Atlanta, GA, United States
Atlanta, GA, United States

Time filter

Source Type

News Article | May 11, 2017
Site: www.sciencenews.org

An elephant may be hundreds of times larger than a cat, but when it comes to pooping, it doesn’t take the elephant hundreds of times longer to heed nature’s call. In fact, both animals will probably get the job done in less than 30 seconds, a new study finds. Humans would probably fit in that time frame too, says Patricia Yang, a mechanical engineering graduate student at the Georgia Institute of Technology in Atlanta. That’s because elephants, cats and people all excrete cylindrical poop. The size of all those animals varies, but so does the thickness of the mucus lining in each animal’s large intestine, so no matter the mammal, everything takes about the same time — an average of 12 seconds — to come out, Yang and her colleagues conclude April 25 in Soft Matter. But the average poop time is not the real takeaway here (though it will make a fabulous answer to a question on Jeopardy one day). Previous studies on defecation have largely come from the world of medical research. “We roughly know how it happened, but not the physics of it,” says Yang. Looking more closely at those physical properties could prove useful in a number of ways. For example, rats are often good models for humans in disease research, but they aren’t when it comes to pooping because rats are pellet poopers. (They’re not good models for human urination, either, because their pee comes out differently than ours, in high-speed droplets instead of a stream.) Also, since the thickness of the mucus lining is dependent on animal size, it would be better to find a more human-sized stand-in. Such work could help researchers find new treatments for constipation and diarrhea, in which the mucus lining plays a key role, the researchers note. Animal defecation may seem like an odd topic for a mechanical engineer to take on, but Yang notes that the principles of fluid dynamics apply inside the body and out. Her previous research includes a study on animal urination, finding that, as with pooping, the time it takes for mammals to pee also falls within a small window. (The research won her group an Ig Nobel Prize in 2015.) And while many would find this kind of research disgusting, Yang does not. “Working with poop is not that bad, to be honest,” she says. “It’s not that smelly.” Plus, she gets to go to the zoo and aquarium for her research rather than be stuck in the lab. But the research does involve a lot of poop — and watching it fall. For the study, the researchers timed the how long it took for animals to defecate and calculated the velocity of the feces of 11 species. They filmed dogs at a park and elephants, giant pandas and warthogs at Zoo Atlanta. They also dug up 19 YouTube videos of mammals defecating. Surprisingly, there are a lot of those videos available, though not many were actually good for the research. “We wanted a complete event, from beginning to end,” Yang notes. Apparently not everyone interested in pooping animals bothers to capture a feces’ full fall. The researchers also examined feces from dozens of mammal species. (They fall into two classes: Carnivores defecate “sinkers,” since their feces are full of heavy indigestible ingredients like fur and bones. Herbivores defecate less-dense “floaters.”) And they considered the thickness and viscosity of the mucus that lines mammals’ intestines and helps everything move along as well the rectal pressure that pushes the material. All this information went into a mathematical model of mammal defecation — which revealed the importance of the mucus lining. Yang isn’t done with this line of research. The model she and her colleagues created applies only to mammals that poop like we do. There’s still the pellet poopers, like rats and rabbits, and wombats, whose feces look like rounded cubes. “I would like to complete the whole set,” she says. And, “if you’ve got a good team, it’s fun.”


News Article | May 25, 2017
Site: www.npr.org

Scientists Pinpoint How A Flamingo Balances On One Leg Most anyone who has encountered a flamingo has probably been impressed by its signature ability to balance on a single long, spindly leg for remarkably long periods of time. But actually, scientists have now shown that what appears to be a feat requires almost no muscle activity from the bird. In fact, they found even a dead flamingo's body will naturally fall into a stable one-leg balance if positioned vertically. That research was recently published in Biology Letters. Until now there have been two basic schools of thought about why a flamingo stands on one leg, Lena Ting, a biomedical engineer at Emory University and Georgia Institute of Technology, tells The Two-Way. Some scientists have suggested it was a way for the bird to conserve heat that would have been lost if that foot had been in the cold water. Others thought it was a way to reduce muscle fatigue, letting one leg rest while the other did the work. But for muscles to get fatigued, the posture must actually be tiring for the bird. Nobody had ever tested whether the flamingo's iconic one-legged posture required any actual muscle effort — until now. Ting and co-author Young-Hui Chang from the Georgia Institute of Technology headed to Zoo Atlanta, where they tested eight juvenile Chilean flamingos using a device called a force plate. She compares the machine to a Wii balance board or a high-tech bathroom scale – it "can measure the small motions of the body when you stand." They recorded a small amount of swaying motion when the animals were awake. But then something surprising happened – when an animal dozed off, the swaying dropped off dramatically. "And that's the opposite of what we would expect for you or me — if I was standing on one leg and then closed my eyes, typically I would see a great increase in the amount of body sway and usually that results in people having to put their foot down," she says. It suggests that while awake and active, the bird's swaying could be correcting for other movements, ultimately settling into a position while asleep that requires little to no muscle activity. That was put to the test in an experiment with a flamingo cadaver, which of course has no muscle activity because it is not living. First, the researchers tried manipulating the cadaver's joint in search of a locking mechanism that could explain the stability, she says. But the joint moved very loosely and did not lock. The key moment happened when they rotated the bird into a standing position: "We held onto its ankle ... and we turned it vertically, and then all of a sudden it just collapsed right into the position that you see when they're standing on one leg." This video shows the remarkable stability of the cadaver, even when it is pushed and pulled in different directions. (A warning to the sensitive viewer: It is a video of a dead flamingo, though the scientists say the animal was euthanized for other reasons and was not harmed for the study.) This suggests that the reason for the animal's stability is mechanical and is actually aided by gravity. "What we showed is that when they go to sleep their bodies can sort of flap forward due to gravity, and then the whole thing just collapses and becomes very stable," Ting says. The mechanics behind a flamingo's leg are a bit counterintuitive. The flamingo actually has an upper leg bone that is positioned horizontally, hidden among its feathers. A knee connects that bone to the long, slender part that it stands on. And the knobby bit in the center of that vertical portion is actually the bird's ankle. When the flamingo lifts its leg, its body folds forward, so the center of gravity is pushing down on the leg from the front of the body — perfectly balancing it. In fact, says Ting, "our research also suggests that it may require less effort for the flamingos to stand on one leg than on two." The bird was not able to maintain this kind of passive balancing on two legs; as Ting explained, when the leg unfolded the joint "sort of collapsed" from its more stable position balanced on one leg. This study is not inconsistent with the idea that flamingos stand on one leg to reduce heat loss, especially if the bird doesn't need to expend much energy to do so. But Ting says it may be even simpler than that: They may just balance on one leg because it's easier for them than any other way. It's worth noting that lots of other birds balance on one leg too, such as wood ducks and storks. Ting says this could be a "more general mechanism that many birds use."


News Article | May 26, 2017
Site: news.yahoo.com

A question flamingo researchers get asked all the time — why the birds stand on one leg — may need rethinking. The bigger puzzle may be why flamingos bother standing on two. Balance aids built into the birds’ basic anatomy allow for a one-legged stance that demands little muscular effort, tests find. This stance is so exquisitely stable that a bird sways less to keep itself upright when it appears to be dozing than when it’s alert with eyes open, two Atlanta neuromechanists report May 24 in Biology Letters. “Most of us aren’t aware that we’re moving around all the time,” says Lena Ting of Emory University, who measures what’s called postural sway in standing people as well as in animals. Just keeping the human body vertical demands constant sensing and muscular correction for wavering.  Even standing robots “are expending quite a bit of energy,” she says. That could have been the case for flamingos, she points out, since effort isn’t always visible. Translate that improbably long flamingo leg into human terms, and the visible part of the leg would be just the shin down. A flamingo’s hip and knee lie inside the bird’s body. Ting and Young-Hui Chang of the Georgia Institute of Technology tested balance in fluffy young Chilean flamingos coaxed onto a platform attached to an instrument that measures how much they sway. Keepers at Zoo Atlanta hand-rearing the test subjects let researchers visit after feeding time in hopes of catching youngsters inclined toward a nap — on one leg on a machine. “Patience,” Ting says, was the key to any success in this experiment. As a flamingo standing on one foot  shifted to preen a feather or joust with a neighbor, the instrument tracked wobbles in the foot’s center of pressure, the spot where the bird’s weight focused. When a bird tucked its head onto its pillowy back and shut its eyes, the center of pressure made smaller adjustments (within a radius of 3.2 millimeters on average, compared with 5.1 millimeters when active). Museum bones revealed features of the skeleton that might enhance stability, but bones alone didn’t tell the researchers enough. Deceased Caribbean flamingos a zoo donated to science gave a better view. “The ‘ah-ha!’ moment was when I said, ‘Wait, let’s look at it in a vertical position,’” Ting remembers. All of a sudden, the bird specimen settled naturally into one-legged lollipop alignment. In flamingo anatomy, the hip and the knee lie well up inside the body. What bends in the middle of the long flamingo leg is not a knee but an ankle (which explains why to human eyes a walking flamingo’s leg joint bends the wrong way). The bones themselves don’t seem to have a strict on-off locking mechanism, though Ting has observed bony crests, double sockets and other features that could facilitate stable standing. The bird’s distribution of weight, however, looked important for one-footed balance. The flamingo’s center of gravity was close to the inner knee where bones started to form the long column to the ground, giving the precarious-looking position remarkable stability. The specimen’s body wasn’t as stable on two legs, the researchers found. A young flamingo hand-reared at Zoo Atlanta settles onto one foot on an instrument for tracking waverings in posture. Measurements of one bird show the smallest shifts (red squiggles, right) of the center of pressure on its foot (in rectangles), where its weight is focused when the bird is quiescent, possibly dozing. When active, preening a feather or leaning to cackle at another youngster, the bird shows the biggest shifts.


News Article | May 24, 2017
Site: www.sciencenews.org

A question flamingo researchers get asked all the time — why the birds stand on one leg — may need rethinking. The bigger puzzle may be why flamingos bother standing on two. Balance aids built into the birds’ basic anatomy allow for a one-legged stance that demands little muscular effort, tests find. This stance is so exquisitely stable that a bird sways less to keep itself upright when it appears to be dozing than when it’s alert with eyes open, two Atlanta neuromechanists report May 24 in Biology Letters. “Most of us aren’t aware that we’re moving around all the time,” says Lena Ting of Emory University, who measures what’s called postural sway in standing people as well as in animals. Just keeping the human body vertical demands constant sensing and muscular correction for wavering.  Even standing robots “are expending quite a bit of energy,” she says. That could have been the case for flamingos, she points out, since effort isn’t always visible. Ting and Young-Hui Chang of the Georgia Institute of Technology tested balance in fluffy young Chilean flamingos coaxed onto a platform attached to an instrument that measures how much they sway. Keepers at Zoo Atlanta hand-rearing the test subjects let researchers visit after feeding time in hopes of catching youngsters inclined toward a nap — on one leg on a machine. “Patience,” Ting says, was the key to any success in this experiment. As a flamingo standing on one foot  shifted to preen a feather or joust with a neighbor, the instrument tracked wobbles in the foot’s center of pressure, the spot where the bird’s weight focused. When a bird tucked its head onto its pillowy back and shut its eyes, the center of pressure made smaller adjustments (within a radius of 3.2 millimeters on average, compared with 5.1 millimeters when active). Museum bones revealed features of the skeleton that might enhance stability, but bones alone didn’t tell the researchers enough. Deceased Caribbean flamingos a zoo donated to science gave a better view. “The ‘ah-ha!’ moment was when I said, ‘Wait, let’s look at it in a vertical position,’” Ting remembers. All of a sudden, the bird specimen settled naturally into one-legged lollipop alignment. In flamingo anatomy, the hip and the knee lie well up inside the body. What bends in the middle of the long flamingo leg is not a knee but an ankle (which explains why to human eyes a walking flamingo’s leg joint bends the wrong way). The bones themselves don’t seem to have a strict on-off locking mechanism, though Ting has observed bony crests, double sockets and other features that could facilitate stable standing. The bird’s distribution of weight, however, looked important for one-footed balance. The flamingo’s center of gravity was close to the inner knee where bones started to form the long column to the ground, giving the precarious-looking position remarkable stability. The specimen’s body wasn’t as stable on two legs, the researchers found. Reinhold Necker of Ruhr University in Bochum, Germany, is cautious about calling one-legged stances an energy saver. “The authors do not consider the retracted leg,” says Necker, who has studied flamingos. Keeping that leg retracted could take some energy, even if easy balancing saves some, he proposes. The new study takes an important step toward understanding how flamingos stand on one leg, but doesn’t explain why, comments Matthew Anderson, a comparative psychologist at St. Joseph’s University in Philadelphia. He’s found that more flamingos rest one-legged when temperatures drop, so he proposes that keeping warm might have something to do with it. The persistent flamingo question still stands.


News Article | May 24, 2017
Site: phys.org

Of course, as humans, we think standing on one leg is hard because it's difficult for us. Tree pose in yoga becomes increasingly difficult as you lift your leg higher, reach your arms up and tilt your head. It becomes almost impossible if you close your eyes. Most of us wobble and sway, then put a foot down, and shake out the leg we were standing on. As scientists, the two of us are interested in how the brain controls the body – a field we call neuromechanics, at the intersection of biomechanics and neuroscience. Our latest research question: Just how do flamingos stand on one leg? Our search brought us up close and personal with a flock of juvenile flamingos and even flamingo skeletons and cadavers to figure out how they achieve their amazing feats of balance. When we searched the literature, we didn't find any reports on how these iconic birds do it, but there were several theories about why they stand on one leg. Some people thought it was to conserve body heat lost by standing in cold water. Standing on one leg would presumably cut the energy lost to heat in half. Another hypothesis is that standing on one leg reduces muscle fatigue by giving one leg a rest while the other supports the body. This theory is based on the idea that standing on two legs is more fatiguing than standing alternately on one leg and then the other, but no one has ever directly tested that. A large proportion of the metabolic energy any animal expends is due to activating muscles as they stand up against gravity and control movement. If there were an added energetic cost for standing on one leg, it would not make much sense for flamingos to save on thermal energy loss only to lose on muscular energy expenditure. And if it was fatiguing for flamingos to stand on one leg, why would they switch between one leg and the other instead of standing on two legs? When you stand in line at the grocery store, you don't stand with your knees bent – that would require you to expend a huge amount of energy to activate your leg muscles. Imagine holding a squat posture with your thigh horizontal and your knee at a right angle – you'd quickly feel the burn. Flamingo legs (like other birds) are constantly in a state of "bent knees," so there is the potential for large muscular energy expenditure, or muscular effort, necessary to support their body weight. Many animals have evolved ways of moving that minimize the amount of energy they expend, whether it's the pendular mechanics of penguins waddling and gibbons swinging through the trees or the bouncing mechanics of cockroaches. Other animals, such as horses, have evolved passive stabilizing mechanisms to allow them to sleep while standing. Hanging bats and perching birds have evolved passive mechanisms for grasping that allow them to sleep without fear of losing their grip. We set out to find whether flamingos relied mostly on passive biomechanics or active nervous system interventions to stand on one leg. One way scientists study balance is to have people or animals stand on a device called a force plate that measures the forces they apply to the ground. It works like a fancy Wii Balance Board. From these measurements, we can compute "postural sway" – the constant motion of the body when standing on one, two or even four limbs. We don't see postural sway in structures that are mechanically stable, like a table. Although standing balance is something we as humans take for granted, it is actually a very active process. The nervous system constantly senses the motion of the body as it stands and makes corrections by activating muscles. The amount of postural sway is an indirect indicator of that nervous system activity. We typically don't notice these small movements unless something is wrong with our balance. Think about closing your eyes on a moving surface, or standing when you're dizzy. In our measurements, we found that juvenile flamingos from Zoo Atlanta had remarkably little postural sway as they were falling asleep while standing on one leg. When they were awake, and grooming or jousting with their buddies, while standing on one leg, their speed of the postural sway increased up to seven times. How was this happening? We turned to anatomical reports and skeletons of flamingos to see if we could find evidence of biomechanical stabilizing mechanisms that help flamingos easily stand on one leg. Finding no clear demonstrations, we decided that we needed to do our own study of flamingo morphology – that is, the bird's structural features, and how they function together. While the actual mechanism is still unclear, we made an unanticipated discovery from a flamingo cadaver. If you hold it up by one leg like a lollipop at just the right angle, it passively adopts a body configuration that looks like a flamingo standing on one leg. When we tilted the body forward and backward by up to 45 degrees, the body configuration was stable, with the knee keeping a right angle. When we tried to manipulate the body, we found that the joints were quite stable in resisting the pull of gravity, but that the joints could be easily moved in the other direction. Gravity plus anatomy do the job Our findings show that gravity, along with specializations in flamingo anatomy, plays an important role in helping the animals stay stable on one leg without locking their joints, which may allow them to escape rapidly if necessary. The angle of the cadaver leg when viewed from the front resembled the inward tilt we observe when the live animals are standing on one leg. When the leg was angled inward (viewed from the front) like a one-legged pose, the joints became very stable. If we held the cadaver leg more upright – that is, more vertical when viewed from the front, resembling the posture when flamingos stand on two legs – the body was no longer stable. Since muscles aren't active in a deceased animal, we interpreted this to mean that muscles must be activated for a flamingo to maintain a two-legged, but not a one-legged, posture. Before our investigation, we might have assumed that it required a lot of muscle energy for a flamingo to stand on one leg. But apparently it doesn't. They can easily and for long periods hold what for us would quickly become a very uncomfortable squat pose – without using their muscles much at all. Why do we care? This study was a fun inquiry that revealed how different standing on one leg is for a flamingo compared to a person. As scientists, it's rewarding to study the wonders of nature and to see how physics and biology are intertwined in the behavior of animals. Still, there are practical lessons that can be learned. Engineered systems with motorized joints and legs, such as some prosthetic devices and humanoid robots, expend quite a lot of energy just to stand up. Perhaps using some principles of flamingo balance could help to design more stable, yet agile and efficient, prostheses and robots. Explore further: Babies learning to stand more stable when holding object, study finds More information: Young-Hui Chang et al. Mechanical evidence that flamingos can support their body on one leg with little active muscular force, Biology Letters (2017). DOI: 10.1098/rsbl.2016.0948


News Article | April 26, 2017
Site: phys.org

"Frogs of the World" represents the first-ever use of 3D technology to preserve accurate, high-resolution models of some of the most endangered frog species on the planet, say Irschick and members of the interdisciplinary Digital Life team. Many of the 3D models released today were created with a new photogrammetry rig created by UMass Amherst undergraduate Trevor Mayhan called the "Beastcam MACRO," customized for small live animals. It is part of the broader Beastcam technology platform designed for rapidly capturing high-resolution, full-color 3D models of living organisms, Irschick explains. The Digital Life team is using this technology to create accurate, high-resolution models of all life on earth. Tatjana Dzambazova of the 3D design and software firm Autodesk, Inc. and a member of the Digital Life advisory committee, says the 3D models already captured - of frogs, sharks, scorpions, toads, lizards, flowers and invertebrates—can be useful as educational tools in virtual reality or in other computer software, and can be 3D printed to educate children about animal diversity. Also, models can benefit scientists because they represent true-to-life digital replicas of live organisms, enabling a range of new scientific inquiries. "Imagine a comprehensive, true-to-life 3D library of all the existing species in the world available online to anyone. With technology developed by Digital Life and accessible tools such as Autodesk ReMake, technology today can help us understand and appreciate the natural world around us in a new way," she adds. Digital Life's new online 3D frog images include some of the rarest frogs on earth, such as the Panamanian golden frog, Atelopus zeteki, as well as more common species such as the horned frog Ceratophrys. They were scanned in the field in the Philippines by researchers from the University of Oklahoma, as well as at Zoo Atlanta, the Amphibian Foundation and at UMass Amherst. Their photogrammetric process integrates 2D digital photos into 3D models using software such as ReMake. Digital Life director Irschick explains that he and his team hope that making 3D models of living animals will promote conservation, science and research, and public awareness, not only for endangered species but for more common ones that are crucial to ecosystems around the world. "In a race against time, I believe that Digital Life has taken a large step forward in preserving the heritage of these frogs," says photographer Christine Shepard, a member of the Digital Life team. Mark Mandica, executive director of the Amphibian Foundation, a partner on the Frogs of the World project, says the models will provide needed support for the worldwide effort to conserve frog species. The amphibians represent a good test case for the Digital Life's project, he adds. "Aside from frogs facing global population declines, they represent some of the greatest biodiversity the earth has to offer. Frogs are virtually limitless in color and pattern variation, as well as shapes and sizes," he notes. Joseph Mendelson, director of research at Zoo Atlanta, points out that approximately 38 percent of all amphibians face significant threats from development, climate change or the chytrid fungus. Cameron Siler at the University of Oklahoma adds, "In addition to their conservation value, these models show the promise of using 3D technology to digitally preserve specimens for biodiversity and museum-based research." Explore further: New 'digital life' initiative aims to create 3-D models of all living creatures


News Article | April 27, 2017
Site: phys.org

Sure, it's uncomfortable to talk about. But that's where science comes in, because what we don't like to discuss can still cause harm. Irritable bowel syndrome, inflammatory bowel disease, gastrointestinal infections and other poop-related ailments cost Americans billions of dollars annually. But trying to stem these problems was not our main motivation for trying to figure out some of the physics of defecation. It was something else, much more sinister. From personal observation, into the lab When parenthood hits, it hits hard. One of us is a working dad who survived by learning a new set of skills, one of which was fecal analysis. Years of diaper changes and then potty training turned me from a poo-analysis novice to a wizened connoisseur. My life passes by in a series of images: hard feces pellets like peas to long feces like a smooth snake to a puddle of brown water. Unlike the ancients, we didn't believe that we could predict the future from children's stool. But we did think it was worth trying to understand where all these shapes come from. Having a laboratory to answer questions about the everyday world is one of the distinct pleasures of being a scientist. As fluid dynamicists, we joined forces with colorectal surgeon Daniel Chu, and two stalwart undergraduates, Candice Kaminski and Morgan LaMarca, who filmed defecation and hand-picked feces from 34 mammalian species at Zoo Atlanta in order to measure their density and viscosity. We learned that most elephants and other herbivores create "floaters" while most tigers and other carnivores create "sinkers." Inadvertently, we also ranked feces from most to least smelly, starting with tiger and rhino and going all the way to panda. The zoo's variety of animals provided us with a range of fecal sizes and shapes that served as independent pieces of evidence to validate our mathematical model of the duration of defecation. We also placed the feces in a device called a "rheometer," a precision blender that can measure the properties of liquid-like and solid-like materials such as chocolate and shampoo. Our lab shares two rheometers with Georgia Tech physicist Alberto Fernandez-Nieves. We have since categorized the rheometers as the "clean rheometer" and the "David Hu rheometer" – which has seen its fair share of frog saliva, mucus and feces. The secret to the speed What else did we learn? Bigger animals have longer feces. And bigger animals also defecate at higher speed. For instance, an elephant defecates at a speed of six centimeters per second, nearly six times as fast as a dog. The speed of defecation for humans is in between: two centimeters per second. Together, this meant that defecation duration is constant across many animal species – around 12 seconds (plus or minus 7 seconds) – even though the volume varies greatly. Assuming a bell curve distribution, 66 percent of animals take between 5 and 19 seconds to defecate. It's a surprisingly small range, given that elephant feces have a volume of 20 liters, nearly a thousand times more than a dog's, at 10 milliliters. How can big animals defecate at such high speed? The answer, we found, was in the properties of an ultra-thin layer of mucus lining the walls of the large intestine. The mucus layer is as thin as human hair, so thin that we could measure it only by weighing feces as the mucus evaporated. Despite being thin, the mucus is very slippery, more than 100 times less viscous than feces. During defecation, feces moves like a solid plug. Therefore, in ideal conditions, the combined length and diameter of feces is simply determined by the shape of one's rectum and large intestine. One of the big findings of our study was that feces extend halfway up the length of the colon from the rectum. Putting the length of feces together with the properties of mucus, we now have a cohesive physics story for how defecation happens. Bigger animals have longer feces, but also thicker mucus, enabling them to achieve high speeds with the same pressure. Without this mucus layer, defecation might not be possible. Alterations in mucus can contribute to several ailments, including chronic constipation and even infections by bacteria such as C. difficile in the gastrointestinal tract. Beyond simply following our scientific curiosity, our measurements of feces have also had some practical applications. Our defecation data helped us design an adult diaper for astronauts. Astronauts want to stay in space suits for seven days, but are limited by their diapers. Taking advantage of the viscosity of feces, we designed a diaper that segregates the feces away from direct contact with skin. It was a semifinalist in the NASA Space Poop Challenge earlier this year. It just shows that physics and mathematics can be used everywhere, even in your toilet bowl. More information: Patricia J Yang et al. Hydrodynamics of defecation, Soft Matter (2017). DOI: 10.1039/C6SM02795D


News Article | April 19, 2017
Site: www.sciencemag.org

Europe's largest and best known salamander species, the fire salamander, is falling victim to a deadly fungus, and new research is making scientists more pessimistic about its future. A 2-year study of a population in Belgium, now entirely wiped out, has revealed that these amphibians can't develop immunity to the fungus, as was hoped. To make matters worse, it turns out the fungus creates a hardy spore that can survive in water for months and also stick to birds' feet, offering a way for it to spread rapidly across the continent. Two other kinds of amphibians, both resistant to the disease, also act as carriers for the highly infectious spores. "This is terrible news," says geneticist Matthew Fisher of Imperial College London, who studies the fungus but was not involved in the new research. "This isn't a problem that's going to go away. It's a problem that's going to get worse." The pathogen, Batrachochytrium salamandrivorans (Bsal), is a chytrid fungus, a type that lives in damp or wet environments and typically consumes dead organic matter. Bsal infects and eats the skin of salamanders, causing lesions, apathy, loss of appetite, and eventually death. Over the past few decades, a related fungus, B. dendrobatidis (Bd), has struck hard at amphibian populations around the world, particularly in the Americas, Australia, Spain, and Portugal. More than 200 species of frogs and toads are thought to have gone extinct, including many kinds of Costa Rica's striking stream-breeding toads. Bsal was identified in a nature reserve in the Netherlands in 2013 after fire salamanders started dying with ulcers and sores similar to those caused by Bd. Fire salamanders (Salamandra salamandra) grow up to 35 centimeters long, can live more than 40 years, and hunt insects and other small prey in forest streams. Their bright yellow spots warn predators of poison around their head and back. In the Dutch nature reserve, the population plummeted 99.9%. The fungus is thought to have arrived in Europe via salamanders or newts imported from Asia for the pet trade. Bsal has since been found in Belgium and Germany in both fire salamanders and alpine newts. As soon as Bsal was spotted in Belgium in April 2014, veterinarian An Martel of Ghent University in Merelbeke, Belgium, and her colleagues began visiting every month to track the population. About 90% of the fire salamanders died within 6 months, and after 2 years all were gone. The fieldwork revealed that adult animals were more likely to get infected, which makes sense because they are in closer contact with each other—through fighting for mating and breeding, for example—than are juveniles. But the death of these adults means that the population likely won't recover. There was no immune response detected in any of the sick animals in the lab, suggesting that it will be impossible to develop a vaccine, the team reports today in . "We really wanted to find solutions to mitigate disease, to save the salamanders, but everything turned out bad," Martel says. The team had also hoped that the fungus would become less virulent—as often occurs when a pathogen reaches a new host that lacks any immunity—but that hasn't happened: Fungal spores taken from the last fire salamanders in the Belgian forest, when dripped onto the backs of healthy salamanders in the lab, were just as lethal as those collected early in the outbreak. "When they come in contact with a single spore, they will die." The paper has more bad news. Researchers knew that Bsal makes spores with a tiny tail called a flagellum, which propels them toward amphibians. If spores dry out, they die. Otherwise, they typically survive for a few days before being eaten by protozoa. But Martel's group discovered that Bsal makes a second type of spore that looks much hardier and is rarely eaten by protozoa. "This will make it almost impossible to eradicate the fungus from the environment," says Martel, who adds that the spores can survive in pond water for more than 2 months. Another experiment showed that soil remained infectious for 48 hours after it was walked on by a sick salamander. In a separate lab test, the spores adhered to goose feet, suggesting they could hitchhike long distances on birds. The group also showed that two species that share the same habitat as the fire salamander are likely carriers of the disease. Midwife toads (Alytes obstetricans) could be infected with the fungus and shed spores for a few weeks, but they didn't get sick. A high dose of the fungus killed alpine newts (Ichthyosaura alpestris), but low doses made them infectious for months without killing them. As has happened with Bd in the Americas, Bsal will lurk in these reservoirs of disease even after local populations of fire salamanders vanish. Any fire salamanders that arrive from elsewhere will likely get infected by newts or toads. According to results from previous infection trials, most salamander species in Europe are likely just as vulnerable to Bsal. The fire salamander has a range that extends across Europe, and the fear is that the fungus will reach endangered salamanders. With small populations, these species could more easily be driven extinct, Fisher says. "The assumption is that they are all at risk," he says, and the findings in the new paper "have really upped their risk status." Martel and European colleagues recently started monitoring for Bsal in seven countries. It is possible to cure amphibians in the lab. For animals that can take the heat, like fire salamanders, 10 days at 25°C will kill the fungus. Other species can be cured with a combination of two drugs. But there is no practical solution for animals in the wild, especially when their habitat is contaminated with fungal spores. Herpetologist Jaime Bosch of the National Museum of Natural History in Madrid had a rare success in eliminating a chytrid fungus from the wild. A few years ago, he and colleagues got rid of Bd on the Spanish island of Mallorca by temporarily removing some 2000 tadpoles of the Mallorcan midwife toad (Alytes muletensis) and disinfecting their ponds with powerful chemicals. But this success would be hard to replicate in less isolated locations, he says. "Right now, we are very far away from having any solution." The only hope in the meantime, Bosch and others say, is to slow the spread of the disease by ending the importation of amphibians. The United States, a hot spot of amphibian diversity, has already taken steps in that direction. Last year, the U.S. Fish and Wildlife Service banned the import of 201 species of salamanders on the grounds that they might introduce the fungus. Joe Mendelson, a herpetologist at Zoo Atlanta, says the new research suggests the list should be expanded to include other carriers such as the toad and newt studied in the new paper. "This is a very important piece of work, and it's terrifying," he says. "If Bsal gets loose in the United States," he says, "it's going to be bad."


News Article | April 29, 2017
Site: motherboard.vice.com

The ancient Chinese practiced copromancy, the diagnosis of health based on the shape, size and texture of feces. So did the Egyptians, the Greeks and nearly every ancient culture. Even today, your doctor may ask when you last had a bowel movement and to describe it in exquisite detail. Sure, it's uncomfortable to talk about. But that's where science comes in, because what we don't like to discuss can still cause harm. Irritable bowel syndrome, inflammatory bowel disease, gastrointestinal infections and other poop-related ailments cost Americans billions of dollars annually. But trying to stem these problems was not our main motivation for trying to figure out some of the physics of defecation. It was something else, much more sinister. From personal observation, into the lab When parenthood hits, it hits hard. One of us is a working dad who survived by learning a new set of skills, one of which was fecal analysis. Years of diaper changes and then potty training turned me from a poo-analysis novice to a wizened connoisseur. My life passes by in a series of images: hard feces pellets like peas to long feces like a smooth snake to a puddle of brown water. Unlike the ancients, we didn't believe that we could predict the future from children's stool. But we did think it was worth trying to understand where all these shapes come from. Having a laboratory to answer questions about the everyday world is one of the distinct pleasures of being a scientist. As fluid dynamicists, we joined forces with colorectal surgeon Daniel Chu, and two stalwart undergraduates, Candice Kaminski and Morgan LaMarca, who filmed defecation and hand-picked feces from 34 mammalian species at Zoo Atlanta in order to measure their density and viscosity. Raw footage of an elephant at the Atlanta Zoo. We learned that most elephants and other herbivores create "floaters" while most tigers and other carnivores create "sinkers." Inadvertently, we also ranked feces from most to least smelly, starting with tiger and rhino and going all the way to panda. The zoo's variety of animals provided us with a range of fecal sizes and shapes that served as independent pieces of evidence to validate our mathematical model of the duration of defecation. We also placed the feces in a device called a "rheometer," a precision blender that can measure the properties of liquid-like and solid-like materials such as chocolate and shampoo. Our lab shares two rheometers with Georgia Tech physicist Alberto Fernandez-Nieves. We have since categorized the rheometers as the "clean rheometer" and the "David Hu rheometer," which has seen its fair share of frog saliva, mucus, and feces. The secret to the speed What else did we learn? Bigger animals have longer feces. And bigger animals also defecate at higher speed. For instance, an elephant defecates at a speed of six centimeters per second, nearly six times as fast as a dog. The speed of defecation for humans is in between: two centimeters per second. Together, this meant that defecation duration is constant across many animal species – around 12 seconds (plus or minus 7 seconds) – even though the volume varies greatly. Assuming a bell curve distribution, 66 percent of animals take between 5 and 19 seconds to defecate. It's a surprisingly small range, given that elephant feces have a volume of 20 liters, nearly a thousand times more than a dog's, at 10 milliliters. How can big animals defecate at such high speed? The answer, we found, was in the properties of an ultra-thin layer of mucus lining the walls of the large intestine. The mucus layer is as thin as human hair, so thin that we could measure it only by weighing feces as the mucus evaporated. Despite being thin, the mucus is very slippery, more than 100 times less viscous than feces. During defecation, feces moves like a solid plug. Therefore, in ideal conditions, the combined length and diameter of feces is simply determined by the shape of one's rectum and large intestine. One of the big findings of our study was that feces extend halfway up the length of the colon from the rectum. Putting the length of feces together with the properties of mucus, we now have a cohesive physics story for how defecation happens. Bigger animals have longer feces, but also thicker mucus, enabling them to achieve high speeds with the same pressure. Without this mucus layer, defecation might not be possible. Alterations in mucus can contribute to several ailments, including chronic constipation and even infections by bacteria such as C. difficile in the gastrointestinal tract. Beyond simply following our scientific curiosity, our measurements of feces have also had some practical applications. Our defecation data helped us design an adult diaper for astronauts. Astronauts want to stay in space suits for seven days, but are limited by their diapers. Taking advantage of the viscosity of feces, we designed a diaper that segregates the feces away from direct contact with skin. It was a semifinalist in the NASA Space Poop Challenge earlier this year. It just shows that physics and mathematics can be used everywhere, even in your toilet bowl. This post was originally published on The Conversation.


News Article | February 15, 2017
Site: www.cnet.com

In an expert example of how to lose a Super Bowl bet, Georgia's Zoo Atlanta trolled New England Patriots fans, and gave the rest of us a good laugh. The zoo had a bet on the big game with Roger Williams Park Zoo in Providence, Rhode Island. Whichever zoo's team lost would have to name a baby animal after the opposing team's quarterback and post a video about it. And not just any baby animal, but a Madagascar hissing cockroach -- no matter which side lost. The zoo introduced little-bitty Brady in an Instagram video posted Monday. Best of all, tiny little Brady is joining a family that shares his name -- the zoo has dubbed the other roaches Mike, Carol, Greg, Marcia, Peter, Jan. Cindy and Bobby. (Even though her last name wasn't Brady, we kind of want an Alice, too.) He's so small, about five of him would fit on an adult thumbnail, so he wouldn't fare well against a defensive end like Atlanta's Dwight Freeney. Not everyone loved the idea. "Yea not funny really," Instagram user lfenske wrote of the zoo's video. "Kinda petty." But user noml_noml saw the positive side, considering roaches' reputation for indestructibility. "Fitting Brady would still be playing after the bomb drops. #invincible" It's Complicated: This is dating in the age of apps. Having fun yet? These stories get to the heart of the matter. Batteries Not Included: The CNET team reminds us why tech is cool.

Loading Zoo Atlanta collaborators
Loading Zoo Atlanta collaborators