovered by the Swiss naturalist Abraham Trembley more than 250 years ago. The group of Brigitte Galliot, professor at the Department of Genetics and Evolution of the Faculty of Science of UNIGE, has studied the stem cells functioning and cellular plasticity of the polyp: "its nervous system regulates in particular contraction bursts, feeding behavior, moving or swimming. If the stem cells responsible for its renewal are depleted, the Hydra can still develop, even when all its neurons have disappeared. We wanted to understand how this is possible."Enhancing other cells' sensing abilityThe researchers compared gene expression at various positions along the body axis in polyps devoid or not of their nervous stem cells. They observed a modification of the genetic program in animals depleted of these cells: "we identified 25 overexpressed genes in epithelial cells, the cells forming the Hydra's coating tissues. Some of these genes are involved in diverse nervous functions, such as neurogenesis or neurotransmission," says Yvan Wenger, co-first author of the article."Epithelial cells do not possess typical neuronal functions. However, Hydra's loss of neurogenesis induces epithelial cells to modify their genetic program accordingly, indicating that they are ready to assume some of these functions. These "naturally" genetically modified epithelial cells are thus likely to enhance their sensitivity and response to environmental signals, to partially compensate for the lack of nervous system," explains Wanda Buzgariu, co-first author of the article. The detail of these new functions remains to be discovered, as well as how epithelial cells proceed to overexpress these genes and thus adapt their genetic program.Cellular plasticity maintains youthStudying Hydra's cellular plasticity may be relevant in the context of neurodegenerative diseases. Indeed, some of the genes identified in this animal play an important role in cellular reprogramming or in neurogenesis in mammals. The researchers therefore wonder: would it be possible to restore sensing or secretion functions from other cell types, when some neurons degenerate?This study also allows to go back to the origins of nervous systems. Epithelial cells most probably preceded nerve cells, performing some of their functions, although in a much slower way. "The loss of neurogenesis in Hydra may provide an opportunity to observe a reverse evolutive process, because it sheds light on a repressed ancestral genetic toolkit. An atavism of epithelial cells, when they most probably also possessed proto-neuronal functions," concludes Brigitte Galliot.

Ants filmed building moving bridges from their live bodiesApplications for robots in disaster relief, deep sea explorationSummary:Army ants build living bridges by linking their bodies to span gaps and create shortcuts across rainforests in Central and South America. An international team of researchers has now discovered these bridges can move from their original building point to span large gaps and change position as required.Army ants build living bridges by linking their bodies to span gaps and create shortcuts across rainforests in Central and South America. An international team of researchers has now discovered these bridges can move from their original building point to span large gaps and change position as required.The bridges stop moving when they become so long that the increasing costs incurred by locking workers into the structure outweigh the benefit that the colony gains from further shortening their trail. Bridges dismantle when the ants in the structure sense the traffic walking over them slows down below a critical threshold.Co-lead author Dr Christopher Reid, a postdoctoral researcher at the University of Sydney's Insect Behaviour and Ecology Lab and formerly with the New Jersey Institute of Technology, said the findings could be applied to develop swarm robotics for exploration and rescue operations. By analysing how ants optimise utility, researchers may be able to create simple control algorithms to allow swarms of robots to behave in similar ways to an ant colony.The paper, 'Army ants dynamically adjust living bridges in response to a cost-benefit trade-off', is being published in the journalProceedings of the National Academy of Sciences(PNAS).The team of researchers -- from the Max Planck Institute for Ornithology (Konstanz, Germany), University of Konstanz, and the United States's New Jersey Institute of Technology, Princeton University and George Washington University -- found the bridges can assemble and disassemble in seconds. They can also change their position in response to the immediate environment.The dynamic nature of the bridges has been found to facilitate travel by the colony at maximum speed, across unknown and potentially dangerous terrains. Prior to the study it was assumed that, once they had been built, the bridges were relatively static structures."Indeed, after starting at intersections between twigs or lianas travelled by the ants, the bridges slowly move away from their starting point, creating shortcuts and progressively lengthening by addition of new workers, before stopping, suspended in mid-air," said Dr Reid."In many cases, the ants could have created better shortcuts, but instead they ceased moving their bridges before achieving the shortest route possible."The researchers discovered that, although ants benefitted from shorter travelling distances because of their bridges, they also incurred a cost by sequestering workers that could be used for other important tasks. When building their bridges, army ants had to balance this cost-benefit trade-off.Dr Reid said the findings had implications for other self-assembling systems, such as reconfigurable materials and autonomous robotic swarms. "Artificial systems made of independent robots operating via the same principles as the army ants could build large-scale structures as needed," Dr Reid said."Such swarms could accomplish remarkable tasks, such as creating bridges to navigate complex terrain, plugs to repair structural breaches, or supports to stabilise a failing structure."These systems could also enable robots to operate in complex unpredictable settings, such as in natural disaster areas, where human presence is dangerous or problematic."

Whiffs from cyanobacteria likely responsible for Earth's oxygenEarth's oxygen-rich atmosphere emerged in whiffs from a kind of cyanobacteria in shallow oceans around 2.5 billion years ago, according to new research from Canadian and US scientists.These whiffs of oxygen likely happened in the following 100 million years, changing the levels of oxygen in Earth's atmosphere until enough accumulated to create a permanently oxygenated atmosphere around 2.4 billion years ago -- a transition widely known as the Great Oxidation Event."The onset of Earth's surface oxygenation was likely a complex process characterized by multiple whiffs of oxygen until a tipping point was crossed," said Brian Kendall, a professor of Earth and Environmental Sciences at the University of Waterloo. "Until now, we haven't been able to tell whether oxygen concentrations 2.5 billion years ago were stable or not. These new data provide a much more conclusive answer to that question."The findings are presented in a paper published this month inScience Advancesfrom researchers at Waterloo, University of Alberta, Arizona State University, University of California Riverside, and Georgia Institute of Technology. The team presents new isotopic data showing that a burst of oxygen production by photosynthetic cyanobacteria temporarily increased oxygen concentrations in Earth's atmosphere."One of the questions we ask is: 'did the evolution of photosynthesis lead directly to an oxygen-rich atmosphere? Or did the transition to today's world happen in fits and starts?" said Professor Ariel Anbar of Arizona State University. "How and why Earth developed an oxygenated atmosphere is one of the most profound puzzles in understanding the history of our planet."The new data supports a hypothesis proposed by Anbar and his team in 2007. In Western Australia, they found preliminary evidence of these oxygen whiffs in black shales deposited on the seafloor of an ancient ocean.The black shales contained high concentrations of the elements molybdenum and rhenium, long before the Great Oxidation Event.These elements are found in land-based sulphide minerals, which are particularly sensitive to the presence of atmospheric oxygen. Once these minerals react with oxygen, the molybdenum and rhenium are released into rivers and eventually end up deposited on the sea floor.In the new paper, researchers analyzed the same black shales for the relative abundance of an additional element: osmium. Like molybdenum and rhenium, osmium is also present in continental sulfide minerals. The ratio of two osmium isotopes --187Os to188Os -- can tell us if the source of osmium was continental sulfide minerals or underwater volcanoes in the deep ocean.The osmium isotope evidence found in black shales correlates with higher continental weathering as a result of oxygen in the atmosphere. By comparison, slightly younger deposits with lower molybdenum and rhenium concentrations had osmium isotope evidence for less continental input, indicating the oxygen in the atmosphere had disappeared.The paper's authors also include Professor Robert Creaser of the University of Alberta, Professor Timothy Lyons from the University of California Riverside and Professor Chris Reinhard from the Georgia Institute of Technology.

Ghostly and beautiful: 'Planetary nebulae' get more meaningful physical presenceA way of estimating more accurate distances to the thousands of so-called planetary nebulae dispersed across our Galaxy has been announced by a team of three astronomers based at the University of Hong Kong: Dr David Frew, Prof Quentin Parker and Dr Ivan Bojicic. The scientists publish their results inMonthly Notices of the Royal Astronomical Society.Despite their name, planetary nebulae have nothing to do with planets. They were described as such by early astronomers whose telescopes showed them as glowing disc-like objects.We now know that planetary nebulae are actually the final stage of activity of stars like our Sun. When they reach the end of their lives, these stars eject most of their atmosphere into space, leaving behind a hot dense core. Light from this core causes the expanding cloud of gas to glow in different colours as it slowly grows, fading away over tens of thousands of years.There are thousands of planetary nebulae in our Galaxy alone, and they provide targets for professional and amateur astronomers alike, with the latter often taking spectacular images of these beautiful objects. But despite intense study, scientists have struggled to measure one of their key properties -- their distance.Dr Frew, lead author on the paper, said: "For many decades, measuring distances to Galactic planetary nebulae has been a serious, almost intractable problem because of the extremely diverse nature of the nebulae themselves and their central stars. But finding those distances is crucial if we want to understand their true nature and physical properties."The solution presented by the astronomers is both simple and elegant. Their method requires only an estimate of the dimming toward the object (caused by intervening interstellar gas and dust), the projected size of the object on the sky (taken from the latest high resolution surveys) and a measurement of how bright the object is (as obtained from the best modern imaging).The resulting so-called 'surface-brightness relation' has been robustly calibrated using more than 300 planetary nebulae whose accurate distances have been determined via independent and reliable means. Prof Parker explained that, "the basic technique is not new but what marks out this work from what has gone before is the use of the most up-to-date and reliable measurements of all three of those crucial properties."This is combined with the use of the authors' own robust techniques to effectively remove "doppelgangers" and mimics that have seriously contaminated previous planetary nebulae catalogues and added considerable errors to other distance measurements.The new approach works over a factor of several hundred thousand in surface brightness, and allows astronomers to measure the distances to planetary nebulae up to 5 times more accurately than previous methods. "Our new scale is the first to accurately determine distances for the very faintest planetaries" said Dr Frew. "Since the largest nebulae are the most common, getting their distances right is a crucial step."Planetary nebulae are a fascinating if brief stage in the life of a low- to middle-weight star. Being able to better measure distances and hence the sizes of these objects will give scientists a far better insight into how these objects form and develop, and how stars as a whole evolve and die.

New vision for multifunctional materialsThe protective shell of a sea-dwelling chiton paves the way towards new materials that combine different functionsMultifunctional materials with sensory capabilities like those of vision, touch or even smell could profoundly expand the possibilities of industrial design in many areas. Taking a cue from nature, a cross-institutional collaboration involving researchers from the Wyss Institute for Biologically Inspired Engineering at Harvard University and MIT has deciphered how the biomineral making up the body armor of a chiton mollusk has evolved to create functional eyes embedded in the animal's protective shell. The findings could help determine so far still elusive rules for generating human-made multifunctional materials and are reported in the November 20 issue ofScience.Multifunctional materials that can sense physical stimuli in their environments could enable us to build houses that make use of their environments, to constantly monitor wear-and-tear and look for signs of damage in materials or even to better deliver some drugs and produce bioengineered organs."To date, artificial materials that have the ability to perform multiple and often structurally opposite functions are not available. We can not yet rationally design them but studying different multifunctional biomaterials present in nature should ultimately allow us to deduct the key principles for this relatively new area of materials science," said Joanna Aizenberg, Ph.D., who is a Core Faculty member at the Wyss Institute, leader of the Wyss Adaptive Material Technologies platform, and also is the Amy Smith Berylson Professor of Materials Science at Harvard's John A. Paulsen School of Engineering and Applied Sciences (SEAS). Early work by Aizenberg on a sea-dwelling brittlestar that uses the same mineralized material to grow both a skeleton and visual organs had set the stage for the exploration into multifunctional biomaterials.Now, inspired by previous biological research performed by Daniel Speiser, Ph.D., Aizenberg and Christine Ortiz, Ph.D., the Morris Cohen Professor of Materials Science and Engineering at MIT, formed a multi-disciplinary team to study another tell tale example offered by nature: the outer protective shell of the chiton Acanthopleura granulata, a tropical sea water mollusk, that is endowed with hundreds of tiny eyes. Speiser is a Professor at the University of South Carolina who joined the Harvard/MIT-led effort.Most eyes in nature are made of organic molecules. In contrast, the chiton's eyes are inorganic and made of the same crystalline mineral called aragonite that also assembles the body armor. They enable the chiton to perceive changes in light and thus to respond to approaching predators by tightening their grip to surfaces under water.Using a suite of highly resolving microscopic and crystallographic techniques, the team unraveled the 3-dimensional architecture and geometry of the eyes, complete with an outer cornea, a lens and an underlying chamber that houses the photoreceptive cells necessary to feed focused images to the chiton's nervous system. Importantly, the researchers found that aragonite crystals in the lens are larger than in the shell and organized into more regular alignments that allow light to be gathered and bundled."By studying isolated eyes, we identified how exactly the lens material generates a defined focal point within the chamber which, like a retina, can render images of objects such as predatory fish," said Ling Li, a postdoctoral fellow working with Aizenberg and a co-first author of the study."We also learned that optical performance was developed as a second function to the otherwise protective shell with mutual trade-offs in both functionalities. The material properties that are favored for optical performance are usually not favored for mechanical robustness so that the evolving chiton had to balance out its mechanical vulnerabilities by limiting the size of the eyes and placing them in regions protected by strong protrusions," said Li."The investigation of Nature's finest "multitasking artists" can provide insight into functional synergies and trade-offs in multifunctional materials and guide us in other studies toward the development of revolutionary biomimetic materials. We thus are probably one step closer to construct houses made of a material that is not only mechanically robust, but also furnished with lenses capable of flexibly regulating light and temperature inside and sense environmental conditions," said Aizenberg."This study shows just how amazing nature is at solving complex problems in simple and elegant ways. By uncovering the design rules that this simple organism uses to self-assemble a multi-functional shell that simultaneously provides physical protection from the environment and an eye that can sense oncoming invaders, the team is now in a position to leverage these insights to engineer synthetic materials that could lead to entirely new solutions for both industrial and medical applications," said Wyss Institute Founding Director Don Ingber, M.D., Ph.D., who also is the Judah Folkman Professor of Vascular Biology at Harvard Medical School and Boston Children's Hospital, and Professor of Bioengineering at SEAS.The research team used the 2-BM beamline at the Advanced Photon Source (APS), a U.S. Department of Energy (DOE) Office of Science User Facility located at Argonne National Laboratory, to conduct high-resolution X-ray micro-tomography towards determining the 3-D morphology of the sensory structure in the shell of chitons.