Temperature fluctuations: Atlantic Ocean dances with the sun and volcanoes

Natural fluctuations in the ocean temperature in the North Atlantic have a significant impact on the climate in the northern hemisphere. These fluctuations are the result of a complex dance between the forces of nature, but researchers at Aarhus University can now show that solar activity and the impact of volcanic eruptions have led this dance during the last two centuries.Imagine a ballroom in which two dancers apparently keep in time to their own individual rhythm. The two partners suddenly find themselves moving to the same rhythm and, after a closer look, it is clear to see which one is leading.It was an image like this that researchers at Aarhus University were able to see when they compared studies of solar energy release and volcanic activity during the last 450 years, with reconstructions of ocean temperature fluctuations during the same period.The results actually showed that during the last approximately 250 years — since the period known as the Little Ice Age — a clear correlation can be seen where the external forces, i.e. the Sun’s energy cycle and the impact of volcanic eruptions, are accompanied by a corresponding temperature fluctuation with a time lag of about five years.In the previous two centuries, i.e. during the Little Ice Age, the link was not as strong, and the temperature of the Atlantic Ocean appears to have followed its own rhythm to a greater extent.The results were recently published in the scientific journal Nature Communications.In addition to filling in yet another piece of the puzzle associated with understanding the complex interaction of the natural forces that control the climate, the Danish researchers paved the way for linking the two competing interpretations of the origin of the oscillation phenomenon.Temperature fluctuations discovered around the turn of the millenniumThe climate is defined on the basis of data including mean temperature values recorded over a period of thirty years. Northern Europe thus has a warm and humid climate compared with other regions on the same latitudes. This is due to the North Atlantic Drift (often referred to as the Gulf Stream), an ocean current that transports relatively warm water from the south-west part of the North Atlantic to the sea off the coast of Northern Europe.Around the turn of the millennium, however, climate researchers became aware that the average temperature of the Atlantic Ocean was not entirely stable, but actually fluctuated at the same rate throughout the North Atlantic. This phenomenon is called the Atlantic Multidecadal Oscillation (AMO), which consists of relatively warm periods lasting thirty to forty years being replaced by cool periods of the same duration. The researchers were able to read small systematic variations in the water temperature in the North Atlantic in measurements taken by ships during the last 140 years.Although the temperature fluctuations are small — less than 1C — there is a general consensus among climate researchers that the AMO phenomenon has had a major impact on the climate in the area around the North Atlantic for thousands of years, but until now there has been doubt about what could cause this slow rhythm in the temperature of the Atlantic Ocean. One model explains the phenomenon as internal variability in the ocean circulation — somewhat like a bathtub sloshing water around in its own rhythm. …

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Earth’s dynamic interior: Multiple compositional components of Earth’s deep mantle carried up to surface

Seeking to better understand the composition of the lowermost part of Earth’s mantle, located nearly 2,900 kilometers (1,800 miles) below the surface, a team of Arizona State University researchers has developed new simulations that depict the dynamics of deep Earth. A paper published March 30 in Nature Geoscience reports the team’s findings, which could be used to explain the complex geochemistry of lava from hotspots such as Hawaii.Mantle convection is the driving force behind continental drift and causes earthquakes and volcanoes on the surface. Through mantle convection, material from the lowermost part of Earth’s mantle could be carried up to the surface, which offers insight into the composition of the deep Earth. Earth’s core is very hot (~4000 K) and rocks at the core mantle boundary are heated and expand to have a lower density. These hot rocks (also called mantle plumes) could migrate to the surface because of buoyancy.Observations, modeling and predictions have indicated that the deepest mantle is compositionally complex and continuously churning and changing.”The complex chemical signatures of hotspot basalts provide evidence that the composition of the lowermost part of Earth’s mantle is different from other parts. The main question driving this research is how mantle plumes and different compositional components in Earth’s mantle interact with each other, and how that interaction leads to the complex chemistry of hotspot basalts. The answer to this question is very important for us to understand the nature of mantle convection,” explains lead author Mingming Li, who is pursuing his Ph.D. in geological sciences.”Obviously, we cannot go inside of Earth to see what is happening there. However, the process of mantle convection should comply with fundamental physics laws, such as conservation of mass, momentum and energy. What we have done is to simulate the process of mantle convection by solving the equations which controls the process of mantle convection,” says Li.It has long been suggested that Earth’s mantle contains several different compositional reservoirs, including an ancient more-primitive reservoir at the lowermost mantle, recycled oceanic crust and depleted background mantle. …

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Northern and southern hemisphere climates follow the beat of different drummers

Over the last 1000 years, temperature differences between the Northern and Southern Hemispheres were larger than previously thought. Using new data from the Southern Hemisphere, researchers have shown that climate model simulations overestimate the links between the climate variations across Earth with implications for regional predictions.These findings are demonstrated in a new international study coordinated by Raphael Neukom from the Oeschger Centre of the University of Bern and the Swiss Federal Research Institute WSL and are published today in the journal Nature Climate Change.The Southern Hemisphere is a challenging place for climate scientists. Its vast oceans, Antarctic ice, and deserts make it particularly difficult to collect information about present climate and, even more so, about past climate. However, multi-centennial reconstructions of past climate from so-called proxy archives such as tree-rings, lake sediments, corals, and ice-cores are required to understand the mechanisms of the climate system. Until now, these long-term estimates were almost entirely based on data from the Northern Hemisphere.Over the past few years, an international research team has made a coordinated effort to develop and analyse new records that provide clues about climate variation across the Southern Hemisphere. Climate scientists from Australia, Antarctic-experts, as well as data specialists and climate modellers from South and North America and Europe participated in the project. They compiled climate data from over 300 different locations and applied a range of methods to estimate Southern Hemisphere temperatures over the past 1000 years. In 99.7 percent of the results, the warmest decade of the millennium occurs after 1970.Surprisingly, only twice over the entire last millennium have both hemispheres simultaneously shown extreme temperatures. One of these occasions was a global cold period in the 17th century; the other one was the current warming phase, with uninterrupted global warm extremes since the 1970s. “The ‘Medieval Warm Period’, as identified in some European chronicles, was a regional phenomenon,” says Raphael Neukom. …

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Inspiration linked to bipolar disorder risk

Inspiration has been linked with people at risk of developing bipolar disorder for the first time in a study led by Lancaster University.For generations, artists, musicians, poets and writers have described personal experiences of mania and depression, highlighting the unique association between creativity and bipolar disorder — experiences which are backed up by recent research. But, until now, the specific links between inspiration — the generation of ideas that form the basis of creative work — and bipolar disorder has received little attention.New research by Professor by Steven Jones and Dr Alyson Dodd, of Lancaster University, and Dr June Gruber at Yale University, has shown people at higher risk for developing bipolar disorder consistently report stronger experiences of inspiration than those at lower risk.The paper ‘Development and Validation of a New Multidimensional Measure of Inspiration: Associations with Risk for Bipolar Disorder’, published in PLOS One this week, found a specific link between those people who found their source of inspiration within themselves and risk for bipolar disorder.Professor Jones, co-director of Lancaster University’s Spectrum Centre, said: “It appears that the types of inspiration most related to bipolar vulnerability are those which are self-generated and linked with strong drive for success.”Understanding more about inspiration is important because it is a key aspect of creativity which is highly associated with mental health problems, in particular bipolar disorder. People with bipolar disorder highly value creativity as a positive aspect of their condition. This is relevant to clinicians, as people with bipolar disorder may be unwilling to engage with treatments and therapies which compromise their creativity.”As part of the study, 835 undergraduate students were recruited to complete online questionnaires from both Yale University in the U.S. and Lancaster University in the U.K.They were asked to complete a questionaire which measured their bipolar risk using a widely-used and well-validated 48-item measure which captures episodic shifts in emotion, behaviour, and energy called The Hypomanic Personality Scale (HPS).They also completed a new questionnaire developed by the team which was designed to explore beliefs about inspiration, in particular the sources of inspiration — whether individuals thought it came from within themselves, from others or the wider environment. This measure was called the the EISI (External and Internal Sources of Inspiration) measure.The students who scored highly for a risk of bipolar also consistently scored more highly than the others for levels of inspiration and for inspiration which they judged to have come from themselves.Researchers say, although this pattern was consistent, the effect sizes were relatively modest so, although inspiration and bipolar risk are linked, it is important to explore other variables to get a fuller picture and to conduct further research with individuals with a clinical diagnosis of bipolar disorder.The research team is currently inviting UK-based individuals with a diagnosis of bipolar disorder to take part in an online survey exploring associations between inspiration, mood and recovery. Go to: www.thinkingstyle.spectrumdevelopment.org.uk.Story Source:The above story is based on materials provided by Lancaster University. Note: Materials may be edited for content and length.

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Four in 10 infants lack strong parental attachments

In a study of 14,000 U.S. children, 40 percent lack strong emotional bonds — what psychologists call “secure attachment” — with their parents that are crucial to success later in life, according to a new report. The researchers found that these children are more likely to face educational and behavioral problems.In a report published by Sutton Trust, a London-based institute that has published more than 140 research papers on education and social mobility, researchers from Princeton University, Columbia University, the London School of Economics and Political Science and the University of Bristol found that infants under the age of three who do not form strong bonds with their mothers or fathers are more likely to be aggressive, defiant and hyperactive as adults. These bonds, or secure attachments, are formed through early parental care, such as picking up a child when he or she cries or holding and reassuring a child.”When parents tune in to and respond to their children’s needs and are a dependable source of comfort, those children learn how to manage their own feeling and behaviors,” said Sophie Moullin, a joint doctoral candidate studying at Princeton’s Department of Sociology and the Office of Population Research, which is based at the Woodrow Wilson School of Public and International Affairs. “These secure attachments to their mothers and fathers provide these children with a base from which they can thrive.”Written by Moullin, Jane Waldfogel from Columbia University and the London School of Economics and Political Science and Elizabeth Washbrook from the University of Bristol, the report uses data collected by the Early Childhood Longitudinal Study, a nationally representative U.S. study of 14,000 children born in 2001. The researchers also reviewed more than 100 academic studies.Their analysis shows that about 60 percent of children develop strong attachments to their parents, which are formed through simple actions, such as holding a baby lovingly and responding to the baby’s needs. Such actions support children’s social and emotional development, which, in turn, strengthens their cognitive development, the researchers write. These children are more likely to be resilient to poverty, family instability, parental stress and depression. Additionally, if boys growing up in poverty have strong parental attachments, they are two and a half times less likely to display behavior problems at school.The approximately 40 percent who lack secure attachments, on the other hand, are more likely to have poorer language and behavior before entering school. …

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Rainbow-catching waveguide could revolutionize energy technologies

By slowing and absorbing certain wavelengths of light, engineers open new possibilities in solar power, thermal energy recycling and stealth technologyMore efficient photovoltaic cells. Improved radar and stealth technology. A new way to recycle waste heat generated by machines into energy.All may be possible due to breakthrough photonics research at the University at Buffalo.The work, published March 28 in the journal Scientific Reports, explores the use of a nanoscale microchip component called a “multilayered waveguide taper array” that improves the chip’s ability to trap and absorb light.Unlike current chips, the waveguide tapers (the thimble-shaped structures pictured above) slow and ultimately absorb each frequency of light at different places vertically to catch a “rainbow” of wavelengths, or broadband light.”We previously predicted the multilayered waveguide tapers would more efficiently absorb light, and now we’ve proved it with these experiments,” says lead researcher Qiaoqiang Gan, PhD, UB assistant professor of electrical engineering. “This advancement could prove invaluable for thin-film solar technology, as well as recycling waste thermal energy that is a byproduct of industry and everyday electronic devices such as smartphones and laptops.”Each multilayered waveguide taper is made of ultrathin layers of metal, semiconductors and/or insulators. The tapers absorb light in metal dielectric layer pairs, the so-called hyperbolic metamaterial. By adjusting the thickness of the layers and other geometric parameters, the tapers can be tuned to different frequencies including visible, near-infrared, mid-infrared, terahertz and microwaves.The structure could lead to advancements in an array of fields.For example, there is a relatively new field of advanced computing research called on-chip optical communication. In this field, there is a phenomenon known as crosstalk, in which an optical signal transmitted on one waveguide channel creates an undesired scattering or coupling effect on another waveguide channel. The multilayered waveguide taper structure array could potentially prevent this.It could also improve thin-film photovoltaic cells, which are a promising because they are less expensive and more flexible that traditional solar cells. The drawback, however, is that they don’t absorb as much light as traditional cells. Because the multilayered waveguide taper structure array can efficiently absorb the visible spectrum, as well as the infrared spectrum, it could potentially boost the amount of energy that thin-film solar cells generate.The multilayered waveguide taper array could help recycle waste heat generated by power plants and other industrial processes, as well as electronic devices such as televisions, smartphones and laptop computers.”It could be useful as an ultra compact thermal-absorption, collection and liberation device in the mid-infrared spectrum,” says Dengxin Ji, a PhD student in Gan’s lab and first author of the paper.It could even be used as a stealth, or cloaking, material for airplanes, ships and other vehicles to avoid radar, sonar, infrared and other forms of detection. …

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Daylight saving impacts timing of heart attacks

Still feeling the residual effects of springing ahead for daylight saving time? The hour of sleep lost — or gained — may play a bigger, perhaps more dangerous role in our body’s natural rhythm than we think. It seems moving the clock forward or backward may alter the timing of when heart attacks occur in the week following these time changes, according to research to be presented at the American College of Cardiology’s 63rd Annual Scientific Session.Data from the largest study of its kind in the U.S. reveal a 25 percent jump in the number of heart attacks occurring the Monday after we “spring forward” compared to other Mondays during the year — a trend that remained even after accounting for seasonal variations in these events. But the study showed the opposite effect is also true. Researchers found a 21 percent drop in the number of heart attacks on the Tuesday after returning to standard time in the fall when we gain an hour back.”What’s interesting is that the total number of heart attacks didn’t change the week after daylight saving time,” said Amneet Sandhu, M.D., cardiology fellow, University of Colorado in Denver, and lead investigator of the study. “But these events were much more frequent the Monday after the spring time change and then tapered off over the other days of the week. It may mean that people who are already vulnerable to heart disease may be at greater risk right after sudden time changes.”Heart attacks historically occur most often on Monday mornings. Sandhu explains that in looking at other “normal” Mondays, there is some variation in events, but it is not significant. However, when he and his team compared admissions from a database of non-federal Michigan hospitals the Monday before the start of daylight saving time and the Monday immediately after for four consecutive years, they found a consistent 34 percent increase in heart attacks from one week to the next (93 heart attacks the Monday before compared to 125 the week after the start of daylight saving time for the duration of the study.).Although researchers cannot say what might be driving the shift in heart attack timing after the start of daylight saving time, they have a theory.”Perhaps the reason we see more heart attacks on Monday mornings is a combination of factors, including the stress of starting a new work week and inherent changes in our sleep-wake cycle,” Sandhu said. …

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Revolutionary solar cells double as lasers

Latest research finds that the trailblazing ‘perovskite’ material used in solar cells can double up as a laser, strongly suggesting the astonishing efficiency levels already achieved in these cells is only part of the journey.Commercial silicon-based solar cells — such as those seen on the roofs of houses across the country — operate at about 20% efficiency for converting the Sun’s rays into electrical energy. It’s taken over 20 years to achieve that rate of efficiency.A relatively new type of solar cell based on a perovskite material — named for scientist Lev Perovski, who first discovered materials with this structure in the Ural Mountains in the 19th century — was recently pioneered by an Oxford research team led by Professor Henry Snaith.Perovskite solar cells, the source of huge excitement in the research community, already lie just a fraction behind commercial silicon, having reached a remarkable 17% efficiency after a mere two years of research — transforming prospects for cheap large-area solar energy generation.Now, researchers from Professor Sir Richard Friend’s group at Cambridge’s Cavendish Laboratory — working with Snaith’s Oxford group — have demonstrated that perovskite cells excel not just at absorbing light but also at emitting it. The new findings, recently published online in the Journal of Physical Chemistry Letters, show that these ‘wonder cells’ can also produce cheap lasers.By sandwiching a thin layer of the lead halide perovskite between two mirrors, the team produced an optically driven laser which proves these cells “show very efficient luminescence” — with up to 70% of absorbed light re-emitted.The researchers point to the fundamental relationship, first established by Shockley and Queisser in 1961, between the generation of electrical charges following light absorption and the process of ‘recombination’ of these charges to emit light.Essentially, if a material is good at converting light to electricity, then it will be good at converting electricity to light. The lasing properties in these materials raise expectations for even higher solar cell efficiencies, say the Oxbridge team, which — given that perovskite cells are about to overtake commercial cells in terms of efficiency after just two years of development — is a thrilling prospect.”This first demonstration of lasing in these cheap solution-processed semiconductors opens up a range of new applications,” said lead author Dr Felix Deschler of the Cavendish Laboratory. “Our findings demonstrate potential uses for this material in telecommunications and for light emitting devices.”Most commercial solar cell materials need expensive processing to achieve a very low level of impurities before they show good luminescence and performance. Surprisingly these new materials work well even when very simply prepared as thin films using cheap scalable solution processing.The researchers found that upon light absorption in the perovskite two charges (electron and hole) are formed very quickly — within 1 picosecond — but then take anywhere up to a few microseconds to recombine. This is long enough for chemical defects to have ceased the light emission in most other semiconductors, such as silicon or gallium arsenide. “These long carrier lifetimes together with exceptionally high luminescence are unprecedented in such simply prepared inorganic semiconductors,” said Dr Sam Stranks, co-author from the Oxford University team.”We were surprised to find such high luminescence efficiency in such easily prepared materials. This has great implications for improvements in solar cell efficiency,” said Michael Price, co-author from the group in Cambridge.Added Snaith: “This luminescent behaviour is an excellent test for solar cell performance — poorer luminescence (as in amorphous silicon solar cells) reduces both the quantum efficiency (current collected) and also the cell voltage.”Scientists say that this new paper sets expectations for yet higher solar cell performance from this class of perovskite semiconductors. Solar cells are being scaled up for commercial deployment by the Oxford spin-out, Oxford PV Ltd. …

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New way to filter light: May provide first directional selectivity for light waves

Light waves can be defined by three fundamental characteristics: their color (or wavelength), polarization, and direction. While it has long been possible to selectively filter light according to its color or polarization, selectivity based on the direction of propagation has remained elusive.But now, for the first time, MIT researchers have produced a system that allows light of any color to pass through only if it is coming from one specific angle; the technique reflects all light coming from other directions. This new approach could ultimately lead to advances in solar photovoltaics, detectors for telescopes and microscopes, and privacy filters for display screens.The work is described in a paper appearing this week in the journal Science, written by MIT graduate student Yichen Shen, professor of physics Marin Soljačić, and four others. “We are excited about this,” Soljačić says, “because it is a very fundamental building block in our ability to control light.”The new structure consists of a stack of ultrathin layers of two alternating materials where the thickness of each layer is precisely controlled. “When you have two materials, then generally at the interface between them you will have some reflections,” Soljačić explains. But at these interfaces, “there is this magical angle called the Brewster angle, and when you come in at exactly that angle and the appropriate polarization, there is no reflection at all.”While the amount of light reflected at each of these interfaces is small, by combining many layers with the same properties, most of the light can be reflected away — except for that coming in at precisely the right angle and polarization.Using a stack of about 80 alternating layers of precise thickness, Shen says, “We are able to reflect light at most of the angles, over a very broad band [of colors]: the entire visible range of frequencies.”Previous work had demonstrated ways of selectively reflecting light except for one precise angle, but those approaches were limited to a narrow range of colors of light. The new system’s breadth could open up many potential applications, the team says.Shen says, “This could have great applications in energy, and especially in solar thermophotovoltaics” — harnessing solar energy by using it to heat a material, which in turn radiates light of a particular color. That light emission can then be harnessed using a photovoltaic cell tuned to make maximum use of that color of light. But for this approach to work, it is essential to limit the heat and light lost to reflections, and re-emission, so the ability to selectively control those reflections could improve efficiency.The findings could also prove useful in optical systems, such as microscopes and telescopes, for viewing faint objects that are close to brighter objects — for example, a faint planet next to a bright star. By using a system that receives light only from a certain angle, such devices could have an improved ability to detect faint targets. …

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Gulf war illness not in veterans’ heads but in their mitochondria

Researchers at the UC San Diego School of Medicine have demonstrated for the first time that veterans of the 1990-91 Persian Gulf War who suffer from “Gulf War illness” have impaired function of mitochondria — the energy powerhouses of cells.The findings, published in the March 27, 2014 issue of PLOS ONE, could help lead to new treatments benefitting affected individuals — and to new ways of protecting servicepersons (and civilians) from similar problems in the future, said principal investigator Beatrice A. Golomb MD, PhD, professor of medicine.Golomb, with associate Hayley Koslik and Gavin Hamilton, PhD, a research scientist and magnetic resonance physicist, used the imaging technology to compare Gulf War veterans with diagnosed Gulf War illness to healthy controls. Cases were matched by age, sex and ethnicity.The technique used — 31-phosphorus magnetic resonance spectroscopy or 31P-MRS — reveals amounts of phosphorus-containing compounds in cells. Such compounds are important for cell energy production, in particular phosphocreatine or PCr, which declines in muscle cells during exercise. PCr recovery takes longer when mitochondrial function is impaired, and delayed recovery is recognized as a robust marker of mitochondrial dysfunction.Affected Gulf War veterans displayed significantly delayed PCr recovery after an exercise challenge. In fact, said Golomb, there was almost no overlap in the recovery times of Gulf War illness veterans compared to controls: All but one control participant had a recovery time-constant clustered under 31 seconds. In contrast, all but one Gulf Illness veteran had a recovery time-constant exceeding 35 seconds, with times ranging as high as 70 seconds.There were 14 participants in the study: seven Gulf War illness cases and seven matching controls. Golomb notes that the use of 1:1 matching markedly improves statistical “power,” allowing a smaller sample size. The separation between the two groups was “visibly striking, and the large average difference was statistically significant,” she said.Golomb noted that impaired mitochondrial function accounts for numerous features of Gulf War illness, including symptoms that have been viewed as perplexing or paradoxical.”The classic presentation for mitochondrial illness involves multiple symptoms spanning many domains, similar to what we see in Gulf War illness. These classically include fatigue, cognitive and other brain-related challenges, muscle problems and exercise intolerance, with neurological and gastrointestinal problems also common.”There are other similarities between patients with mitochondrial dysfunction and those suffering from Gulf War illness: Additional symptoms appear in smaller subsets of patients; varying patterns of symptoms and severity among individuals; different latency periods across symptoms, or times when symptoms first appear; routine blood tests that appear normal.”Some have sought to ascribe Gulf War illness to stress,” said Golomb, “but stress has proven not to be an independent predictor of the condition. …

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The search for seeds of black holes

How do you grow a supermassive black hole that is a million to a billion times the mass of our sun? Astronomers do not know the answer, but a new study using data from NASA’s Wide-field Infrared Survey Explorer, or WISE, has turned up what might be the cosmic seeds from which a black hole will sprout. The results are helping scientists piece together the evolution of supermassive black holes — powerful objects that dominate the hearts of all galaxies.Growing a black hole is not as easy as planting a seed in soil and adding water. The massive objects are dense collections of matter that are literally bottomless pits; anything that falls in will never come out. They come in a range of sizes. The smallest, only a few times greater in mass than our sun, form from exploding stars. The biggest of these dark beasts, billions of times the mass of our sun, grow together with their host galaxies over time, deep in the interiors. But how this process works is an ongoing mystery.Researchers using WISE addressed this question by looking for black holes in smaller, “dwarf” galaxies. These galaxies have not undergone much change, so they are more pristine than their heavier counterparts. In some ways, they resemble the types of galaxies that might have existed when the universe was young, and thus they offer a glimpse into the nurseries of supermassive black holes.In this new study, using data of the entire sky taken by WISE in infrared light, up to hundreds of dwarf galaxies have been discovered in which buried black holes may be lurking. …

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Canal between ears helps alligators pinpoint sound

By reptile standards, alligators are positively chatty. They are the most vocal of the non-avian reptiles and are known to be able to pinpoint the source of sounds with accuracy. But it wasn’t clear exactly how they did it because they lack external auditory structures.In a new study, an international team of biologists shows that the alligator’s ear is strongly directional because of large, air-filled channels connecting the two middle ears. This configuration is similar in birds, which have an interaural canal that increases directionality.”Mammals usually have large moveable ears, but alligators do not, so they have solved the problems of sound localization a little differently. This may also be the solution used by the alligator’s dinosaur relatives,” said Hilary Bierman, a biology lecturer at the University of Maryland.The study, which was led by Bierman and UMD Biology Professor Catherine Carr, was published online in the Journal of Experimental Biology on March 26, 2014. The research was funded by the National Institutes of Health, National Science Foundation, Danish National Science Foundation and Carlsberg Foundation.The UMD biologists — along with researchers from the University of Massachusetts Lowell, University of Colorado Medical School and University of Southern Denmark — collected anatomical, biophysical and electrophysiological measurements of alligators to investigate the mechanisms alligators use to locate sounds.”Different vertebrate lineages have evolved external and/or internal anatomical adaptations to enhance these auditory cues, such as pinnae and interaural canals,” said Bierman.First, the team tested how sound travelled around an alligator’s head to investigate whether the animal somehow channels sound, listening for tiny time and volume differences in the sound’s arrival at the two ears to help locate the origin. But the team found no evidence that the animal’s body alters sound transmission sufficiently for the animal to be able to detect the difference. And when the team measured alligators’ brainstem responses to sounds, they were too fast for the animals to sense these small time differences.Next, the team looked for internal structures in the alligators’ heads that might propagate sound between the two eardrums. Viewing slices through the heads of young alligators, the team could clearly see two channels linking the two middle ears that could transmit sound between the two eardrums.Sound reaches both sides of the eardrum — travelling externally to reach the outer side and through head structures to the internal side — to amplify the vibration at some frequencies when the head is aligned with the sound. This maximizes the pressure differences on the two sides of the eardrum, magnifying the time difference between the sound arriving at the ear drum via two different paths to allow the animal to pinpoint the source. …

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Bamboo-loving giant pandas also have a sweet tooth

Despite the popular conception of giant pandas as continually chomping on bamboo to fulfill a voracious appetite for this reedy grass, new research from the Monell Center reveals that this highly endangered species also has a sweet tooth. A combination of behavioral and molecular genetic studies demonstrated that the giant panda both possesses functional sweet taste receptors and also shows a strong preference for some natural sweeteners, including fructose and sucrose.”Examining an animal’s taste DNA can give us clues to their past diet, knowledge that is particularly important for endangered animals in captivity,” said study author Danielle Reed, PhD, a behavioral geneticist at Monell. “This process can provide information on approaches to keep such animals healthy.”The Monell researchers studied the giant pandas as part of a long-term project focused on understanding how taste preferences and diet selection are shaped by taste receptor genes.One previous study found that cats, which must eat meat in order to survive, had lost the ability to taste sweets due to a genetic defect that deactivates the sweet taste receptor.Although giant pandas and cats belong to the same taxonomic order, Carnivora, the giant pandas have a very different diet, as they feed almost exclusively on bamboo.Noting that bamboo is a grass-like plant that contains very small amounts of sugars and does not taste sweet to humans, the researchers wondered whether giant pandas, like their Carnivora cat relatives, had lost sweet taste perception. An alternate possibility was that the panda maintain a functional sweet taste receptor, similar to other plant-eating mammals.In this study, published online in the open-access journal PLOS ONE, eight giant pandas between three and 22 years of age were studied at the Shaanxi Wild Animal Rescue and Research Center in China over a six-month period.For taste preference tests, the animals were given two bowls of liquid and allowed to drink for five minutes. One bowl contained water and the other contained a solution of water mixed with one of six different natural sugars: fructose, galactose, glucose, lactose, maltose, and sucrose. Each sugar was presented at a low and a high concentration.The pandas preferred all the sugar solutions to plain water. This was especially evident for fructose and sucrose, as the animals avidly consumed a full liter of these sugary solutions within the respective five-minute test periods.”Pandas love sugar,” said Reed. “Our results can explain why Bao Bao, the six-month-old giant panda cub at the National Zoo in Washington, DC, is apparently relishing sweet potato as a first food during weaning.”Another series of preference tests explored the giant panda’s response to five artificial sweeteners. There was little to no preference for most artificial sweetener solutions, suggesting that giant pandas cannot taste or do not strongly perceive these compounds as being sweet.Parallel cell-based studies showed a relationship between the pandas’ behavior and how panda taste receptor cells respond to sweeteners in vitro. Using DNA collected from the giant pandas during routine health examinations, genes that code for the panda sweet taste receptor were isolated and then inserted into human host cells grown in culture. …

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Crows understand water displacement at the level of a small child: Show causal understanding of 5-7 year old child

New Caledonian crows may understand how to displace water to receive a reward, with the causal understanding level of a 5-7 year-old child, according to results published March 26, 2014, in the open access journal PLOS ONE by Sarah Jelbert from University of Auckland and colleagues.Understanding causal relationships between actions is a key feature of human cognition. However, the extent to which non-human animals are capable of understanding causal relationships is not well understood. Scientists used the Aesop’s fable riddle — in which subjects drop stones into water to raise the water level and obtain an out-of reach-reward — to assess New Caledonian crows’ causal understanding of water displacement. These crows are known for their intelligence and innovation, as they are the only non-primate species able to make tools, such as prodding sticks and hooks. Six wild crows were tested after a brief training period for six experiments, during which the authors noted rapid learning (although not all the crows completed every experiment). The authors note that these tasks did not test insightful problem solving, but were directed at the birds’ understanding of volume displacement.Crows completed 4 of 6 water displacement tasks, including preferentially dropping stones into a water-filled tube instead of a sand-filled tube, dropping sinking objects rather than floating objects, using solid objects rather than hollow objects, and dropping objects into a tube with a high water level rather than a low one. However, they failed two more challenging tasks, one that required understanding of the width of the tube, and one that required understanding of counterintuitive cues for a U-shaped displacement task. According to the authors, results indicate crows may possess a sophisticated — but incomplete — understanding of the causal properties of volume displacement, rivalling that of 5-7 year old children.Sarah Jelbert added, “These results are striking as they highlight both the strengths and limits of the crows’ understanding. In particular, the crows all failed a task which violated normal causal rules, but they could pass the other tasks, which suggests they were using some level of causal understanding when they were successful.”Story Source:The above story is based on materials provided by PLOS. Note: Materials may be edited for content and length.

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Salamanders shrinking as their mountain havens heat up

Wild salamanders living in some of North America’s best salamander habitat are getting smaller as their surroundings get warmer and drier, forcing them to burn more energy in a changing climate.That’s the key finding of a new study, published March 25 in the journal Global Change Biology, that examined museum specimens caught in the Appalachian Mountains from 1957 to 2007 and wild salamanders measured at the same sites in 2011-2012. The salamanders studied from 1980 onward were, on average, 8% smaller than their counterparts from earlier decades. The changes were most marked in the Southern Appalachians and at low elevations — settings where detailed weather records showed the climate has warmed and dried out most.Scientists have predicted that some animals will get smaller in response to climate change, and this is strongest confirmation of that prediction.”This is one of the largest and fastest rates of change ever recorded in any animal,” said Karen R. Lips, an associate professor of biology at the University of Maryland and the study’s senior author. “We don’t know exactly how or why it’s happening, but our data show it is clearly correlated with climate change.” And it’s happening at a time when salamanders and other amphibians are in distress, with some species going extinct and others dwindling in number.”We don’t know if this is a genetic change or a sign that the animals are flexible enough to adjust to new conditions,” Lips said. “If these animals are adjusting, it gives us hope that some species are going to be able to keep up with climate change.”The study was prompted by the work of University of Maryland Prof. Emeritus Richard Highton, who began collecting salamanders in the Appalachian Mountains in 1957. The geologically ancient mountain range’s moist forests and long evolutionary history make it a global hot spot for a variety of salamander species. Highton collected hundreds of thousands of salamanders, now preserved in jars at the Smithsonian Institution’s Museum Service Center in Suitland, MD.But Highton’s records show a mysterious decline in the region’s salamander populations beginning in the 1980s. Lips, an amphibian expert, saw a similar decline in the frogs she studied in Central America, and tracked it to a lethal fungal disease. …

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Million suns shed light on fossilized plant

Scientists have used one of the brightest lights in the Universe to expose the biochemical structure of a 50 million-year-old fossil plant to stunning visual effect.The team of palaeontologists, geochemists and physicists investigated the chemistry of exceptionally preserved fossil leaves from the Eocene-aged ‘Green River Formation’ of the western United States by bombarding the fossils with X-rays brighter than a million suns produced by synchrotron particle accelerators.Researchers from Britain’s University of Manchester and Diamond Light Source and the Stanford Synchrotron Radiation Lightsource in the US have published their findings, along with amazing images, in Metallomics; one of the images is featured on the cover of the latest edition of the Royal Society of Chemistry journal.Lead author Dr Nicholas Edwards, a postdoctoral researcher at The University of Manchester, said: “The synchrotron has already shown its potential in teasing new information from fossils, in particular our group’s previous work on pigmentation in fossil animals. With this study, we wanted to use the same techniques to see whether we could extract a similar level of biochemical information from a completely different part of the tree of life.”To do this we needed to test the chemistry of the fossil plants to see if the fossil material was derived directly from the living organisms or degraded and replaced by the fossilisation process.”We know that plant chemistry can be preserved over hundreds of millions of years — this preserved chemistry powers our society today in the form of fossil fuels. However, this is just the ‘combustible’ part; until now no one has completed this type of study of the other biochemical components of fossil plants, such as metals.”By combining the unique capabilities of two synchrotron facilities, the team were able to produce detailed images of where the various elements of the periodic table were located within both living and fossil leaves, as well as being able to show how these elements were combined with other elements.The work shows that the distribution of copper, zinc and nickel in the fossil leaves was almost identical to that in modern leaves. Each element was concentrated in distinct biological structures, such as the veins and the edges of the leaves, and the way these trace elements and sulphur were attached to other elements was very similar to that seen in modern leaves and plant matter in soils.Co-author Professor Roy Wogelius, from Manchester’s School of Earth, Atmospheric and Environmental Sciences, said: “This type of chemical mapping and the ability to determine the atomic arrangement of biologically important elements, such as copper and sulphur, can only be accomplished by using a synchrotron particle accelerator.”In one beautiful specimen, the leaf has been partially eaten by prehistoric caterpillars — just as modern caterpillars feed — and their feeding tubes are preserved on the leaf. The chemistry of these fossil tubes remarkably still matches that of the leaf on which the caterpillars fed.”The data from a suite of other techniques has led the team to conclude that the chemistry of the fossil leaves is not wholly sourced from the surrounding environment, as has previously been suggested, but represents that of the living leaves. Another modern-day connection suggests a way in which these specimens are so beautifully preserved over millions of years.Manchester palaeontologist and co-author Dr Phil Manning said: “We think that copper may have aided preservation by acting as a ‘natural’ biocide, slowing down the usual microbial breakdown that would destroy delicate leaf tissues. This property of copper is used today in the same wood preservatives that you paint on your garden fence before winter approaches.”Story Source:The above story is based on materials provided by Manchester University. Note: Materials may be edited for content and length.

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Male Eurasian jays know that their female partners’ desires can differ from their own

New research shows that male Eurasian Jays in committed relationships are able to share food with their female partner according to her current desire.The behaviour suggests the potential for ‘state-attribution’ in these birds — the ability to recognise and understand the internal life and psychological states of others.The research was carried out in Professor Nicola Clayton’s Comparative Cognition lab at Cambridge University’s Department of Psychology, and is published today in the journal PNAS.Researchers tested mated jays and separated males from females. The females were fed one particular larvae, either wax moth or mealworm — a treat for the birds, like chocolates — allowing the males to observe from an adjacent compartment through a transparent window.Once the pairs were reintroduced and the option of both larvae was presented, the males would choose to feed their partner the other type of larvae, to which she hadn’t previously had access — a change in diet welcomed by the female.Through different tests using variations on food and visual access to the females during feeding, the researchers show that the males needed to actually see the females eating enough of and become sated by one type of larvae — called ‘specific satiety’ — to know to offer them the other type once reunited.This demonstrates that the males’ sharing pattern was not a response to their partner’s behaviour indicating her preference but a response to the change in her internal state.”Our results raise the possibility that these birds may be capable of ascribing desire to their mates — acknowledging an ‘internal life’ in others like that of their own,” said Ljerka Ostojic, who led the research.”Ascribing internal states to other individuals requires the basic understanding that others are distinct from the self and others’ internal states are independent from, and differ from, one’s own.When there was no opportunity to feed the female, males chose between the two foods according to their own desires. Only when they could share with the female did they disengage from their own desires and select food the female wanted.The researchers believe that this ability to respond to another’s internal state in a cooperative situation might be important for species living in long-term relationships. Food-sharing is an important courtship behaviour for the Jays — so the ability to determine which food is currently desired by his partner might increase the male’s value as a mate.”A comparison might be a man giving his wife chocolates. The giving and receiving of chocolates is an important ‘pair-bonding’ ritual — but, a man that makes sure he gives his wife the chocolates she currently really wants will improve his bond with her much more effectively — getting in the good books, and proving himself a better life partner.”Story Source:The above story is based on materials provided by University of Cambridge. The original story is licensed under a Creative Commons Licence. Note: Materials may be edited for content and length.

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Biologists use sound to identify breeding grounds of endangered whales

Remote acoustic monitoring among endangered whales is the subject of a major article by two doctoral students in The College of Arts and Sciences.Leanna Matthews and Jessica McCordic, members of the Parks Lab in the Department of Biology, have co-authored “Remote Acoustic Monitoring of North Atlantic Right Whales Reveals Seasonal and Diel Variations in Acoustic Behavior.” The article appears in the current issue of PLOS ONE, an inclusive, peer-reviewed, open-access resource from the Public Library of Science in San Francisco.Susan Parks, assistant professor of biology for whom the lab is named, says the article confirms what many conservationists fear — that Roseway Basin, a heavily traveled shipping lane, off the coast of Nova Scotia, is a vital habitat area for the endangered North Atlantic right whale.”Remote acoustic monitoring is an important tool for understanding patterns in animal communication, and studies on the seasonality of context-specific acoustic signals allow inferences to be made about the behavior and habitat use of certain species,” says Parks, an expert in behavioral ecology, acoustic communication and marine science. “Our results support the hypothesis that the North Atlantic right whale’s breeding season occurs mostly from August to November and that this basin is a widely used habitat area.”More than 30 percent of all right whales use Roseway Basin, part of a larger geological formation called the Scotian Shelf, throughout the year. With only 400-500 in existence, these whales, says Parks, must congregate in the basin to feed and find mates.Already, the U.S. and Canadian governments have taken steps to redirect shipping traffic, in response to several fatal collisions with right whales.Matthews, whose research includes animal behavior and physiology, says the object of the article is to determine how and when Roseway Basin is used for male breeding activities.”Part of the answer lies in a loud ‘gunshot’ sound, made by the male whale,” says Matthews, the article’s lead author. “We’re not exactly sure what the gunshot is, but we think it may be a male-to-male antagonistic signal or an advertisement to females. … During a two-year period, we used non-invasive acoustic monitoring to analyze gunshots at two locations on the Scotian Shelf. The resultant data has provided tremendous insights into the whales’ feeding and mating habits.”Matthews and her team found that gunshot sound production occurred mainly in the autumn and, more often than not, at night. Researchers say this kind of information is essential to not only the individual fitness of each whale, but also the survival of the species, in general.McCordic, whose research spans animal behavior and communication, says the observed seasonal increase in gunshot sound production is consistent with the current understanding of the right whale breeding season.”Our results demonstrate that detection of gunshots with remote acoustic monitoring can be a reliable way to track shifts in distribution and changes in acoustic behavior, including possible mating activities,” she says, acknowledging David Mellinger, associate professor of marine bioacoustics at Oregon State University, who collected and provided access to the recordings used in the study. “It also provides a better understanding of right whale behavior and what needs to be done with future conservation efforts.”Parks, who assisted with the article, is proud of her students’ accomplishments.”Right whales are increasingly rare, and Leanna’s and Jessica’s research helps us understand how to better protect them,” she says. “By identifying potential breeding areas, we might be able to save this critically endangered species.”Story Source:The above story is based on materials provided by Syracuse University. …

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Exploding stars prove Newton’s law of gravity unchanged over cosmic time

Australian astronomers have combined all observations of supernovae ever made to determine that the strength of gravity has remained unchanged over the last nine billion years.Newton’s gravitational constant, known as G, describes the attractive force between two objects, together with the separation between them and their masses. It has been previously suggested that G could have been slowly changing over the 13.8 billion years since the Big Bang.If G has been decreasing over time, for example, this would mean that Earth’s distance to the Sun was slightly larger in the past, meaning that we would experience longer seasons now compared to much earlier points in Earth’s history.But researchers at Swinburne University of Technology in Melbourne have now analysed the light given off by 580 supernova explosions in the nearby and far Universe and have shown that the strength of gravity has not changed.”Looking back in cosmic time to find out how the laws of physics may have changed is not new” Swinburne Professor Jeremy Mould said. “But supernova cosmology now allows us to do this with gravity.”A Type 1a supernova marks the violent death of a star called a white dwarf, which is as massive as our Sun but packed into a ball the size of our Earth.Our telescopes can detect the light from this explosion and use its brightness as a ‘standard candle’ to measure distances in the Universe, a tool that helped Australian astronomer Professor Brian Schmidt in his 2011 Nobel Prize winning work, discovering the mysterious force Dark Energy.Professor Mould and his PhD student Syed Uddin at the Swinburne Centre for Astrophysics and Supercomputing and the ARC Centre of Excellence for All-sky Astrophysics (CAASTRO) assumed that these supernova explosions happen when a white dwarf reaches a critical mass or after colliding with other stars to ‘tip it over the edge’.”This critical mass depends on Newton’s gravitational constant G and allows us to monitor it over billions of years of cosmic time — instead of only decades, as was the case in previous studies,” Professor Mould said.Despite these vastly different time spans, their results agree with findings from the Lunar Laser Ranging Experiment that has been measuring the distance between Earth and the Moon since NASA’s Apollo missions in the 1960s and has been able to monitor possible variations in G at very high precision.”Our cosmological analysis complements experimental efforts to describe and constrain the laws of physics in a new way and over cosmic time.” Mr Uddin said.In their current publication, the Swinburne researchers were able to set an upper limit on the change in Newton’s gravitational constant of 1 part in 10 billion per year over the past nine billion years.The ARC Centre of Excellence for All-sky Astrophysics (CAASTRO) is a collaboration between The Australian National University, The University of Sydney, The University of Melbourne, Swinburne University of Technology, the University of Queensland, The University of Western Australia and Curtin University, the latter two participating together as the International Centre for Radio Astronomy Research. CAASTRO is funded under the Australian Research Council Centre of Excellence program, with additional funding from the seven participating universities and from the NSW State Government’s Science Leveraging Fund.The research is published this month in the Publications of the Astronomical Society of Australia.Story Source:The above story is based on materials provided by Swinburne University of Technology. Note: Materials may be edited for content and length.

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DNA from fossils reveal origin of Norwegian lemmings

A new ancient DNA study shows that the Norwegian lemming has a unique history. In contrast to other mammals in Fennoscandia, the Norwegian lemming may have survived the last Ice Age in the far north, sealed off from the rest of the world by gigantic ice sheets. This conclusion is drawn by an international team of researchers in an article published this week in the journal Molecular Ecology.The Norwegian lemming is an iconic small mammal that is unique to the Fennoscandian mountain tundra. Known for its dramatic fluctuations in population size, it is a keystone species in the mountain tundra ecosystem. But its origin has until now remained somewhat of a mystery.Twenty thousand years ago, Fennoscandia was covered by a thick ice sheet. Animals and plants in the region are therefore thought to originate from populations that lived to the south or east of the ice sheet, and colonised Fennoscandia as the ice melted. With this in mind, and international team of scientists, led by researchers at the Swedish Museum of Natural History, set out to investigate from where the Norwegian lemming originated at the end of the last Ice Age. To do this, the researchers retrieved and analysed ancient DNA from lemming populations that surrounded the ice sheet during the last Ice Age.- “We found that even though the populations surrounding the ice sheet were closely related to modern day lemmings, none of them were similar enough to be the direct ancestor of the Norwegian lemming,” says Love Daln, Associate Professor at the Swedish Museum of Natural History.After eliminating these populations as potential sources, the researchers concluded that the only remaining explanation was that the Norwegian lemming originates from a population that survived the last glaciation somewhere locally in Fennoscandia. The exact location where the Norwegian lemming could have survived the last glaciation is not clear, but likely places include coastal areas or mountain plateaus sticking out from the ice sheet.”The Norwegian lemming is the only endemic mammal in Fennoscandia, and its unusual origin is probably the reason why,” says Vendela Lagerholm, lead author on the study.Story Source:The above story is based on materials provided by Expertsvar. Note: Materials may be edited for content and length.

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