Ammonia pollution from agricultural sources poses larger health costs than previously estimated, according to NASA-funded research.Harvard University researchers Fabien Paulot and Daniel Jacob used computer models including a NASA model of chemical reactions in the atmosphere to better represent how ammonia interacts in the atmosphere to form harmful particulate matter. The improved simulation helped the scientists narrow in on the estimated health costs from air pollution associated with food produced for export — a growing sector of agriculture and a source of trade surplus.”The ‘cost’ is an economic concept to measure how much people are willing to pay to avoid a risk,” Paulot said. “This is used to quantify the cost for society but also to evaluate the benefits of mitigation.”The new research by Paulot and Jacob calculate the health cost associated with the ammonia emissions from agriculture exports to be $36 billion a year — equal to about half of the revenue generated by those same exports — or $100 per kilogram of ammonia. The study was published December 2013 in Environmental Science & Technology.The new estimate is about double the current estimate by the U.S. Environmental Protection Agency, which suggests a cost of $47 per kilogram of ammonia. The scientists say the new estimate is on the high end of the spectrum, which reflects the need for more research into characterizing the relationship between agricultural ammonia emissions and the formation of the harmful fine particulate matter — a relationship that’s not as straightforward as previous estimates assumed.”The effect of ammonia on fine particulate is complex, and we believe that the models previously used in the United States to price ammonia emissions have not captured this well,” Paulot said.Manure from livestock and fertilizer for crops release ammonia to the atmosphere. In the air, ammonia mixes with other emissions to form microscopic airborne particles, or particulates. The particulates that pose the greatest health risk are those that measure no more than 2.5 micrometers across, or about 1/30 the width of a human hair, which when inhaled can become lodged deep within the lungs. Long-term exposure has been linked to heart and lung diseases and even death. As such, the particles are on the list of six common air pollutants regulated by EPA’s National Ambient Air Quality Standards.An increase in ammonia, however, does not translate to an equal increase in particulates. …Read more
Earth’s magnetic field, or magnetosphere, stretches from the planet’s core out into space, where it meets the solar wind, a stream of charged particles emitted by the sun. For the most part, the magnetosphere acts as a shield to protect Earth from this high-energy solar activity.But when this field comes into contact with the sun’s magnetic field — a process called “magnetic reconnection” — powerful electrical currents from the sun can stream into Earth’s atmosphere, whipping up geomagnetic storms and space weather phenomena that can affect high-altitude aircraft, as well as astronauts on the International Space Station.Now scientists at MIT and NASA have identified a process in Earth’s magnetosphere that reinforces its shielding effect, keeping incoming solar energy at bay.By combining observations from the ground and in space, the team observed a plume of low-energy plasma particles that essentially hitches a ride along magnetic field lines — streaming from Earth’s lower atmosphere up to the point, tens of thousands of kilometers above the surface, where the planet’s magnetic field connects with that of the sun. In this region, which the scientists call the “merging point,” the presence of cold, dense plasma slows magnetic reconnection, blunting the sun’s effects on Earth.”The Earth’s magnetic field protects life on the surface from the full impact of these solar outbursts,” says John Foster, associate director of MIT’s Haystack Observatory. “Reconnection strips away some of our magnetic shield and lets energy leak in, giving us large, violent storms. These plasmas get pulled into space and slow down the reconnection process, so the impact of the sun on the Earth is less violent.”Foster and his colleagues publish their results in this week’s issue of Science. The team includes Philip Erickson, principal research scientist at Haystack Observatory, as well as Brian Walsh and David Sibeck at NASA’s Goddard Space Flight Center.Mapping Earth’s magnetic shieldFor more than a decade, scientists at Haystack Observatory have studied plasma plume phenomena using a ground-based technique called GPS-TEC, in which scientists analyze radio signals transmitted from GPS satellites to more than 1,000 receivers on the ground. Large space-weather events, such as geomagnetic storms, can alter the incoming radio waves — a distortion that scientists can use to determine the concentration of plasma particles in the upper atmosphere. Using this data, they can produce two-dimensional global maps of atmospheric phenomena, such as plasma plumes.These ground-based observations have helped shed light on key characteristics of these plumes, such as how often they occur, and what makes some plumes stronger than others. But as Foster notes, this two-dimensional mapping technique gives an estimate only of what space weather might look like in the low-altitude regions of the magnetosphere. To get a more precise, three-dimensional picture of the entire magnetosphere would require observations directly from space.Toward this end, Foster approached Walsh with data showing a plasma plume emanating from Earth’s surface, and extending up into the lower layers of the magnetosphere, during a moderate solar storm in January 2013. …Read more
The key characteristics of birds which allow them to fly — their wings and their small size — arose much earlier than previously thought, according to new research from the Universities of Bristol and Sheffield into the Paraves, the first birds and their closest dinosaurian relatives which lived 160 to 120 million years ago.Mark Puttick and colleagues investigated the rates of evolution of the two key characteristics that preceded flight: body size and forelimb length. In order to fly, hulking meat-eating dinosaurs had to shrink in size and grow much longer arms to support their feathered wings.”We were really surprised to discover that the key size shifts happened at the same time, at the origin of Paraves,” said Mr Puttick of Bristol’s School of Earth Sciences. “This was at least 20 million years before the first bird, the famous Archaeopteryx, and it shows that flight in birds arose through several evolutionary steps.”Being small and light is important for a flyer, and it now seems a whole group of dozens of little dinosaurs were lightweight and had wings of one sort or another. Most were gliders or parachutists, spreading their feathered wings, but not flapping them.”Out of all these flappers and gliders, only the birds seem to have been capable of powered flight,” said co-author Mike Benton, Professor of Vertebrate Palaeontology at Bristol.”But you wouldn’t have picked out Archaeopteryx as the founder of a remarkable new group.”The study applied new numerical methods that calculate the rate of evolution of different characteristics across a whole evolutionary tree, and identify where bursts of fast evolution occurred.”Up to now you could only have guessed roughly where the major evolutionary transitions occurred,” said Dr Gavin Thomas of the University of Sheffield, “but the new methods pinpoint the size changes. The small size of birds and their long wings originated long before birds themselves did.”Birds owe their success to their flight, wings and feathers. Until the 1990s, when the first feathered dinosaurs were found in China, birds were thought to have originated rapidly, marking a major transition from dinosaurs. Now, we know that Archaeopteryx was only one of a large number of small, flying dinosaurs.”The origin of birds used to be seen as a rapid transition,” said Mark Puttick, “but now we know that the key characteristics we associate with them arose much earlier.”Story Source:The above story is based on materials provided by University of Bristol. Note: Materials may be edited for content and length.Read more
Researchers recently discovered that a common space weather phenomenon on the outskirts of Earth’s magnetic bubble, the magnetosphere, has much larger repercussions for Venus. The giant explosions, called hot flow anomalies, can be so large at Venus that they’re bigger than the entire planet and they can happen multiple times a day.”Not only are they gigantic,” said Glyn Collinson, a space scientist at NASA’s Goddard Space Flight Center in Greenbelt, Md. “But as Venus doesn’t have a magnetic field to protect itself, the hot flow anomalies happen right on top of the planet. They could swallow the planet whole.”Collinson is the first author of a paper on these results that appeared online in the Journal of Geophysical Research in February 2014. The work is based on observations from the European Space Agency’s Venus Express. The results show just how large and how frequent this kind of space weather is at Venus.Earth is protected from the constant streaming solar wind of radiation by its magnetosphere. Venus, however, has no such luck. A barren, inhospitable planet, with an atmosphere so dense that spacecraft landing there are crushed within hours, Venus has no magnetic protection.Scientists like to compare the two: What happened differently at Earth to make it into the life-supporting planet it is today? What would Earth be like without its magnetic field?At Earth, hot flow anomalies do not make it inside the magnetosphere, but they release so much energy just outside that the solar wind is deflected, and can be forced to move back toward the sun. Without a magnetosphere, what happens at Venus is very different.Venus’s only protection from the solar wind is the charged outer layer of its atmosphere called the ionosphere. …Read more
By exploring how creatures in nature are able to fly by flapping their wings, Virginia Tech researchers hope to apply that knowledge toward designing small flying vehicles known as “micro air vehicles” with flapping wings.More than 1,000 species of bats have hand membrane wings, meaning that their fingers are essentially “webbed” and connected by a flexible membrane. But understanding how bats use their wings to manipulate the air around them is extremely challenging — primarily because both experimental measurements on live creatures and the related computer analysis are quite complex.In Virginia Tech’s study of fruit bat wings, the researchers used experimental measurements of the movements of the bats’ wings in real flight, and then used analysis software to see the direct relationship between wing motion and airflow around the bat wing. They report their findings in the journal Physics of Fluids.”Bats have different wing shapes and sizes, depending on their evolutionary function. Typically, bats are very agile and can change their flight path very quickly — showing high maneuverability for midflight prey capture, so it’s of interest to know how they do this,” explained Danesh Tafti, the William S. Cross professor in the Department of Mechanical Engineering and director of the High Performance Computational Fluid Thermal Science and Engineering Lab at Virginia Tech.To give you an idea of the size of a fruit bat, it weighs roughly 30 grams and a single fully extended wing is about 17 x 9 cm in length, according to Tafti.Among the biggest surprises in store for the researchers was how bat wings manipulated the wing motion with correct timing to maximize the forces generated by the wing. “It distorts its wing shape and size continuously during flapping,” Tafti noted.For example, it increases the area of the wing by about 30 percent to maximize favorable forces during the downward movement of the wing, and it decreases the area by a similar amount on the way up to minimize unfavorable forces. The force coefficients generated by the wing are “about two to three times greater than a static airfoil wing used for large airplanes,” said Kamal Viswanath, a co-author who was a graduate research assistant working with Tafti when the work was performed and is now a research engineer at the U.S. Naval Research Lab’s Laboratories for Computational Physics and Fluid Dynamics.This study was just an initial step in the researchers’ work. “Next, we’d like to explore deconstructing the seemingly complex motion of the bat wing into simpler motions, which is necessary to make a bat-inspired flying robot,” said Viswanath. The researchers also want to keep the wing motion as simple as possible, but with the same force production as that of a real bat.”We’d also like to explore other bat wing motions, such as a bat in level flight or a bat trying to maneuver quickly to answer questions, including: What are the differences in wing motion and how do they translate to air movement and forces that the bat generates? …Read more
New research that revises the rules allowing scientists to decipher color in dinosaurs may also provide a tool for understanding the evolutionary emergence of flight and changes in dinosaur physiology prior to its origin.In a survey comparing the hair, skin, fuzz and feathers of living terrestrial vertebrates and fossil specimens, a research team from The University of Texas at Austin, the University of Akron, the China University of Geosciences and four other Chinese institutions found evidence for evolutionary shifts in the rules that govern the relationship between color and the shape of pigment-containing organelles known as melanosomes, as reported in the Feb. 13 edition of Nature.At the same time, the team unexpectedly discovered that ancient maniraptoran dinosaurs, paravians, and living mammals and birds uniquely shared the evolutionary development of diverse melanosome shapes and sizes. (Diversity in the shape and size of melanosomes allows scientists to decipher color.) The evolution of diverse melanosomes in these organisms raises the possibility that melanosome shape and size could yield insights into dinosaur physiology.Melanosomes have been at the center of recent research that has led scientists to suggest the colors of ancient fossil specimens covered in fuzz or feathers.Melanosomes contain melanin, the most common light-absorbing pigment found in animals. Examining the shape of melanosomes from fossil specimens, scientists have recently suggested the color of several ancient species, including the fuzzy first-discovered feathered dinosaur Sinosauropteryx, and feathered species like Microraptor and Anchiornis.According to the new research, color-decoding works well for some species, but the color of others may be trickier than thought to reconstruct.Comparing melanosomes of 181 extant specimens, 13 fossil specimens and all previously published data on melanosome diversity, the researchers found that living turtles, lizards and crocodiles, which are ectothermic (commonly known as cold-blooded), show much less diversity in the shape of melanosomes than birds and mammals, which are endothermic (warm-blooded, with higher metabolic rates).The limited diversity in melanosome shape among living ectotherms shows little correlation to color. The same holds true for fossil archosaur specimens with fuzzy coverings scientists have described as “protofeathers” or “pycnofibers.” In these specimens, melanosome shape is restricted to spherical forms like those in modern reptiles, throwing doubt on the ability to decipher the color of these specimens from fossil melanosomes.In contrast, in the dinosaur lineage leading to birds, the researchers found an explosion in the diversity of melanosome shape and size that appears to correlate to an explosion of color within these groups. The shift in diversity took place abruptly, near the origin of pinnate feathers in maniraptoran dinosaurs.”This points to a profound change at a pretty discrete point,” says author Julia Clarke of The University of Texas at Austin’s Jackson School of Geosciences. “We’re seeing an explosion of melanosome diversity right before the origin of flight associated with the origin of feathers.”What surprised the researchers was a similarity in the pattern of melanosome diversity among ancient maniraptoran dinosaurs, paravians, and living mammals and birds.”Only in living, warm-blooded vertebrates that independently evolved higher metabolic rates do we see the melanosome diversity we also see in feathered dinosaurs,” said co-author Matthew Shawkey of The University of Akron.Many of the genes involved in the melanin color system are also involved in other core processes such as food intake, the stress axis, and reproductive behaviors. Because of this, note the researchers, it is possible that the evolution of diverse melanosome shapes is linked to larger changes in energetics and physiology.Melanosome shape could end up offering a new tool for studying endothermy in fossil specimens, a notoriously challenging subject for paleontologists.Because the explosion of diversity in melanosomes appears to have taken place right at the origin of pinnate feathers, the change may indicate that a key shift in dinosaurian physiology occurred prior to the origin of flight.”We are far from understanding the exact nature of the shift that may have occurred,” says Clarke. “But if changes in genes involved in both coloration and other aspects of physiology explain the pattern we see, these precede flight and arise close to the origin of feathers.”It is possible, notes Clarke, that a diversity in melanosome shape (and correlated color changes) resulted from an increased evolutionary role for signaling and sexual selection that had a carryover effect on physiology, or that a change in physiology closely preceded changes in color patterning. At this point, she stresses, both ideas are speculative.”What is interesting is that trying to get at color in extinct animals may have just started to give us some insights into changes in the physiology of dinosaurs.”Read more
For the past eight years, scientists have been working to make sense of why some satellite data seemed to show the Amazon rain forest “greening-up” during the region’s dry season each year from June to October. The green-up indicated productive, thriving vegetation in spite of limited rainfall.Now, a new NASA study published today in the journal Nature shows that the appearance of canopy greening is not caused by a biophysical change in Amazon forests, but instead by a combination of shadowing within the canopy and the way that satellite sensors observe the Amazon during the dry season.Correcting for this artifact in the data, Doug Morton, of NASA’s Goddard Space Flight Center in Greenbelt, Md., and colleagues show that Amazon forests, at least on the large scale, maintain a fairly constant greenness and canopy structure throughout the dry season. The findings have implications for how scientists seek to understand seasonal and interannual changes in Amazon forests and other ecosystems.”Scientists who use satellite observations to study changes in Earth’s vegetation need to account for seasonal differences in the angles of solar illumination and satellite observation,” Morton said.Isolating the apparent green-up mechanismThe MODIS, or Moderate Resolution Imaging Spectroradiometer, sensors that fly aboard NASA’s Terra and Aqua satellites make daily observations over the huge expanse of Amazon forests. An area is likely covered in green vegetation if sensors detect a relatively small amount of red light — absorbed in abundance by plants for photosynthesis — but see a large amount of near-infrared light, which plants primarily reflect. Scientists use the ratio of red and near-infrared light as a measure of vegetation “greenness.”Numerous hypotheses have been put forward to explain why Amazon forests appear greener in MODIS data as the dry season progresses. Perhaps young leaves, known to reflect more near-infrared light, replace old leaves? Or, possibly trees add more leaves to capture sunlight in the dry season when the skies are less cloudy.Unsettled by the lack of definitive evidence explaining the magnitude of the green-up, Morton and colleagues set out to better characterize the phenomenon. They culled satellite observations from MODIS and NASA’s Ice Cloud and land Elevation Satellite (ICESat) Geosciences Laser Altimeter System (GLAS), which can provide an independent check on the seasonal differences in Amazon forest structure.The team next used a theoretical model to demonstrate how changes in forest structure or reflectance properties have distinct fingerprints in MODIS and GLAS data. Only one of the hypothesized mechanisms for the green-up, changes in sun-sensor geometry, was consistent with the satellite observations.”We think we have uncovered the mechanism for the appearance of seasonal greening of Amazon forests — shadowing within the canopy that changes the amount of near-infrared light observed by MODIS,” Morton said.Seeing the Amazon in a new lightIn June, when the sun is as low and far north as it will get, shadows are abundant. By September, around the time of the equinox, Amazon forests at the equator are illuminated from directly overhead. …Read more
Oct. 16, 2013 — Earth’s most eminent emissary to Mars has just proven that those rare Martian visitors that sometimes drop in on Earth — a.k.a. Martian meteorites — really are from the Red Planet. A key new measurement of Mars’ atmosphere by NASA’s Curiosity rover provides the most definitive evidence yet of the origins of Mars meteorites while at the same time providing a way to rule out Martian origins of other meteorites.The new measurement is a high-precision count of two forms of argon gas — Argon-36 and Argon-38-accomplished by the Sample Analysis at Mars (SAM) instrument on Curiosity. These lighter and heavier forms, or isotopes, of argon exist naturally throughout the solar system. But on Mars the ratio of light to heavy argon is skewed because a lot of that planet’s original atmosphere was lost to space, with the lighter form of argon being taken away more readily because it rises to the top of the atmosphere more easily and requires less energy to escape. That’s left the Martian atmosphere relatively enriched in the heavier Argon-38.Years of past analyses by Earth-bound scientists of gas bubbles trapped inside Martian meteorites had already narrowed the Martian argon ratio to between 3.6 and 4.5 (that is 3.6 to 4.5 atoms of Argon-36 to every one Argon-38) with the supposed Martian “atmospheric” value near four. Measurements by NASA’s Viking landers in the 1970’s put the Martian atmospheric ratio in the range of four to seven. The new SAM direct measurement on Mars now pins down the correct argon ratio at 4.2.”We really nailed it,” said Sushil Atreya of the University of Michigan, Ann Arbor, the lead author of a paper reporting the finding today in Geophysical Research Letters, a journal of the American Geophysical Union. “This direct reading from Mars settles the case with all Martian meteorites,” he said.One of the reasons scientists have been so interested in the argon ratio in Martian meteorites is that it was — before Curiosity — the best measure of how much atmosphere Mars has lost since the planet’s earlier, wetter, warmer days billions of years ago. …Read more
Aug. 29, 2013 — Data from a NASA airborne science mission reveals evidence of a large and previously unknown canyon hidden under a mile of Greenland ice.The canyon has the characteristics of a winding river channel and is at least 460 miles (750 kilometers) long, making it longer than the Grand Canyon. In some places, it is as deep as 2,600 feet (800 meters), on scale with segments of the Grand Canyon. This immense feature is thought to predate the ice sheet that has covered Greenland for the last few million years.”One might assume that the landscape of the Earth has been fully explored and mapped,” said Jonathan Bamber, professor of physical geography at the University of Bristol in the United Kingdom, and lead author of the study. “Our research shows there’s still a lot left to discover.”Bamber’s team published its findings Thursday in the journal Science.The scientists used thousands of miles of airborne radar data, collected by NASA and researchers from the United Kingdom and Germany over several decades, to piece together the landscape lying beneath the Greenland ice sheet.A large portion of this data was collected from 2009 through 2012 by NASA’s Operation IceBridge, an airborne science campaign that studies polar ice. One of IceBridge’s scientific instruments, the Multichannel Coherent Radar Depth Sounder, can see through vast layers of ice to measure its thickness and the shape of bedrock below.In their analysis of the radar data, the team discovered a continuous bedrock canyon that extends from almost the center of the island and ends beneath the Petermann Glacier fjord in northern Greenland.At certain frequencies, radio waves can travel through the ice and bounce off the bedrock underneath. The amount of times the radio waves took to bounce back helped researchers determine the depth of the canyon. The longer it took, the deeper the bedrock feature.”Two things helped lead to this discovery,” said Michael Studinger, IceBridge project scientist at NASA’s Goddard Space Flight Center in Greenbelt, Md. “It was the enormous amount of data collected by IceBridge and the work of combining it with other datasets into a Greenland-wide compilation of all existing data that makes this feature appear in front of our eyes.”The researchers believe the canyon plays an important role in transporting sub-glacial meltwater from the interior of Greenland to the edge of the ice sheet into the ocean. Evidence suggests that before the presence of the ice sheet, as much as 4 million years ago, water flowed in the canyon from the interior to the coast and was a major river system.”It is quite remarkable that a channel the size of the Grand Canyon is discovered in the 21st century below the Greenland ice sheet,” said Studinger. …Read more
July 22, 2013 — Climate data can help predict some crop failures several months before harvest, according to a new study from an international team, including a research scientist at NASA’s Goddard Space Flight Center in Greenbelt, Md.Scientists found that in about one-third of global cropland, temperature and soil moisture have strong relationships to the yield of wheat and rice at harvest. For those two key crops, a computer model could predict crop failures three months in advance for about 20 percent of global cropland, according to the study, published July 21 in Nature Climate Change.”You can estimate ultimate yields according to the climatic condition several months before,” said Molly Brown, with Goddard’s Biospheric Sciences Laboratory. “From the spring conditions, the preexisting conditions, the pattern is set.”The scientists wanted to examine the reliability and timeliness of crop failure forecasts in order for governments, insurers and others to plan accordingly. The research team, led by Toshichika Iizumi with the National Institute for Agro-Environmental Sciences in Tsukuba, Japan, created and tested a new crop model, incorporating temperature and precipitation forecasts and satellite observations from 1983 to 2006. They then examined how well those data predicted the crop yield or crop failure that actually occurred at the end of each season. For example, by looking at the temperature and soil moisture in June of a given year, they were hoping to predict the success of a corn harvest in August and September.The team studied four crops — corn, soybeans, wheat and rice — but the model proved most useful for wheat and rice. Crop failures in regions of some major wheat and rice exporters, such as Australia and Uruguay, could be predicted several months in advance, according to the study. The model also forecasted some minor changes in crop yield, not just the devastating crop failures resulting from severe droughts or other weather extremes.”The impact of climate extremes — the kind of events that have a large impact on global production — is more predictable than smaller variations in climate, but even variations of 5 percent in yield were correctly simulated in the study for many parts of the globe,” said Andy Challinor, a co-author of the study and a professor with the University of Leeds in the United Kingdom.Economic factors, including agricultural technology, fertilizer, seeds and irrigation infrastructure, are key to determining how much a farmer can grow, Brown said. A farmer with costly equipment and high-yielding varieties can efficiently plant seeds and grow more productive crops than a farmer planting low-yielding varieties, one seed at a time. Farmers in the United States, for example, can grow about 10 times more corn per acre than farmers in Zimbabwe.But if economics set the bar for crop yield, other factors — including climate — can still cause variations that lead to good years and devastating years.We’re trying to bound how much the weather matters. …Read more
July 15, 2013 — NASA’s Hubble Space Telescope has discovered a new moon orbiting the distant blue-green planet Neptune, the 14th known to be circling the giant planet.The moon, designated S/2004 N 1, is estimated to be no more than 12 miles across, making it the smallest known moon in the Neptunian system. It is so small and dim that it is roughly 100 million times fainter than the faintest star that can be seen with the naked eye. It even escaped detection by NASA’s Voyager 2 spacecraft, which flew past Neptune in 1989 and surveyed the planet’s system of moons and rings.Mark Showalter of the SETI Institute in Mountain View, Calif., found the moon July 1, while studying the faint arcs, or segments of rings, around Neptune. “The moons and arcs orbit very quickly, so we had to devise a way to follow their motion in order to bring out the details of the system,” he said. “It’s the same reason a sports photographer tracks a running athlete — the athlete stays in focus, but the background blurs.”The method involved tracking the movement of a white dot that appears over and over again in more than 150 archival Neptune photographs taken by Hubble from 2004 to 2009.On a whim, Showalter looked far beyond the ring segments and noticed the white dot about 65,400 miles from Neptune, located between the orbits of the Neptunian moons Larissa and Proteus. The dot is S/2004 N 1. Showalter plotted a circular orbit for the moon, which completes one revolution around Neptune every 23 hours.The Hubble Space Telescope is a cooperative project between NASA and the European Space Agency. NASA’s Goddard Space Flight Center in Greenbelt, Md., manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore, Md., conducts Hubble science operations. STScI is operated by the Association of Universities for Research in Astronomy Inc., in Washington.For images and more information about Neptune’s new moon, visit: http://hubblesite.org/news/2013/30Read more
July 10, 2013 — NASA’s Interstellar Boundary Explorer (IBEX) spacecraft recently provided the first complete pictures of the solar system’s downwind region, revealing a unique and unexpected structure.Researchers have long theorized that, like a comet, a “tail” trails the heliosphere, the giant bubble in which our solar system resides, as the heliosphere moves through interstellar space. The first IBEX images released in 2009 showed an unexpected ribbon of surprisingly high energetic neutral atom (ENA) emissions circling the upwind side of the solar system. With the collection of additional ENAs over the first year of observations, a structure dominated by lower energy ENAs emerged, which was preliminarily identified as the heliotail. However, it was quite small and appeared to be offset from the downwind direction, possibly because of interactions from the galaxy’s external magnetic field.As the next two years of IBEX data filled in the observational hole in the downwind direction, researchers found a second tail region to the side of the previously identified one. The IBEX team reoriented the IBEX maps and two similar, low-energy ENA structures became clearly visible straddling the downwind direction of the heliosphere, indicating structures that better resemble “lobes” than a single unified tail.”We chose the term ‘lobes’ very carefully,” says Dr. Dave McComas, IBEX principal investigator and assistant vice president of the Space Science and Engineering Division at Southwest Research Institute. “It may well be that these are separate structures bent back toward the downwind direction. However, we can’t say that for certain with the data we have today.”The team adopted the nautical terms port and starboard to distinguish the lobes, as the heliosphere is the “vessel” that transports our solar system throughout the galaxy.IBEX data show the heliotail is the region where the Sun’s million mile per hour solar wind flows down and ultimately escapes the heliosphere, slowly evaporating because of charge exchange. The slow solar wind heads down the tail in the port and starboard lobes at low- and mid-latitudes and, at least around the Sun’s minimum in solar activity, fast solar wind flows down it at high northern and southern latitudes.”We’re seeing a heliotail that’s much flatter and broader than expected, with a slight tilt,” says McComas. “Imagine sitting on a beach ball. …Read more
June 25, 2013 — Hungry people are often difficult to deal with. A good meal can affect more than our mood, it can also influence our willingness to take risks. This phenomenon is also apparent across a very diverse range of species in the animal kingdom. Experiments conducted on the fruit fly, Drosophila, by scientists at the Max Planck Institute of Neurobiology in Martinsried have shown that hunger not only modifies behaviour, but also changes pathways in the brain.Animal behaviour is radically affected by the availability and amount of food. Studies prove that the willingness of many animals to take risks increases or declines depending on whether the animal is hungry or full. For example, a predator only hunts more dangerous prey when it is close to starvation. This behaviour has also been documented in humans in recent years: one study showed that hungry subjects took significantly more financial risks than their sated colleagues.Also the fruit fly, Drosophila, changes its behaviour depending on its nutritional state. The animals usually perceive even low quantities of carbon dioxide to be a sign of danger and opt to take flight. However, rotting fruit and plants — the flies’ main sources of food — also release carbon dioxide. Neurobiologists in Martinsried have now discovered how the brain deals with this constant conflict in deciding between a hazardous substance and a potential food source taking advantage of the fly as a great genetic model organism for circuit neuroscience.In various experiments, the scientists presented the flies with environments containing carbon dioxide or a mix of carbon dioxide and the smell of food. …Read more
June 3, 2013 — When it comes to saving its own hide, the tiger moth can predict the future.A new study by researchers at Wake Forest University shows Bertholdia trigona, a species of tiger moth found in the Arizona desert, can tell if an echo-locating bat is going to attack it well before the predator swoops in for the kill — making the intuitive, tiny-winged insect a master of self-preservation.Predators in the nightA bat uses sonar to hunt at night. The small mammal emits a series of ultrasonic cries and listens carefully to the echoes that return. By determining how long it takes the sound to bounce back, the bat can figure out how far away its prey is.Aaron Corcoran and William Conner of Wake Forest previously discovered Bertholdia trigona defends itself by jamming its predators’ sonar. Conner, a professor of biology, said the tiger moth has a blister of cuticle on either side of its thorax called a tymbal. It flexes this structure to create a high-pitched, clicking sound.The moth emits more than 4,500 clicks per second right when the bat would normally attack, jamming its sonar.”It is the only animal in the world we know of that can jam its predator’s sonar,” Conner said. “Bats and tiger moths are in the midst of an evolutionary arms race.”The new study published May 6 in the journal PLOS ONE, shows that tiger moths can tell when it is time to start clicking by listening for a telltale change in the repetition rate of the bat’s cries and an increase in sound intensity. The combination of these two factors tells the moth that it has been targeted.Conner’s team used high-speed infrared cameras to create 3D maps of the flight paths of bats attacking tiger moths. They then used an ultrasonic microphone to measure the rate of bat cries and moth clicks.Normally, a bat attack starts with relatively intermittent cries. As it gets closer to the moth, a bat increases the rate at which it produces cries — painting a clearer picture of the moth’s location.Conner’s team found that soon after the bats detected and targeted their prey, moths increased their rate of clicking dramatically, causing the predators to veer off course. The sonar jamming works 93 percent of the time. …Read more
May 29, 2013 — Medical emergencies during commercial airline travel can be a frightening experience, but most situations are well-treated by other passengers and flight attendants, in collaboration with consulting physicians on the ground. A University of Pittsburgh study to be published in the May 30 issue of the New England Journal of Medicine found that doctors, nurses and other medical professionals on the aircraft helped to treat sick fellow passengers in three-fourths of the emergencies studied.
Led by Christian Martin-Gill, M.D., M.P.H., assistant professor of emergency medicine, Department of Emergency Medicine, University of Pittsburgh School of Medicine, the study examined records of in-flight medical calls from five domestic and international airlines to UPMC’s STAT-MD Communications Center, a 24-hour, physician-directed medical command center, from Jan. 1, 2008, through Oct. 31, 2010. Although not required to by the Federal Aviation Administration (FAA), many airlines use a medical communications facility to consult with physicians on the ground. STAT-MD handled 11,920 in-flight medical calls during the study period. The most common in-flight problems reported were syncope (fainting) or near-syncope, respiratory symptoms, nausea or vomiting, and cardiac symptoms.
Physician passengers provided medical assistance in nearly half of those calls, according to the researchers. Other medical professionals, such as nurses and emergency medical technicians, provided help in another 28 percent of the calls. Flights were diverted to alternate destinations because of medical concerns in only 7.3 percent of the incidents.
Most of the passengers who were treated in-flight had favorable outcomes. According to data for nearly 11,000 of those patients, 25.8 percent were transported to a hospital by emergency medical services; 8.6 percent were admitted, and 0.3 percent died, either on board the aircraft or upon transport to the hospital. The most common causes for admission to a hospital were stroke, respiratory and cardiac symptoms.
The study found that most calls could be managed by the flight attendants, who are trained in emergency protocols and have access to an FAA-required emergency medical kit, along with medical volunteers in the majority of cases. In these cases, ground-based physician consultants provided additional guidance, including use of specific medications in the kit, and assisting the pilot and crew in making decisions regarding need for diversion of the aircraft.
“We wanted to provide a description of the type of emergencies commonly treated on an aircraft, identify the outcomes of these patients and provide an understanding of the treatment capabilities available on the aircraft in the medical kit and through experts on the ground,” said Dr. Martin-Gill.
The researchers suggest physicians and others obtain a basic knowledge and awareness of the resources available to them in this unfamiliar and cramped setting to be effective volunteers during an in-flight emergency.
“Commercial air travel is generally safe, and in-flight deaths are rare,” said Dr. Martin-Gill. “We hope to look more closely at the most common conditions and which ones require follow-up care so we can better tailor treatment recommendations for passengers.”
Co-authors of the paper include Drew Peterson, M.D., Francis Guyette, M.D., M.P.H., Adam Tobias, M.D., M.P.H., Catherine McCarthy, B.S., Scott Harrington, M.D., Theodore Delbridge, M.D., M.P.H., and Donald Yealy, M.D., through the Department of Emergency Medicine, University of Pittsburgh School of Medicine.
The work was funded by National Institutes of Health grants UL1 RR024153 and UL1 TR000005.Read more