Four new species of 'legless lizards' discovered living on the edge
The Bakersfield legless lizard, (Anniella grinnelli), which today ranges from downtown Bakersfield in the southern San Joaquin Valley to the Carrizo Plain National Monument 30 miles to the west. The species has a purple belly and yellow sides. Credit: Alex Krohn
California biologists have discovered four new species of reclusive legless lizards living in some of the most marginal habitat in the state: a vacant lot in downtown Bakersfield, among oil derricks in the lower San Joaquin Valley, on the margins of the Mojave desert, and at the end of one of the runways at LAX.
"This shows that there is a lot of undocumented biodiversity within California," said Theodore Papenfuss, a reptile and amphibian expert, or herpetologist, with UC Berkeley's Museum of Vertebrate Zoology, who discovered and identified the new specieswith James Parham of California State University, Fullerton. The discoveries raise the number of California legless lizard species from one to five.
The herpetologists named the new snake-like lizards after four legendary UC Berkeley scientists: museum founder Joseph Grinnell, paleontologist Charles Camp, philanthropist and amateur scientist Annie Alexander and herpetologist Robert C. Stebbins, at 98 the only one of the group still alive.
"These are animals that have existed in the San Joaquin Valley, separate from any other species, for millions of years, completely unknown," said Parham, who obtained his doctorate from Berkeley and is now curator of paleontology at the John D. Cooper Archaeology and Paleontology Center. "If you want to preserve biodiversity, it is the really distinct species like these that you want to preserve."
Papenfuss and Parham reported their discovery on Sept. 17 in the journal Breviora, a publication of the Museum of Comparative Zoology at Harvard University.
Legless lizards, represented by more than 200 species worldwide, are well-adapted to life in loose soil, Papenfuss said. Millions of years ago, lizards on five continents independently lost their limbs in order to burrow more quickly into sand or soil, wriggling like snakes. Some still have vestigial legs. Though up to eight inches in length, the creatures are seldom seen because they live mostly underground, eating insects and larvae, and may spend their lives within an area the size of a dining table. Most are discovered in moist areas when people overturn logs or rocks.
Legless lizards like this purple-bellied A. grinnelli lost their legs millions of years ago in order to burrow more quickly into loose soil and sand.
Herping the Central Valley
For the past 15 years, Papenfuss and Parham have scoured the state for new species, suspecting that the fairly common California legless lizard (Anniella pulchra), the only legless lizard in the U.S. West, had at least some relatives. They discovered one new species – yellow-bellied like its common cousin – under leaf litter in protected dunes west of Los Angeles International Airport. They named that species A. stebbinsi, because Stebbins grew up and developed an early interest in natural history in the nearby Santa Monica Mountains.
Because many sandy, loamy areas, including dunes and desert areas, offer little cover for lizards if they emerge, Papenfuss distributed thousands of pieces of cardboard throughout the state in areas likely to host the lizard. He returned year after year to see if lizards were using the moist, cool areas under the cardboard as resting or hunting grounds.
This technique turned up three other new species in the Central Valley: A. alexanderae, named after Annie Alexander, who endowed the UC Berkeley museum in 1908 and added 20,000 specimens to its collections; A. campi after Charles Camp, because of his early-career discovery of the Mt. Lyell salamander in the Sierra; and A. grinnelli after Joseph Grinnell, who in 1912 first noted habitat destruction around Bakersfield from agriculture and oil drilling.
Interestingly, all these species had been collected before and were in collections around California, but when preserved in alcohol, the lizards lose their distinctive color and look identical. Papenfuss and Parham identified the species through genetic profiling, but they subsequently found ways to distinguish them from one another via belly color, number and arrangement of scales, and number of vertebrae. However, two species – the previously known common legless lizard of Northern California and the newly named southern species found at LAX and apparently broadly distributed south of the Tehachapi Mountains – remain indistinguishable except by genetic tests or, now, the location where they are found.
Distribution of the five species of legless lizard in California. A. pulchra was already known from a wide range in the central part of the state, but four others are newly described by UC Berkeley & Cal State-Fullerton herpetologists. Credit: Breviora
Species of special concern
Papenfuss and Parham are working with the California Department of Fish and Wildlife (CDFW) to determine whether the lizards need protected status. Currently, the common legless lizard is listed by the state as a species of special concern.
"These species definitely warrant attention, but we need to do a lot more surveys in California before we can know whether they need higher listing," Parham said.
Papenfuss noted that two of the species are within the range of the blunt-nosed leopard lizard, which is listed as an endangered species by both the federal and state governments.
"On one hand, there are fewer legless lizards than leopard lizards, so maybe these two new species should be given special protection," he said. "On the other hand, there may be ways to protect their habitat without establishing legal status. They don't need a lot of habitat, so as long as we have some protected sites, they are probably OK."
Papenfuss says they are not yet in danger of going extinct, since he has found some of the lizards in protected reserves operated by the CDFW, the U.S. Bureau of Land Management and a private water reserve outside Bakersfield, in addition to the El Segundo Dunes near LAX.
Big Bang was mirage from collapsing higher-dimensional star, theorists propose.
It could be time to bid the Big Bang bye-bye. Cosmologists have speculated that the Universe formed from the debris ejected when a four-dimensional star collapsed into a black hole — a scenario that would help to explain why the cosmos seems to be so uniform in all directions.
The standard Big Bang model tells us that the Universe exploded out of an infinitely dense point, or singularity. But nobody knows what would have triggered this outburst: the known laws of physics cannot tell us what happened at that moment.
“For all physicists know, dragons could have come flying out of the singularity,” says Niayesh Afshordi, an astrophysicist at the Perimeter Institute for Theoretical Physics in Waterloo, Canada.It is also difficult to explain how a violent Big Bang would have left behind a Universe that has an almost completely uniform temperature, because there does not seem to have been enough time since the birth of the cosmos for it to have reached temperature equilibrium.
To most cosmologists, the most plausible explanation for that uniformity is that, soon after the beginning of time, some unknown form of energy made the young Universe inflate at a rate that was faster than the speed of light. That way, a small patch with roughly uniform temperature would have stretched into the vast cosmos we see today. But Afshordi notes that “the Big Bang was so chaotic, it’s not clear there would have been even a small homogenous patch for inflation to start working on”.
On the brane
In a paper posted last week on the arXiv preprint server1, Afshordi and his colleagues turn their attention to a proposal2 made in 2000 by a team including Gia Dvali, a physicist now at the Ludwig Maximilians University in Munich, Germany. In that model, our three-dimensional (3D) Universe is a membrane, or brane, that floats through a ‘bulk universe’ that has four spatial dimensions.
Ashfordi's team realized that if the bulk universe contained its own four-dimensional (4D) stars, some of them could collapse, forming 4D black holes in the same way that massive stars in our Universe do: they explode as supernovae, violently ejecting their outer layers, while their inner layers collapse into a black hole.
In our Universe, a black hole is bounded by a spherical surface called an event horizon. Whereas in ordinary three-dimensional space it takes a two-dimensional object (a surface) to create a boundary inside a black hole, in the bulk universe the event horizon of a 4D black hole would be a 3D object — a shape called a hypersphere. When Afshordi’s team modelled the death of a 4D star, they found that the ejected material would form a 3D brane surrounding that 3D event horizon, and slowly expand.
The authors postulate that the 3D Universe we live in might be just such a brane — and that we detect the brane’s growth as cosmic expansion. “Astronomers measured that expansion and extrapolated back that the Universe must have begun with a Big Bang — but that is just a mirage,” says Afshordi.
Model discrepancy
The model also naturally explains our Universe’s uniformity. Because the 4D bulk universe could have existed for an infinitely long time in the past, there would have been ample opportunity for different parts of the 4D bulk to reach an equilibrium, which our 3D Universe would have inherited.
The picture has some problems, however. Earlier this year, the European Space Agency's Planck space observatory released data that mapped the slight temperature fluctuations in the cosmic microwave background — the relic radiation that carries imprints of the Universe’s early moments. The observed patterns matched predictions made by the standard Big Bang model and inflation, but the black-hole model deviates from Planck's observations by about 4%. Hoping to resolve the discrepancy, Afshordi says that his is now refining its model.
Despite the mismatch, Dvali praises the ingenious way in which the team threw out the Big Bang model. “The singularity is the most fundamental problem in cosmology and they have rewritten history so that we never encountered it,” he says. Whereas the Planck results “prove that inflation is correct”, they leave open the question of how inflation happened, Dvali adds. The study could help to show how inflation is triggered by the motion of the Universe through a higher-dimensional reality, he says.
Evolutionary medicine of skin cancer risk among Europeans
Trade-offs for fair skin
The proclivity of Spaniards to bask in regions like the Costa del Sol while their northern European counterparts must stay under cover to protect their paler skin or risk skin cancer is due in large part to the pigment producing qualities of the MC1R gene locus. The MC1R gene, expressed in skin and hair follicle cells, is more diverse in Eurasian populations compared to African populations.
Now, a team of researchers led by Santos Alonso, et. al., have examined the evolutionary selective pressure for MC1R among a large population of Spaniards in comparison to their Northern Europeans counterparts as well as individuals with melanoma. Using data from the 1,000 Genomes Project as well as samples from different regions of Spain, they authors show that selection for the MC1R locus is strong in South Europeans, but not the case for Northern Europeans.
Two evolutionary selective processes seem to be acting on MC1R in Southern Europeans. On the one hand, there is selective pressure to maintain at high frequencies the ancestral form of the gene, also the one most common in Africans. But simultaneously, one gene variant seems to be favored in South Europeans. This gene variant, called the V60L allele, has been associated before with red/blond hair and fair skin.
World frequency distribution of V60L is confined mostly to Europe and the Near East but mostly absent in East Asia and Africa, indicating that the first appearance of V60L mutation occurred some time after modern humans left Africa but before dispersal throughout Europe. Fair skin depigmentation could be a useful change for the adaptation of humans to this new environment. Traditionally, depigmentation had been hypothetically explained as a function of the need of humans to synthesize vitamin D in areas of reduced sun light (compared to Africa). "We have not proved that this is the underlying reason for the signature of positive selection on V60L, but our data adds support to this view, although this point needs to be further explored" says Santos Alonso, senior author of the paper.
Interestingly, the same allele V60L has been associated to increased risk of melanoma, the most dangerous of skin cancers. This indicates", says Saioa López, one of the two main authors of the paper, "that the increase in fitness for the population as a consequence of depigmentation has had a collateral damage consequence for the individual´s health. This can be reconciled if we assume that melanoma is typically a post-reproductive disease, and consequently should have little effect on the individual's genetic contribution to the next generation. It constitutes a kind of evolutionary 'buy now pay later' trade-off.'"
Microbial battery: Team uses 'wired microbes' to generate electricity from sewage
Engineers at Stanford University have devised a new way to generate electricity from sewage using naturally-occurring "wired microbes" as mini power plants, producing electricity as they digest plant and animal waste.
In a paper published today in the Proceedings of the National Academy of Sciences, co-authors Yi Cui, a materials scientist, Craig Criddle, an environmental engineer, and Xing Xie, an interdisciplinary fellow, call their invention a microbial battery.
At the moment, however, their laboratory prototype is about the size of a D-cell battery and looks like a chemistry experiment, with two electrodes, one positive, the other negative, plunged into a bottle of wastewater.
Inside that murky vial, attached to the negative electrode like barnacles to a ship's hull, an unusual type of bacteria feast on particles of organic waste and produce electricity that is captured by the battery's positive electrode.
"We call it fishing for electrons," said Criddle, a professor in the department of civil and environmental engineering.
Scientists have long known of the existence of what they call exoelectrogenic microbes – organisms that evolved in airless environments and developed the ability to react with oxide minerals rather than breathe oxygen as we do to convert organic nutrients into biological fuel.
The release describes nature of these microbes; more than 100 can fit side by side in the width of a human hair; the microbes are white tubes; they are attached to the carbon filaments of the battery; the tendrils are the "wires" referred to; …more
During the past dozen years or so, several research groups have tried various ways to use these microbes as bio-generators, but tapping this energy efficiently has proven challenging.
What is new about the microbial battery is a simple yet efficient design that puts these exoelectrogenic bacteria to work.
At the battery's negative electrode, colonies of wired microbes cling to carbon filaments that serve as efficient electrical conductors. Using a scanning electron microscope, the Stanford team captured images of these microbes attaching milky tendrils to the carbon filaments.
"You can see that the microbes make nanowires to dump off their excess electrons," Criddle said. To put the images into perspective, about 100 of these microbes could fit, side by side, in the width of a human hair.
As these microbes ingest organic matter and convert it into biological fuel, their excess electrons flow into the carbon filaments and across to the positive electrode, which is made of silver oxide, a material that attracts electrons.
The electrons flowing to the positive node gradually reduce the silver oxide to silver, storing the spare electrons in the process. According to Xie, after a day or so the positive electrode has absorbed a full load of electrons and has largely been converted into silver.
At that point it is removed from the battery and re-oxidized back to silver oxide, releasing the stored electrons.
The release describes nature of these microbes; more than 100 can fit side by side in the width of a human hair; the microbes are white tubes; they are attached to the carbon filaments of the battery; the tendrils are the "wires" referred to; …more
The Stanford engineers estimate that the microbial battery can extract about 30 percent of the potential energy locked in wastewater. That is roughly the same efficiency at which the best commercially available solar cells convert sunlight into electricity.
Of course, there is far less energy potential in wastewater. Even so, the inventors say the microbial battery is worth pursuing because it could offset some of the electricity now use to treat wastewater. That use currently accounts for about three percent of the total electrical load in developed nations. Most of this electricity goes toward pumping air into wastewater at conventional treatment plants where ordinary bacteria use oxygen in the course of digestion, just like humans and other animals.
Looking ahead, the Stanford engineers say their biggest challenge will be finding a cheap but efficient material for the positive node.
"We demonstrated the principle using silver oxide, but silver is too expensive for use at large scale," said Cui, an associate professor of materials science and engineering. "Though the search is underway for a more practical material, finding a substitute will take time."
Philosophers and scientists have long puzzled over where human imagination comes from. In other words, what makes humans able to create art, invent tools, think scientifically and perform other incredibly diverse behaviors?
The answer, Dartmouth researchers conclude in a new study, lies in a widespread neural network -- the brain's "mental workspace" -- that consciously manipulates images, symbols, ideas and theories and gives humans the laser-like mental focus needed to solve complex problems and come up with new ideas.
Their findings, titled "Network structure and dynamics of the mental workspace," appear the week of Sept. 16 in theProceedings of the National Academy of Sciences.
"Our findings move us closer to understanding how the organization of our brains sets us apart from other species and provides such a rich internal playground for us to think freely and creatively," says lead author Alex Schlegel , a graduate student in the Department of Psychological and Brain Sciences. "Understanding these differences will give us insight into where human creativity comes from and possibly allow us to recreate those same creative processes in machines."
Scholars theorize that human imagination requires a widespread neural network in the brain, but evidence for such a "mental workspace" has been difficult to produce with techniques that mainly study brain activity in isolation. Dartmouth researchers addressed the issue by asking: How does the brain allow us to manipulate mental imagery? For instance, imagining a bumblebee with the head of a bull, a seemingly effortless task but one that requires the brain to construct a totally new image and make it appear in our mind's eye.
In the study, 15 participants were asked to imagine specific abstract visual shapes and then to mentally combine them into new more complex figures or to mentally dismantle them into their separate parts. Researchers measured the participants' brain activity with functional MRI and found a cortical and subcortical network over a large part of the brain was responsible for their imagery manipulations. The network closely resembles the "mental workspace" that scholars have theorized might be responsible for much of human conscious experience and for the flexible cognitive abilities that humans have evolved.
Journal Reference:
Alexander Schlegel, Peter J. Kohler, Sergey V. Fogelson, Prescott Alexander, Dedeepya Konuthula, and Peter Ulric Tse. Network structure and dynamics of the mental workspace. PNAS, September 16, 2013 DOI:10.1073/pnas.1311149110
"The ability to perceive time on very small scales may be the difference between life and death for fast-moving organisms such as predators and their prey," said lead author Kevin Healy, at Trinity College Dublin (TCD), Ireland.
The reverse was found in bigger animals, which may miss things that smaller creatures can rapidly spot.
Speedy goalkeeper
In humans, too, there is variation among individuals. Athletes, for example, can often process visual information more quickly. An experienced goalkeeper would therefore be quicker than others in observing where a ball comes from.
The speed at which humans absorb visual information is also age-related, said Andrew Jackson, a co-author of the work at TCD.
"Younger people can react more quickly than older people, and this ability falls off further with increasing age."
The team looked at the variation of time perception across a variety of animals. They gathered datasets from other teams who had used a technique called critical flicker fusion frequency, which measures the speed at which the eye can process light.
Plotting these results on a graph revealed a pattern that showed a strong relationship between body size and how quick the eye could respond to changing visual information such as a flashing light.
"From a human perspective, our ability to process visual information limits our ability to drive cars or fly planes any faster than we currently do in Formula 1, where these guys are pushing the limits of what is humanly possible," Dr Jackson told BBC News.
"Therefore, to go any quicker would require either computer assistance, or enhancement of our visual system, either through drugs or ultimately implants."
Confused woodlice
The current study focused on vertebrates, but the team also found that several fly species have eyes that react to stimulus more than four times quicker than the human eye.
The common European eel, the leatherback turtle, and the blacknose shark had the slowest visual systems
Although the eel and blacknose shark are relatively small, they have slow metabolisms which explains their slow visual systems
The leatherback is a huge turtle that feeds primarily on slow moving jellyfish and has a very slow metabolism itself, so doesn't need to invest in high visual processing equipment
But some deep-sea isopods (a type of marine woodlouse) have the slowest recorded reaction of all, and can only see a light turning off and on four times per second "before they get confused and see it as being constantly on", Dr Jackson explained.
"We are beginning to understand that there is a whole world of detail out there that only some animals can perceive and it's fascinating to think of how they might perceive the world differently to us," he added.
Graeme Ruxton, of the University of St Andrews, Scotland, another co-author, said: "Having eyes that send updates to the brain at much higher frequencies than our eyes do is of no value if the brain cannot process that information equally quickly.
"Hence, this work highlights the impressive capabilities of even the smallest animal brains. Flies might not be deep thinkers but they can make good decisions very quickly."
A Chinese man has grown a new nose on his forehead.
Astonishing images showing what may be the most extreme nose job yet,have revealed Xiaolian at a hospital in Fuzhou, Fujian province, as doctors check on his progress ahead of transplant surgery.
The 22-year-old had the extreme treatment after his original nose was infected and left deformed after a traffic accident.
The infection had corroded the cartilage of the nose making it impossible for surgeons to fix.
It left no alternative but to grow a new nose as a replacement.
Xiaolian neglected his nasal trauma following a traffic accident
Doctors at a hospital in Fuzhou, Fujian province placed a skin tissue expander onto Xiaolian's forehead and cut it into the shape of a nose.
A Chinese man has grown a new nose on his forehead.
They then planted cartilage taken from his ribs to mould the nose.
The surgeons said the new nose is in good shape and the transplant surgery could be performed soon, local media reported.
Birds originated from a group of small, meat-eating theropod dinosaurs called maniraptorans sometime around 150 million years ago. Recent findings from around the world show that many maniraptorans were very bird-like, with feathers, hollow bones, small body sizes and high metabolic rates.
But the question remains, at what point did forelimbs evolve into wings – making it possible to fly?
McGill University professor Hans Larsson and a former graduate student, Alexander Dececchi, set out to answer that question by examining fossil data, greatly expanded in recent years, from the period marking the origin of birds.
In a study published in the September issue of Evolution, Larsson and Dececchi find that throughout most of the history of carnivorous dinosaurs, limb lengths showed a relatively stable scaling relationship to body size. This is despite a 5000-fold difference in mass between Tyrannosaurus rex and the smallest feathered theropods from China. This limb scaling changed, however, at the origin of birds, when both the forelimbs and hind limbs underwent a dramatic decoupling from body size. This change may have been critical in allowing early birds to evolve flight, and then to exploit the forest canopy, the authors conclude.
As forelimbs lengthened, they became long enough to serve as an airfoil, allowing for the evolution of powered flight. When coupled with the shrinking of the hind limbs, this helped refine flight control and efficiency in early birds. Shorter legs would have aided in reducing drag during flight -- the reason modern birds tuck their legs as they fly -- and also in perching and moving about on small branches in trees. This combination of better wings with more compact legs would have been critical for the survival of birds in a time when another group of flying reptiles, the pterosaurs, dominated the skies and competed for food.
How birds got their wings
“Our findings suggest that birds underwent an abrupt change in their developmental mechanisms, such that their forelimbs and hind limbs became subject to different length controls,” says Larsson, Canada Research Chair in Macroevolution at McGill’s Redpath Museum. Deviations from the rules of how an animal’s limbs scale with changes in body size -- another example is the relatively long legs and short arms of humans -- usually indicate some major shift in function or behaviour. “This decoupling may be fundamental to the success of birds, the most diverse class of land vertebrates on Earth today.”
“The origin of birds and powered flight is a classic major evolutionary transition,” says Dececchi, now a postdoctoral researcher at the University of South Dakota. “Our findings suggest that the limb lengths of birds had to be dissociated from general body size before they could radiate so successfully. It may be that this fact is what allowed them to become more than just another lineage of maniraptorans and led them to expand to the wide range of limb shapes and sizes present in today’s birds.”
“This work, coupled with our previous findings that the ancestors of birds were not tree dwellers, does much to illuminate the ecology of bird antecedents.” says Dr. Dececchi. “Knowing where birds came from, and how they got to where they are now, is crucial for understanding how the modern world came to look the way it is.”
Funding for the research was provided by the Fonds de recherche du Québec - Nature et technologies, the Canada Research Chairs program, and the National Sciences and Engineering Research Council of Canada.
Physicists have discovered a jewel-like geometric object that dramatically simplifies calculations of particle interactions and challenges the notion that space and time are fundamental components of reality.
“This is completely new and very much simpler than anything that has been done before,” said Andrew Hodges, a mathematical physicist at Oxford University who has been following the work.
The revelation that particle interactions, the most basic events in nature, may be consequences of geometry significantly advances a decades-long effort to reformulate quantum field theory, the body of laws describing elementary particles and their interactions. Interactions that were previously calculated with mathematical formulas thousands of terms long can now be described by computing the volume of the corresponding jewel-like “amplituhedron,” which yields an equivalent one-term expression.
“The degree of efficiency is mind-boggling,” said Jacob Bourjaily, a theoretical physicist at Harvard University and one of the researchers who developed the new idea. “You can easily do, on paper, computations that were infeasible even with a computer before.”
The new geometric version of quantum field theory could also facilitate the search for a theory of quantum gravity that would seamlessly connect the large- and small-scale pictures of the universe. Attempts thus far to incorporate gravity into the laws of physics at the quantum scale have run up against nonsensical infinities and deep paradoxes. The amplituhedron, or a similar geometric object, could help by removing two deeply rooted principles of physics: locality and unitarity.
“Both are hard-wired in the usual way we think about things,” said Nima Arkani-Hamed, a professor of physics at the Institute for Advanced Study in Princeton, N.J., and the lead author of the new work, which he is presenting in talks and in a forthcoming paper. “Both are suspect.”
Locality is the notion that particles can interact only from adjoining positions in space and time. And unitarity holds that the probabilities of all possible outcomes of a quantum mechanical interaction must add up to one. The concepts are the central pillars of quantum field theory in its original form, but in certain situations involving gravity, both break down, suggesting neither is a fundamental aspect of nature.
In keeping with this idea, the new geometric approach to particle interactions removes locality and unitarity from its starting assumptions. The amplituhedron is not built out of space-time and probabilities; these properties merely arise as consequences of the jewel’s geometry. The usual picture of space and time, and particles moving around in them, is a construct.
“It’s a better formulation that makes you think about everything in a completely different way,” said David Skinner, a theoretical physicist at Cambridge University.
The amplituhedron itself does not describe gravity. But Arkani-Hamed and his collaborators think there might be a related geometric object that does. Its properties would make it clear why particles appear to exist, and why they appear to move in three dimensions of space and to change over time.
Because “we know that ultimately, we need to find a theory that doesn’t have” unitarity and locality, Bourjaily said, “it’s a starting point to ultimately describing a quantum theory of gravity.”
Clunky Machinery
The amplituhedron looks like an intricate, multifaceted jewel in higher dimensions. Encoded in its volume are the most basic features of reality that can be calculated, “scattering amplitudes,” which represent the likelihood that a certain set of particles will turn into certain other particles upon colliding. These numbers are what particle physicists calculate and test to high precision at particle accelerators like the Large Hadron Collider in Switzerland.
With two diminutive legs locked into a leap-ready position, the tiny jumper bends its body taut like an archer drawing a bow. At the top of its legs, a minuscule pair of gears engage—their strange, shark-fin teeth interlocking cleanly like a zipper. And then, faster than you can blink, think, or see with the naked eye, the entire thing is gone. In 2 milliseconds it has bulleted skyward, accelerating at nearly 400 g's—a rate more than 20 times what a human body can withstand. At top speed the jumper breaks 8 mph—quite a feat considering its body is less than one-tenth of an inch long.
This miniature marvel is an adolescent issus, a kind of planthopper insect and one of the fastest accelerators in the animal kingdom. As a duo of researchers in the U.K. report today in the journal Science, the issus also the first living creature ever discovered to sport a functioning gear. "Jumping is one of the most rapid and powerful things an animal can do," says Malcolm Burrows, a zoologist at the University of Cambridge and the lead author of the paper, "and that leads to all sorts of crazy specializations."
The researchers believe that the issus—which lives chiefly on European climbing ivy—evolved its acrobatic prowess because it needs to flee dangerous situations. Although they're not exactly sure if the rapid jump evolved to escape hungry birds, parasitizing wasps, or the careless mouths of large grazing animals, "there's been enormous evolutionary pressure to become faster and faster, and jump further and further away," Burrows says. But gaining this high acceleration has put incredible demands on the reaction time of insect's body parts, and that's where the gears—which "you can imagine being at the top of the thigh bone in a human," Burrows says—come in.
A scanning electron micrograph image of the gears. Credit: Malcolm Burrows
"As the legs unfurl to power the jump," Burrows says, "both have to move at exactly the same time. If they didn't, the animal would start to spiral out of control." Larger animals, whether kangaroos or NBA players, rely on their nervous system to keep their legs in sync when pushing off to jump—using a constant loop of adjustment and feedback. But for the issus, their legs outpace their nervous system. By the time the insect has sent a signal from its legs to its brain and back again, roughly 5 or 6 milliseconds, the launch has long since happened. Instead, the gears, which engage before the jump, let the issus lock its legs together—synchronizing their movements to a precision of 1/300,000 of a second.
The gears themselves are an oddity. With gear teeth shaped like cresting waves, they look nothing like what you'd find in your car or in a fancy watch. (The style that you're most likely familiar with is called an involute gear, and it was designed by the Swiss mathematician Leonhard Euler in the 18th century.) There could be two reasons for this. Through a mathematical oddity, there is a limitless number of ways to design intermeshing gears. So, either nature evolved one solution at random, or, as Gregory Sutton, coauthor of the paper and insect researcher at the University of Bristol, suspects, the shape of the issus's gear is particularly apt for the job it does. It's built for "high precision and speed in one direction," he says. "It's a prototype for a new type of gear."
Another odd thing about this discovery is that although there are many jumping insects like the issus—including ones that are even faster and better jumpers—the issus is apparently the only one with natural gears. Most other bugs synchronize the quick jolt of their leaping legs through friction, using bumpy or grippy surfaces to press the top of their legs together, says Duke University biomechanics expert Steve Vogel, who was not involved in this study. Like gears, this ensures the legs move at the same rate, but without requiring a complicated interlocking mechanism. "There are a lot of friction pads around, and they accomplish pretty much of the same thing," he says. "So I wonder what extra capacity these gears confer. They're rather specialized, and there are lots of other jumpers that don't have them, so there must be some kind of advantage."
Even stranger is that the issus doesn't keep these gears throughout its life cycle. As the adolescent insect grows, it molts half a dozen times, upgrading its exoskeleton (gears included) for larger and larger versions. But after its final molt into adulthood—poof, the gears are gone. The adult syncs its legs by friction like all the other planthoppers. "I'm gobsmacked," says Sutton. "We have a hypothesis as to why this is the case, but we can't tell you for sure."
Their idea: If one of the gear teeth were to slip and break in an adult (the researchers observed this in adolescent bugs), its jumping ability would be hindered forever. With no more molts, it would have no chance to grow more gears. And with every bound, "the whole system might slip, accelerating damage to the rest of the gear teeth," Sutton says. "Just like if your car has a gear train missing a tooth. Every time you get to that missing tooth, the gear train jerks."
NASA Spacecraft Embarks on Historic Journey Into Interstellar Space
The Space Between: This artist's concept shows the Voyager 1 spacecraft entering the space between stars. Interstellar space is dominated by plasma, ionized gas (illustrated here as brownish haze), that was thrown off by giant stars millions of years ago. Image credit: NASA/JPL-Caltech
PASADENA, Calif. -- NASA's Voyager 1 spacecraft officially is the first human-made object to venture into interstellar space. The 36-year-old probe is about 12 billion miles (19 billion kilometers) from our sun.
New and unexpected data indicate Voyager 1 has been traveling for about one year through plasma, or ionized gas, present in the space between stars. Voyager is in a transitional region immediately outside the solar bubble, where some effects from our sun are still evident. A report on the analysis of this new data, an effort led by Don Gurnett and the plasma wave science team at the University of Iowa, Iowa City, is published in Thursday's edition of the journal Science.
"Now that we have new, key data, we believe this is mankind's historic leap into interstellar space," said Ed Stone, Voyager project scientist based at the California Institute of Technology, Pasadena. "The Voyager team needed time to analyze those observations and make sense of them. But we can now answer the question we've all been asking -- 'Are we there yet?' Yes, we are."
Voyager 1 first detected the increased pressure of interstellar space on the heliosphere, the bubble of charged particles surrounding the sun that reaches far beyond the outer planets, in 2004. Scientists then ramped up their search for evidence of the spacecraft's interstellar arrival, knowing the data analysis and interpretation could take months or years.
Voyager 1 does not have a working plasma sensor, so scientists needed a different way to measure the spacecraft's plasma environment to make a definitive determination of its location. A coronal mass ejection, or a massive burst of solar wind and magnetic fields, that erupted from the sun in March 2012 provided scientists the data they needed. When this unexpected gift from the sun eventually arrived at Voyager 1's location 13 months later, in April 2013, the plasma around the spacecraft began to vibrate like a violin string. On April 9, Voyager 1's plasma wave instrument detected the movement. The pitch of the oscillations helped scientists determine the density of the plasma. The particular oscillations meant the spacecraft was bathed in plasma more than 40 times denser than what they had encountered in the outer layer of the heliosphere. Density of this sort is to be expected in interstellar space.
The plasma wave science team reviewed its data and found an earlier, fainter set of oscillations in October and November 2012. Through extrapolation of measured plasma densities from both events, the team determined Voyager 1 first entered interstellar space in August 2012.
"We literally jumped out of our seats when we saw these oscillations in our data -- they showed us the spacecraft was in an entirely new region, comparable to what was expected in interstellar space, and totally different than in the solar bubble," Gurnett said. "Clearly we had passed through the heliopause, which is the long-hypothesized boundary between the solar plasma and the interstellar plasma."
The new plasma data suggested a timeframe consistent with abrupt, durable changes in the density of energetic particles that were first detected on Aug. 25, 2012. The Voyager team generally accepts this date as the date of interstellar arrival. The charged particle and plasma changes were what would have been expected during a crossing of the heliopause.
"The team's hard work to build durable spacecraft and carefully manage the Voyager spacecraft's limited resources paid off in another first for NASA and humanity," said Suzanne Dodd, Voyager project manager, based at NASA's Jet Propulsion Laboratory, Pasadena, Calif. "We expect the fields and particles science instruments on Voyager will continue to send back data through at least 2020. We can't wait to see what the Voyager instruments show us next about deep space."
Voyager 1 and its twin, Voyager 2, were launched 16 days apart in 1977. Both spacecraft flew by Jupiter and Saturn. Voyager 2 also flew by Uranus and Neptune. Voyager 2, launched before Voyager 1, is the longest continuously operated spacecraft. It is about 9.5 billion miles (15 billion kilometers) away from our sun.
Voyager mission controllers still talk to or receive data from Voyager 1 and Voyager 2 every day, though the emitted signals are currently very dim, at about 23 watts -- the power of a refrigerator light bulb. By the time the signals get to Earth, they are a fraction of a billion-billionth of a watt. Data from Voyager 1's instruments are transmitted to Earth typically at 160 bits per second, and captured by 34- and 70-meter NASA Deep Space Network stations. Traveling at the speed of light, a signal from Voyager 1 takes about 17 hours to travel to Earth. After the data are transmitted to JPL and processed by the science teams, Voyager data are made publicly available.
"Voyager has boldly gone where no probe has gone before, marking one of the most significant technological achievements in the annals of the history of science, and adding a new chapter in human scientific dreams and endeavors," said John Grunsfeld, NASA's associate administrator for science in Washington. "Perhaps some future deep space explorers will catch up with Voyager, our first interstellar envoy, and reflect on how this intrepid spacecraft helped enable their journey."
Scientists do not know when Voyager 1 will reach the undisturbed part of interstellar space where there is no influence from our sun. They also are not certain when Voyager 2 is expected to cross into interstellar space, but they believe it is not very far behind.
JPL built and operates the twin Voyager spacecraft. The Voyagers Interstellar Mission is a part of NASA's Heliophysics System Observatory, sponsored by the Heliophysics Division of NASA's Science Mission Directorate in Washington. NASA's Deep Space Network, managed by JPL, is an international network of antennas that supports interplanetary spacecraft missions and radio and radar astronomy observations for the exploration of the solar system and the universe. The network also supports selected Earth-orbiting missions.
The cost of the Voyager 1 and Voyager 2 missions -- including launch, mission operations and the spacecraft's nuclear batteries, which were provided by the Department of Energy -- is about $988 million through September.
For an image of the radio signal from Voyager 1 on Feb. 21 by the National Radio Astronomy Observatory's Very Long Baseline Array, which links telescopes from Hawaii to St. Croix, visit: http://www.nrao.edu .
The Space Between: This artist's concept shows the Voyager 1 spacecraft entering the space between stars. Interstellar space is dominated by plasma, ionized gas (illustrated here as brownish haze), that was thrown off by giant stars millions of years ago. Image credit: NASA/JPL-Caltech