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How climate change will hurt humanity’s closest cousins

The consequences of climate change are an increasing concern for humans around the world. How will we cope with rising sea levels and climbing temperatures? But it’s not just humans who will be affected by these worldwide shifts — it’s our closest cousins, too: monkeys, apes and lemurs.

A new Concordia study published in the International Journal of Primatology shows that the world’s primate populations may be seriously impacted by climate change.

“Our research shows that climate change may be one of the biggest emerging threats to primates, compounding existing pressures from deforestation, hunting and the exotic pet trade,” says Tanya Graham, the article’s lead author and an MSc student in the Department of Geography, Planning and Environment.

She worked with environment professor Damon Matthews from Concordia and primatology post-doctoral researcher Sarah Turner from McGill to assess the exposure and potential vulnerability of all non-human primate species to projected future temperature and precipitation changes. They found that overall, 419 species of non-human primates — such as various species of lemurs, lorises, tarsiers, monkeys and apes — will experience 10 per cent more warming than the global average, with some primate species experiencing increases of more than 1.5 degrees Celsius in annual average temperature for every degree of global warming.

The researchers also identified several hotspots of primate vulnerability to climate change, based on the combination of the number of species, their endangered status and the severity of climate changes at each location. Overall, the most extreme hotspots, which represent the upper 10 per cent of all hotspot scores, cover a total area of 3,622,012 square kilometres over the ranges of 67 primate species.

The highest hotspot scores occur in Central America, the Amazon and southeastern Brazil, as well as portions of East and Southeast Asia — prime territory for some of the globe’s best-known primates who call these areas home.

The ursine howler monkey, black howler monkey, and barbary macaque are expected to be exposed to the highest magnitude of climate change when both temperature and precipitation are considered. For example, the ursine howler monkey, found in Venezuela, will experience an increase of 1.2 degrees Celsius annually and a 5.3 per cent decline in annual rainfall for each degree of global temperature increase.

“This study highlights the vulnerability of individual species, as well as regions in which primates as a whole may be vulnerable to climate change,” says Matthews, who will present the findings of this study during the Joint Meeting of the International Primatological Society and the American Society of Primatologists in Chicago later this month.

“Our findings can be taken as priorities for ongoing conservation efforts, given that any success in decreasing other current human pressures on endangered species may also increase that species’ ability to withstand the growing pressures of climate changes,” says Graham.

“Primates are often seen as flagship species for entire ecosystems, so conservation can have important ramifications for many other species too. I hope our study will help direct conservation efforts for individual primate species in particular, but also for vulnerable ecosystems in general throughout the tropical regions inhabited by non-human primates,” adds Turner.

This study was funded in part by the Concordia Institute for Water, Energy and Sustainable Systems, the Natural Sciences and Engineering Research Council of Canada and the Fonds de recherche du Québec — Nature et technologies.

https://www.sciencedaily.com/  Science Daily

https://www.sciencedaily.com/releases/2016/08/160810114052.htm  Original web page at Science Daily

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Labrador study offers vets clues on why dogs’ tails lose their wag

A painful condition that affects dogs’ tails may be more common than previously thought, a study suggests.

The research offers clues to potential causes of the illness — known as limber tail — which mostly affects larger working dog breeds, such as Labrador Retrievers.

Researchers say their findings are the first step towards preventing the distressing condition, which causes the tail to become limp and painful.

The team at the University of Edinburgh compared 38 cases of limber tail that were identified from owners’ reports about their dogs’ health with 86 dogs that had no tail symptoms.

Their goal was to gain insight into habits and lifestyle factors that might explain why some dogs are affected and not others.

The majority of dogs in the study were pets but those affected by limber tail were more likely to be working dogs, they found.

Swimming has previously been thought to be a risk factor for limber tail, which is sometimes known as ‘swimmers’ tail’. Some but not all of the affected dogs had been swimming prior to the onset of symptoms, the study found.

Dogs with the condition were more likely to live in northern areas, lending support to anecdotal reports that limber tail is associated with exposure to the cold.

Labradors that had suffered limber tail were more likely to be related to each other than unaffected dogs, which may indicate an underlying genetic risk.

Experts hope that further studies will identify genes associated with the condition, which could one day help breeders to identify animals that are likely to be affected. Over time, this could help to reduce the disease prevalence.

The symptoms usually resolve within a few days or weeks so many cases are not reported to vets. This may be why it has been so underestimated in the past. However, owners report that it can be very painful and distressing for the animals.

The study is the first large-scale investigation of limber tail and was conducted as part of the Dogslife project, which follows the health and wellbeing of more than 6000 Labradors from across the UK.

Dr Carys Pugh, who led the study at the University’s Roslin Institute and Royal (Dick) School of Veterinary Studies, said: “We were surprised by how many owners were reporting limber tail to us but it meant we had the chance to do a detailed investigation.

“We have been able to add evidence to a lot of internet speculation about risk factors and the new findings relating to geographical region and family links give us avenues to pursue in understanding and avoiding the condition.”

The study, published in the Veterinary Record, was funded by the Kennel Club Charitable Trust. The Roslin Institute receives strategic funding from the Biotechnology and Biological Sciences Research Council.

https://www.sciencedaily.com/  Science Daily

https://www.sciencedaily.com/releases/2016/08/160801110205.htm Original web page at Science Daily

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How birds soar to great heights

Migratory birds often use warm, rising atmospheric currents to gain height with little energy expenditure when flying over long distances.

It’s a behavior known as thermal soaring that requires complex decision-making within the turbulent environment of a rising column of warm air from the sun baked surface of the earth.

But exactly how birds navigate within this ever-changing environment to optimize their thermal soaring was unknown until a team of physicists and biologists at the University of California San Diego took an exacting computational look at the problem.

In this week’s online version of the journal Proceedings of the National Academy of Sciences, the scientists demonstrated with mathematical models how glider pilots might be able to soar more efficiently by adopting the learning strategies that birds use to navigate their way through thermals.

“Relatively little is known about the navigation strategies used by birds to cope with these challenging conditions, mainly because past computational research examined soaring in unrealistically simplified situations,” explained Massimo Vergassola, a professor of physics at UC San Diego.

To tackle the problem, he and his colleagues, including Terrence Sejnowski, a professor of neurobiology at the Salk Institute and UC San Diego, combined numerical simulations of atmospheric flow with “reinforcement learning algorithms” — equations originally developed to model the behavior and improved performance of animals learning a new task. Those algorithms were developed in a manner that trained a glider to navigate complex turbulent environments based on feedback on the glider’s soaring performance.

According to Sejnowski, the “reinforcement learning architecture” was the same as that used by Google’s DeepMind AlphaGo program, which made headlines in 2016 after beating the human professional Go player Lee Sedol.

When applying it to soaring performance, the researchers took into account the bank angle and the angle of attack of the glider’s wings as well as how the temperature variations within the thermal impacted vertical velocity.

“By sensing two environmental cues — vertical wind acceleration and torque — the glider is able to climb and stay within the thermal core, where the lift is typically the largest, resulting in improved soaring performance, even in the presence of strong turbulent fluctuations,” said Vergassola. “As turbulent levels rise, the glider can avoid losing height by adopting increasingly conservative, risk-averse flight strategies, such as continuing along the same path rather than turning.”

The researchers write in their paper that, based on their study, “torque and vertical accelerations” appear to be the sensorimotor cues that most effectively guide the most efficient soaring path of birds through thermals, rather than differences in temperature.

“Temperature was specifically shown to yield minor gains,” they write adding that “a sensor of temperature could then be safely spared in the instrumentation for autonomous flying vehicles.”

“Our findings shed light on the decision-making processes that birds might use to successfully navigate thermals in turbulent environments,” said Vergassola. “This information could guide the design of simple mechanical instrumentation that would allow autonomous gliders to travel long distances with minimal energy consumption.”

“The high levels of soaring performance demonstrated in simulated turbulence could lead to the development of energy efficient autonomous gliders,” said Sejnowski, who is also a Howard Hughes Medical Institute Investigator.

Other members of the research team were Gautam Reddy, a physicist at UC San Diego and the first author of the paper, and Antonio Celani of the Abdus Salam International Center for Theoretical Physics in Trieste, Italy. The study was supported by a grant from the Simons Foundation.

https://www.sciencedaily.com/  Science Daily

https://www.sciencedaily.com/releases/2016/08/160801163844.htm  Original web page at Science Daily

 

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An hour of moderate exercise a day enough to counter health risks from prolonged sitting

The health risks associated with sitting for eight or more hours a day — whether at work, home or commuting — can be eliminated with an hour or more of physical activity a day, according to a study from an international team of researchers.

Ever since a study back in 1953 discovered that London bus drivers were at greater risk of heart disease compared to bus conductors, scientists have found increasing evidence that lack of physical activity is a major risk factor for several diseases and for risk of early death. Recent estimates suggest that more than 5 million people die globally each year as a result of failing to meet recommended daily activity levels.

Studies in high-income countries have suggested that adults spend the majority of their waking hours sitting down. A typical day for many people is driving to work, sitting in an office, driving home and watching TV. Current physical activity guidelines recommend that adults do at least 150 minutes of moderate intensity exercise per week.

In an analysis published today in The Lancet that draws together a number of existing studies, an international team of researchers asked the question: if an individual is active enough, can this reduce, or even eliminate, the increased risk of early death associated with sitting down?

In total the researchers analysed 16 studies, which included data from more than one million men and women. The team grouped individuals into four quartiles depending on their level of moderate intensity physical activity, ranging from less than 5 minutes per day in the bottom group to over 60 minutes in the top. Moderate intensity exercise was defined as equating to walking at 3.5 miles/hour or cycling at 10 miles/hour, for example.

The researchers found that 60 to 75 minutes of moderate intensity exercise per day were sufficient to eliminate the increased risk of early death associated with sitting for over eight hours per day. However, as many as three out of four people in the study failed to reach this level of daily activity.

The greatest risk of early death was for those individuals who were physically inactive, regardless of the amount of time sitting — they were between 28% and 59% more likely to die early compared with those who were in the most active quartile — a similar risk to that associated with smoking and obesity. In other words, lack of physical activity is a greater health risk than prolonged sitting.

“There has been a lot of concern about the health risks associated with today’s more sedentary lifestyles,” says Professor Ulf Ekelund from the Medical Research Council Epidemiology Unit at the University of Cambridge. “Our message is a positive one: it is possible to reduce — or even eliminate — these risks if we are active enough, even without having to take up sports or go to the gym.

“For many people who commute to work and have office-based jobs, there is no way to escape sitting for prolonged periods of time. For these people in particular, we cannot stress enough the importance of getting exercise, whether it’s getting out for a walk at lunchtime, going for a run in the morning or cycling to work. An hour of physical activity per day is the ideal, but if this is unmanageable, then at least doing some exercise each day can help reduce the risk.”

The researchers acknowledge that there are limitations to the data analysed, which mainly came from participants aged 45 years and older and living in western Europe, the US and Australia. However, they believe that the strengths of the analysis outweigh these limitations. Most importantly, the researchers asked all included studies to reanalyse their data in a harmonized manner, an approach that has never before been adopted for a study of this size and therefore also provides much more robust effect estimates compared with previous studies.

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* Electric assist bikes provide meaningful exercise, cardiovascular benefits for riders

Electric assist bicycles (“pedelecs”) are equipped with a built-in electric motor that provides modest assistance while the rider is actively pedaling, making it easier to cover greater distances and hilly terrain. Pedelecs have steadily grown more popular with consumers over the past decade, especially in Europe and Asia.

While an assist from an electric motor would get a rider disqualified from a competitive cycling competition such as the Tour de France, CU Boulder researchers were interested in studying whether or not pedelecs could help physically inactive non-cyclists achieve recommended daily fitness levels.

To conduct the study, the researchers recruited twenty non-exercising volunteers who were sedentary commuters (car commuters). The researchers tested various aspects of their health, including blood glucose regulation and fitness. The volunteers were then asked to substitute their sedentary commute for riding their pedelec at the speed and intensity of their choice for a minimum of 40 minutes three times per week while wearing a heart monitor and a GPS device.

After a month, the volunteers came back to the lab and had their health tested again. The researchers noticed improvements in the riders’ cardiovascular health, including increased aerobic capacity and improved blood sugar control.

“Commuting with a pedelec can help individuals incorporate physical activity into their day without requiring them to set aside time specifically for exercise,” said James Peterman, a graduate researcher in the Department of Integrative Physiology at CU Boulder and lead author of the new study.

Pedelec bicycles are designed to provide motorized assistance up to speeds of 20 miles per hour. Above that speed, riders must provide all the pedaling power themselves. Based on GPS data, the riders involved in the study rode at an average speed of 12.5 miles per hour and reported no crashes or accidents.

The city of Boulder provided partial funding for the study. Data from the research was provided to the city to assist with the decision on whether or not to allow pedelecs on bike paths.

https://www.sciencedaily.com/ Science Daily

https://www.sciencedaily.com/releases/2016/07/160707142436.htm  Original web page at Science Daily

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How chameleons capture their prey

Despite their nonchalant appearance, chameleons are formidable predators, capturing their prey by whipping out their tongues with incredible precision. They can even capture preys weighing up to 30% of their own weight. In collaboration with the Muséum national d’Histoire naturelle de Paris, researchers from the Université de Mons (UMONS) and the Université libre de Bruxelles (ULB) have studied this amazing sticky weapon.

Chameleons are fascinating creatures with amazing characteristics. Their feet have opposable toes, giving them a tongs-like appearance, to firmly grip branches. Their eyes move independently of each other to provide 360 degree vision. Their skin changes colour via the active tuning of a lattice of nanocrystals contained in some cells. But their most outstanding characteristic is probably their ballistic tongue, allowing the capture of distant preys.

Despite their nonchalant appearance, chameleons are formidable predators, leaving little chance to their prey. During a capture, their tongue whips out with an acceleration up to 1500 m/s² and extends to reach a length twice that of the chameleon’s body. They are also able to capture preys weighing up to 30% of their own weight. Sufficient adhesion between the prey and the tongue is therefore necessary to catch such preys.

Under the leadership of Fabian Brau from the ULB Faculty of Science’s Nonlinear Physical Chemistry Unit, Pascal Damman from the UMONS Interfaces and Complex Fluids Laboratory, Faculty of Science researchers from the UMONS, ULB, and Vincent Bels from the Muséum national d’Histoire naturelle de Paris have just demonstrated that the mucus secreted at the tip of a chameleon’s tongue has a viscosity 400 times larger than the one of human saliva. The tongue’s deformability during projection, producing a large contact area with the prey, together with this viscous liquid, form a particularly efficient adhesive weapon.

Published in the Nature Physics journal on 20 June, this interdisciplinary study, combining experiments with a dynamical model of prey capture, allowed the researchers to shed light on the basic mechanisms used by chameleons to capture their preys.

The authors used mechanical tools combined with tongue morphology measurements to demonstrate that the viscous adhesion built up during a capture is large enough to catch preys with a high mass compared to that of chameleons. Their theoretical model compares favourably with experimental data on the maximum prey mass with respect to the chameleon size.

These results provide a new methodology for studying prey prehension by other predators, such as salamanders or toads, using the tongue to capture preys.

https://www.sciencedaily.com/ Science Daily

https://www.sciencedaily.com/releases/2016/06/160621115647.htm  Original web page at Science Daily

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Changing weather patterns threaten grassland sparrows

Two of North America’s declining grassland songbirds may be particularly vulnerable to altered weather patterns caused by climate change, according to new research in The Condor: Ornithological Applications.

Extreme heat waves have been known to kill adult birds, and droughts can cause birds to abandon nests or skip breeding altogether. To learn what species might be at greatest risk, Jessica Gorzo of the University of Wisconsin-Madison and her colleagues analyzed more than four decades of bird survey data from the Dakotas, Montana, and Wyoming, looking for patterns linking grassland bird abundance to temperature and precipitation.

Of the 14 bird species the researchers focused on, 5 showed significant associations with weather trends, their populations appearing to increase or decrease depending on whether a year had been particularly warm, cold, wet, or dry. Two, the closely related Grasshopper and Baird’s sparrows, are already declining enough to concern conservationists, and this study shows that they may be particularly vulnerable to the warmer, drier conditions that are likely becoming more frequent due to climate change.

“With climate change, there are bound to be winners and losers,” according to Gorzo. “Of the species we considered, Grasshopper and Baird’s Sparrows may be imminently at risk. These species responded similarly to our weather metrics, which made sense in light of their shared life history traits. Knowing that these species need tall, lush grassland vegetation, increasingly dry conditions could inhibit the growth they need to be successful.”

The data for the study came from the North American Breeding Bird Survey, a program for which skilled volunteer birders conduct annual bird counts along set routes. “It was really an honor to work with this dataset, because though I don’t run a route myself, I have many friends who have been visiting the same route year after year and take pride in what they contribute to our understanding of the continent’s birds,” says Gorzo. “It is a tremendous volunteer effort that takes skill, dedication and hard work. To be able to put it to good use to elucidate some patterns relevant to climate change felt really rewarding, and I can’t thank birders over the decades enough for working year in and year out to add to this dataset.”

https://www.sciencedaily.com/ Science Daily

https://www.sciencedaily.com/releases/2016/06/160608095535.htm Original web page at Science Daily

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Early-life stress causes digestive problems and anxiety in rats

Traumatic events early in life can increase levels of norepinephrine — the primary hormone responsible for preparing the body to react to stressful situations — in the gut, increasing the risk of developing chronic indigestion and anxiety during adulthood, a new study in American Journal of Physiology — Gastrointestinal and Liver Physiology reports.

Functional dyspepsia, also known as indigestion with no clear origin, affects an estimated 25 to 40 percent of adults. The most common symptoms include pain or discomfort in the upper abdomen, upset stomach, bloating and feeling full quickly while eating. Because the symptoms cannot be pinpointed to a cause, such as an ulcer or gastritis, functional dyspepsia is challenging to treat and many patients continue to experience symptoms years after diagnosis.

How functional dyspepsia develops is not well understood. Population studies have reported that early-life trauma — including abuse, psychological stress and gastrointestinal infections from sources such as contaminated food and water — increases the risk of developing functional dyspepsia in adulthood. Patients with functional dyspepsia also have a higher prevalence of anxiety, but whether functional dyspepsia and anxiety are linked is a contentious issue.

A research team from the University of Texas Medical Branch at Galveston reported in a previous study that inducing inflammation in the colon — such as what occurs during gastrointestinal infections — of neonatal rats caused gut hypersensitivity when the rats became adults. The researchers found that colon inflammation did so by increasing levels of stress hormone norepinephrine. Norepinephrine is produced in nerves all over the body. When stimulated, the nerves release norepinephrine into the blood stream, which affects cells in the surrounding area. This new study aimed to explain the increase in norepinephrine and determine whether rats were more susceptible to anxiety after having colon inflammation as newborns.

The researchers induced inflammation in the colons of 10-day-old rats. After six to eight weeks, the adult rats were evaluated for stomach hypersensitivity and anxiety-like behavior. The researchers found that colon inflammation increased the levels of tyrosine hydroxylase, a protein that makes norepinephrine, in the nerves in the upper abdomen. The nerves released more norepinephrine, increasing levels of norepinephrine in the upper abdomen. The rats also displayed anxiety-like behavior.

The study shows that increased norepinephrine release in the upper abdomen increases stomach sensitivity and susceptibility to anxiety-like behaviors in rats. “Our findings extend the clinical observations that adverse early-life experiences are risk factors for the development of functional dyspepsia symptoms,” says Sushil Sarna, PhD, of University of Texas Medical Branch at Galveston and lead investigator of the team.

The research group will continue to study the link between functional dyspepsia, anxiety and early-life stress. Anxiety worsens the symptoms of functional dyspepsia, but whether it causes or is a result of functional dyspepsia remains to be investigated, according to Sarna. The experimental method used in this study can be used to answer these questions, Sarna says. The research team is also working to identify potential targets for treating the condition and finding biomarkers to diagnose and evaluate the severity of functional dyspepsia symptoms.

https://www.sciencedaily.com/  Science Daily

https://www.sciencedaily.com/releases/2016/05/160526152213.htm  Original web page at Science Daily

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Tropical birds develop ‘superfast’ wing muscles for mating, not flying

Studies in a group of tropical birds have revealed one of the fastest limb muscles on record for any animal with a backbone. The muscle, which can move the wing at more than twice the speeds required for flying, has evolved in association with extravagant courtship displays that involve rapid limb movements, according to a paper to be published in the journal eLife.

The ‘superfast’ wing movements of male red-capped and golden-crowned manakins are undetectable to the human eye, and are about six to eight times faster than the 8-hertz (Hz) speed at which a sprinter, such as Olympian athlete Usain Bolt, moves their legs through the air in a 100-metre run.

“The discovery of the superfast wing muscle in these birds paves the way for further studies into what has to change, or what can change, in a muscle to make it drive faster movements,” says first author Matthew Fuxjager, from Wake Forest University.

“This could be important for developing therapies for motor disorders, particularly those characterized by decreases in muscle performance that result from diseases such as cancer and HIV.”

Many different species perform rapid limb movements as part of their courtship displays, from certain birds running across lake surfaces, to the unusual boxing displays of hares in March.

However, because muscle performance is limited by trade-offs between speed and force, it is unclear how animals develop the ability to generate both the swift movements involved in showy physical displays and the force needed to drive these movements.

To address this question, Fuxjager and his team compared the twitch speeds of forelimb muscles from wild-caught golden-collared and red-capped manakins to those of three other related species: the blue-crowned manakin, the dusky antbird, and the house wren.

“Of the species studied, the golden-collared and red-capped manakins produce exceptionally rapid wing movements as part of their acrobatic courtship displays,” Fuxjager explains.

“For example, the golden-collared manakins perform ‘roll-snaps’, whereby they hit their wings together above the back at around 60 Hz to produce a loud mechanical sound. Likewise, red-capped manakins produce a similar wing sonation called a ‘clap’, in which the wings are extended slightly above the body and immediately retracted back to the sides in quick succession, at around 45 Hz.”

To explain these birds’ abilities to move their limbs rapidly during courtship performances, the researchers investigated the differences in muscle contraction speeds by comparing the half-relaxation frequency among the five different species. This represents the frequency at which each wing muscle is stimulated to contract, while still being able to relax to half their length following stimulation, thereby showing an accurate measure of how quickly they can contract.

For two of the three wing muscles, the half-relaxation frequencies averaged around 50 Hz and were indistinguishable among species. By contrast, the frequency measures in the main muscle that retracts the humerus were significantly higher in both the golden-collared and red-capped manakins. Estimates of their half-relaxation frequencies in this muscle were exceptionally high, and the frequencies between the two birds were indistinguishable.

These results show that only the golden-collared and red-capped manakins have evolved superfast contractile movements in their main humeral retractor muscle. The other two muscles that generate the majority of aerodynamic force for flight are no different from those of other birds, suggesting that they have been preserved to produce the strength needed for flying.

The team also found that the humeral retractor muscle in golden-collared and red-capped manakins is more than capable of driving the natural wing oscillations that make up their impressive displays.

Taken together, the results suggest that muscle-specific adaptations in contractile speed allow certain birds to avoid the trade-off between muscular speed and force, thereby using their forelimbs for both rapid gestural displays and powered locomotion.

“Further studies could now explore how this one muscle can create such superfast wing movements and whether male hormones, such as testosterone, play a role in regulating the muscle’s speed,” Fuxjager adds.

“If we discover whether steroids regulate the muscle’s ability to contract at superfast speed, we would be uncovering how hormones can ‘turn on’ or ‘turn off’ its extraordinary ability. This would open the door to understanding how rapid limb movements are regulated in accordance with the animals’ reproductive environment.”

https://www.sciencedaily.com/  Science Daily

https://www.sciencedaily.com/releases/2016/04/160412104805.htm  Original web page at Science Daily

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* Pandas hear more than we do

A study published in the journal Global Ecology and Conservation may help field conservationists better understand the potential for human activities to disturb endangered giant pandas in native habitats. Using pandas located at the San Diego Zoo, conservation scientists worked with animal care specialists to determine pandas’ range of hearing sensitivity, discovering that they can detect sound into the ultrasonic range. Because giant pandas depend in large part on information transmitted through vocalizations for reproductive success, noise from human activities in or near forest areas could be disruptive.

“An understanding of a species’ hearing provides a foundation for developing estimates of noise disturbance,” said Megan Owen, associate director of giant panda conservation, San Diego Zoo Global. “For the giant panda, vocalizations are typically emitted in proximity to conspecifics (members of the same species), however the ability to discriminate between fine-scale differences in vocalizations is important for successful reproduction; and so, a thorough understanding of acoustic ecology is merited in order to estimate the potential for disturbance.

“In order to learn about panda hearing, researchers at the San Diego Zoo worked with giant pandas to teach them to respond, if they could hear sounds at a particular pitch and loudness, thus communicating their ability to hear across the acoustic spectrum,” Owen said.

“Through this study, the pandas at the San Diego Zoo have made a significant contribution to our understanding of what may be affecting panda reproduction in habitats in China,” said Ron Swaisgood, director of applied animal ecology, San Diego Zoo Global. “It is only because of the strong relationship that animal care staff have with the bears at the Zoo that we have been able to gather this information.”

https://www.sciencedaily.com/  Science Daily

https://www.sciencedaily.com/releases/2016/03/160322133822.htm  Original web page at Sc

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Simulator-based training in veterinary medicine

Simulator-based training of students at Vetmeduni Vienna has been part of the curriculum since 2012. The Skills Lab is a simulated veterinary practice in which students have the chance to train a variety of veterinary interventions in a near-realistic setup on animal dummies.

But is simulator-based training really as efficient as training on live animals? Christina Nagel, Christine Aurich and their team from Vetmeduni Vienna’s Centre for Artificial Insemination and Embryo Transfer have now analysed for the first time the efficiency of simulator-based training in large animal gynaecology.

Twenty-five third-year veterinary students participated in the study on gynaecological examination of horse mares. Students were randomly allocated to three groups and taught palpation and ultrasonography of the equine genital tract in different ways. Group 1 trained four times on the simulator, consisting of a plastic box shaped like the back-end of a horse with exchangeable rubber genital organs. Group 2 students were trained four times on teaching horses whereas group 3 had only one training session on horse mares.

Two weeks after the last training session, the researchers tested the learning outcomes. All students were asked to examine a horse mare and to make a diagnosis. Students who had trained four times on horses scored best with regard to a correct diagnosis. Students who had been trained only once on horses had the worst results and those trained solely on the simulator scored in between the two other groups. With regard to ultrasonography of the genital tract, there were no major differences between groups.

“Simulator-based training prepares the students very efficiently for diagnostic procedures on live horses,” explains Christina Nagel, principal investigator of the study. “Simulators are, however, not only an additional teaching tool for our students but also a contribution to animal welfare. Only when students have successfully finished the simulator-based training course are they allowed to perform the same diagnostic procedures in animals.”

The stress perceived by horses during gynaecological examinations had already been studied in 2007 by Christine Aurich and her team. Now she was interested in how students feel when examining a horse compared to examining the teaching simulator. Students with previous training on the simulator were less stressed when finally exposed to a live horse. This conclusion is based on recordings of the students’ heart rate and salivary cortisol concentration during the training sessions and tests. The results were published recently in the scientific journal Reproduction in Domestic Animals.

“The results from these studies encourage us to increase the use of teaching simulators for the training of future veterinarians. Repeated training is the best way to improve the students’ diagnostic skills. Our students gain confidence and clinical routine and are thus well-prepared when confronted with clinical cases in the animal hospital. And well-trained veterinary students are also a contribution to animal welfare,” stated Christine Aurich.

http://www.sciencedaily.com/  Science Daily

http://www.sciencedaily.com/releases/2016/01/160115100908.htm  Original web page at Science Daily

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Newfound strength in regenerative medicine

Researchers in the field of mechanobiology are evolving our understanding of health by revealing new insights into how the body’s physical forces and mechanics impact development, physiological health, and prevention and treatment of disease. At the Wyss Institute for Biologically Inspired Engineering at Harvard University, engineers and biomedical scientists have assembled to form collaborative teams that are helping to drive this exciting area of research forward toward real-world applications. Now, a new study suggests mechanically-driven therapies that promote skeletal muscle regeneration through direct physical stimulation could one day replace or enhance drug and cell-based regenerative treatments. Discovered by a team at the Wyss Institute and the Harvard School of Engineering and Applied Sciences, the finding was published on January 25 in the journal Proceedings of the National Academy of Sciences.

“Chemistry tends to dominate the way we think about medicine, but it has become clear that physical and mechanical factors play very critical roles in regulating biology,” said Harvard bioengineer David Mooney, Ph.D., senior author on the new study, who is a Wyss Institute Core Faculty member and the Robert P. Pinkas Family Professor of Bioengineering at the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS). “The results of our new study demonstrate how direct physical and mechanical intervention can impact biological processes and can potentially be exploited to improve clinical outcomes. ”

In humans, up to half of body mass is made up of skeletal muscle, which plays a key role in locomotion, posture, and breathing. Although skeletal muscles can overcome minor tears and bruising without intervention, major injuries commonly caused by motor vehicle accidents, other traumas, or nerve damage can lead to extensive scarring, fibrous tissue, and loss of muscle function.

The team applied combined murine models of muscle injury and hind limb ischemia to investigate two potential mechanotherapies: an implanted magnetic biocompatible gel and an external, soft robotic pressurized cuff. To alleviate severe muscle injuries, the team implanted a magnetized gel called a “biphasic ferrogel” so that it would be in direct contact with the damaged tissue. Another experimental group of mice did not receive the ferrogel implant, but instead were fitted with a soft robotic, non-invasive pressurized cuff over the injured leg. Then, the ferrogel was subjected to magnetic pulses to apply cyclic stimulation to the muscle, while pulses of air allowed the cuff to cyclically massage the hind leg. Both groups received two weeks of localized mechanical perturbation using the two distinct methods.

The researchers discovered that cyclic mechanical stimulation provided by either magnetized gel or robotic cuff both resulted in a two-and-a-half-fold improvement in muscle regeneration and reduced tissue scarring over the course of two weeks, ultimately leading to an improvement in regained muscle function and an exciting new finding that mechanical stimulation of muscle alone can foster regeneration. To their surprise, the ferrogel implant and pressurized cuff also resulted in very similar levels of regeneration, suggesting that the use of non-invasive pressurized cuffs or devices could one day help heal patients suffering from severe muscle injuries.

“Until now most approaches to muscle regeneration have been biologic, relying on the use of drugs or cells,” said Christine Cezar, Ph.D., lead author on the study who completed her doctoral research at the Wyss Institute and Harvard SEAS. “Our finding that mechanical stimulation alone is enough to enhance muscle repair could open the door to new non-biologic therapies, or even combinatorial therapies that employ both mechanical and biological interventions to treat severely damaged skeletal muscles.”

The direct stimulation of muscle tissue increases the transport of oxygen, nutrients, fluids and waste removal from the site of the injury, which are all vital components of muscle health and repair. And according to Mooney, one of the most exciting aspects of this research is that its translation to the clinic in the form of a stimulatory device could be relatively rapid as compared to drug or cell therapies.

Down the road, the principle of using mechanical stimulation to enhance regeneration or reduce formation of scarring or fibrosis could also be applied to a wide range of medical devices that interface mechanical components with body tissues. Currently, clinical devices are often plagued by the formation of thickened tissue capsules that form at the intersection of machine and man. The team plans to explore how the findings can make the jump from the laboratory to the clinic.

“This work clearly demonstrates that mechanical forces are as important biological regulators as chemicals and genes, and it shows the immense potential of developing mechanotherapies to treat injury and disease,” said Wyss Institute Founding Director Donald Ingber, M.D., Ph.D., who is a pioneer and leader in the field of mechanobiology.

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http://www.sciencedaily.com/releases/2016/01/160125185041.htm  Original web page at Science Daily

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Researchers work on lowering greenhouse gas emissions from poultry houses

The University of Delaware’s Hong Li is part of a research team looking at how adding alum as an amendment to poultry litter reduces ammonia and greenhouse gas concentrations and emissions, specifically carbon dioxide, in poultry houses.

Li partnered with researchers at the United States Department of Agriculture (USDA), the University of Tennessee and Oklahoma State University for the project and the results of the research were recently published in the Journal of Environmental Quality.

Li, assistant professor in the Department of Animal and Food Sciences (ANFS) in UD’s College of Agriculture and Natural Resources, said that the project is ongoing and that the main challenge for the poultry industry is controlling nutrient emissions from poultry houses and conserving energy while also providing for the welfare of the birds inside the houses.

Acid-based chemical compounds, alum and PLT — another amendment — that are added to the bedding material in poultry houses prior to the birds entering have proven to be a very effective tool in controlling ammonia emissions.

“In the poultry industry, ammonia is a major concern. Ammonia during the growth period is high, especially during the wintertime. Ammonia can do a lot of damage to the animal, especially the respiratory system, and can effect overall animal health and welfare,” said Li.

Also, if ammonia is emitted to the air from the poultry house, it is a precursor of fine particles and there are national Clean Air Act regulations from the Environmental Protection Agency that have strict guidelines for controlling emissions.

“We need to control the ammonia, not only for the animal health but also for the public health. That’s why I’m doing the research, to reduce the ammonia emissions and improve the animal health and the public air quality, especially for the rural areas, to make sure our agriculture is sustainable,” said Li.

Li said that there are several products on the market to control ammonia in poultry houses and alum is the preferred product for growers in Arkansas, where the study was conducted.

While adding alum to poultry litter is known to reduce ammonia concentration in poultry houses, its effects on greenhouse gas emissions had been unknown.

Li’s role in the study was on the engineering side and he helped Philip Moore, one of the authors of the paper and a pioneer researcher on alum in poultry production with the USDA, develop an automatic air sampling system to evaluate the emissions reduction by using alum in the broiler house.

“We not only looked at ammonia reduction, we also looked at the whole environmental footprint — how the alum could potentially impact the greenhouse emissions — and the results showed that we reduced quite a bit of carbon dioxide emissions,” said Li.

The carbon dioxide was reduced in two ways. First, because alum is an acidic product, it reduces microbial activity in the litter and reduces the ammonia emissions.

Ammonia comes from uric acid being broken down by bacteria and enzymes. Once the uric acid is broken down, two products are created — one is ammonia and one is carbon dioxide.

“By reducing the bacterial activity, we reduce ammonia and also we reduce the carbon dioxide; that’s one aspect of how we reduce carbon dioxide,” said Li.

Second, by using acid-based litter amendments in poultry litter, growers can reduce the ventilation rate and reduce fuel used for heating the poultry houses, especially during the winter.

“In the broiler industry, we want to control ammonia to improve animal health and welfare. They have to keep the bird comfortable with optimum temperatures. However, if you want to have lower ammonia, you have to bring in more fresh air, remove more of the ammonia-laden air. As a result, you have to over ventilate the house,” Li said.

“That means you have to burn more fuel to keep the house warm. By using the acid-based litter amendments, we can reduce the ventilation rate and the fuel use, which reduces the carbon dioxide emission from the house through the heating process. Basically, if we reduce the microbial activity and also reduce the heating, we can generate lower carbon dioxide emissions.”

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http://www.sciencedaily.com/releases/2016/01/160112125514.htm  Original web page at Science Daily

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Singing in the brain: Songbirds sing like humans

A songbirds’ vocal muscles work like those of human speakers and singers, finds a study recently published in the Journal of Neuroscience. The research on Bengalese finches showed that each of their vocal muscles can change its function to help produce different parameters of sounds, in a manner similar to that of a trained opera singer.

“Our research suggests that producing really complex song relies on the ability of the songbirds’ brains to direct complicated changes in combinations of muscles,” says Samuel Sober, a biologist at Emory University and lead author of the study. “In terms of vocal control, the bird brain appears as complicated and wonderful as the human brain.”

Pitch, for example, is important to songbird vocalization, but there is no single muscle devoted to controlling it. “They don’t just contract one muscle to change pitch,” Sober says. “They have to activate a lot of different muscles in concert, and these changes are different for different vocalizations. Depending on what syllable the bird is singing, a particular muscle might increase pitch or decrease pitch.”

Previous research has revealed some of the vocal mechanisms within the human “voice box,” or larynx. The larynx houses the vocal cords and an array of muscles that help control pitch, amplitude and timbre.

Instead of a larynx, birds have a vocal organ called the syrinx, which holds their vocal cords deeper in their bodies. While humans have one set of vocal cords, a songbird has two sets, enabling it to produce two different sounds simultaneously, in harmony with itself.

“Lots of studies look at brain activity and how it relates to behaviors, but muscles are what translates the brain’s output into behavior,” Sober says. “We wanted to understand the physics and biomechanics of what a songbird’s muscles are doing while singing.”

The researchers devised a method involving electromyography (EMG) to measure how the neural activity of the birds activates the production of a particular sound through the flexing of a particular vocal muscle.

The results showed the complex redundancy of the songbird’s vocal muscles. “It tells us how complicated the neural computations are to control this really beautiful behavior,” Sober says, adding that songbirds have a network of brain regions that non-songbirds do not.

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http://www.sciencedaily.com/releases/2016/01/160112125411.htm  Original web page at Science Daily

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Brazilian torrent frogs communicate using sophisticated audio, visual signals

Brazilian torrent frogs may use sophisticated audio and visual signals to communicate, including inflating vocal sacs, squealing, and arm waving, according to a study published January 13, 2016 in the open-access journal PLOS ONE by Fábio P. de Sá, Universidade Estadual Paulista, Brazil, and colleagues.

Frog communication plays a role in species recognition and recognition of potential rivals or mates. The authors of this study investigated communication in the Brazilian torrent frog, an endemic frog to Brazil a frog endemic to Brazil, where males are known to be territorial and display elaborate courtship behavior. The researchers observed nearly 70 male and female torrent frogs over a period of 15 months.

The researchers observed a complex repertoire of acoustic and visual displays during advertisement, including long-range, short-range, and courtship communication with other frogs. During courtship, the authors observed males performing visual displays using their toes, feet, hands, legs, arms, vocal sacs, head, and body while females only displayed hand, arm, and body movements. They also describe a behavior previously unknown in frogs, where females use a combination of visual displays and touch to stimulate the male’s courtship call. They also found that frogs may choose to signal with their left or right limbs, and that males can choose which of their two vocal sacs to use for visual signaling. Torrent frogs also exhibit a diverse acoustic repertoire that, besides the advertisement call, include peeps, squeals, and courtship calls.

The authors suggest their results indicate that Brazilian torrent frogs have one of the most diverse repertoires of visual and audio displays known to frogs, indicating that communication in torrent frog species is likely more sophisticated than previously thought.

Dr. Fábio P. de Sá adds “Our study indicates that communication in species of the genus Hylodes is more sophisticated than expected. Also we suggest that communication in frogs is more complex than thought. Likely, that is particularly true for tropical areas, where there is a higher number of species and phylogenetic groups and/or where there is higher microhabitat diversity.”

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http://www.sciencedaily.com/releases/2016/01/160113160646.htm  Original web page at Science Daily

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How variation in body size correlates with en-route migration performance in a long-distance migratory songbird?

Researchers relate migration performance to body and wing size in migratory songbirds. The original article “The influence of morphological variation on migration performance in a trans-hemispheric migratory songbird” is available to read and download fully in open access on De Gruyter Online.

Every spring and fall, migratory songbirds around the world make epic journeys from their breeding to their wintering grounds. Ornithologists have long known that not all birds travel at the same speed during the treks, as some individuals tend to stay longer at stopover sites than others. The reason for the varying stopover lengths has usually been attributed to differences in feeding rates. Now, a team of Canadian researchers from the University of Manitoba has determined there is another, very surprising, reason why some birds stay longer at stopover sites than others. In an article, just published in Animal Migration, they conclude that, apparently, it is the physical structure of the birds that determines their performance.

The researchers, led by Lawrence Lam from the University of Manitoba, studied the migrations of individual Purple Martins — small songbirds related to swallows, known for colonial-nesting in Martin houses and hollowed-out gourds. They placed tiny tracking devices (light-level geolocators) on 120 martins from 10 different breeding sites across North America and then recaptured them after the birds had completed their migration. The devices not only provide information on where the birds go during their northward and southward journeys, but they also tell, how long they stay at stopover sites on route.

Eager to determine if body or wing size played role in the migratory rates of the martins, the scientists collected detailed measurements of each bird before they released it. They then compared the birds’ individual body measurements against the number and duration of their stopover periods during the fall and spring migrations. Their analyses demonstrated that larger-bodied birds tend to stay longer at stopover sites during fall migration, but during spring the larger birds actually have shorter and fewer stopovers. In other words, the individual variation in stopover length is influenced by the size of the bird, and by the size of its wings.

“As far back as the late 1800’s, researchers noticed that migratory birds differed in size and shape than non-migratory birds, and they suggested that these features may be beneficial to migrants” comments Dr. Melissa Bowlin of the University of Michigan-Dearborn, who also utilizes tracking technologies in her research of migratory flight performance. Now we know “that smaller-bodied birds were able to migrate faster in autumn,” she adds. “While this is just a first step, analyses such as these should allow us to tease apart the effects (if any) of some of the morphological variables that have been associated with migration for so many years.”

It is yet unclear, if these findings apply to other long-distance migrants, but the current results already pave the way for future investigations on the linkages between physical characteristics and migration performance. The authors recommend that, when studying the migration ecology of long-distance migratory birds, researchers should include information regarding how foraging ability and other factors may impact migratory performance.

“A lot of researchers are now using geolocators to track bird migrants,” says Andy Davis, Editor-in-Chief of Animal Migration, “but this study is the first to combine migration tracking information with individual flight characteristics, and it shows these things are related.”

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http://www.sciencedaily.com/releases/2016/01/160113144602.htm  Original web page at Science Daily

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Precise method underlies sloppy madness of dog slurping

Stories about lap dogs are everywhere, but researchers at the Virginia Tech College of Engineering can tell the story of dog lapping.

Using photography and laboratory simulations, researchers studied how dogs raise fluids into their mouths to drink. They discovered that sloppy-looking actions at the dog bowl are in fact high-speed, precisely timed movements that optimize a dogs’ ability to acquire fluids. Their discovery appears today in the Proceedings of the National Academy of Sciences.

Researchers also compared what they learned about how dogs drink with what they knew from previous studies of cats. The scientists discovered that even though feline and canine mouths structurally are similar, their approaches to drinking are as different as — cats and dogs.

“We know cats and dogs are quite different in terms of behavior and character,” said Sunghwan “Sunny” Jung, an associate professor of biomedical engineering and mechanics. “But before we did fundamental studies of how these animals drink fluids, our guess was dogs and cats drink about the same way. Instead we found out that dogs drink quite differently than cats.”

Dogs and cats are biting animals and neither have full cheeks. But without cheeks, they can’t create suction to drink — as people, horses, and elephants do. Instead they use their tongues to quickly raise water upward through a process involving inertia.

Both animals move their tongues too quickly to completely observe by the naked eye. But dogs accelerate their tongues at a much faster rate than cats, plunging them into the water and curling them downward toward their lower jaws, not their noses.

They quickly retract their tongues and a column of water forms and rises into their mouths, but they also curl the underside of their tongues to bring a tiny ladle of water upward.

Dogs precisely bite down to capture the water. In an instant they reopen their mouths and immerse their tongues back into the water.

Cats, on the other hand, lightly touch the surface of the water with their tongues, usually never fully immersing them, according to previous imaging by Jung and other researchers. When their tongues rise into their mouths, liquid adheres to the upper side, forming an elegant water column.

When dogs accelerate their tongues upwards, the latest research reveals a water column rising, but some water remains in the ladle of the tongue and is tossed to either side of the dog’s mouth.

Although dogs do not use their tongues to actively scoop water into their mouths, it is possible that the scooped liquid has some positive effect on the water column dynamics below the tongue, the researchers said.

“Dog drinking is more acceleration driven using unsteady inertia to draw water upward in a column, where cats employ steady inertia,” Jung said.

In all, 19 dogs of various sizes and breeds were volunteered for filming by their owners. Thirteen of the dogs were filmed outdoors at their owners’ residences in the Blacksburg, Virginia, area. The remaining six were filmed at the Virginia Tech campus.

“This was a basic science study to answer a question very little was known about — what are the fundamental mechanics of how dogs drink?” said Sean Gart, a graduate student in biomedical engineering and mechanics who filmed the dogs. “Cats tend be viewed as neater, dogs are messier, but dogs really have to accelerate their tongues to exploit the fluid dynamics of the water column.

The researchers measured tongue motion, recorded water volumes, and generally measured lapping in the dogs. They used the results to generate a physical model in the laboratory of the tongue’s interaction with the air-fluid interface, according to Jake Socha, an associate professor of biomedical engineering and mechanics at Virginia Tech.

Pavlos Vlachos, a professor of mechanical engineering at Purdue University, also participated in the study.The research, supported by the National Science Foundation, is an accomplishment of the Bio-Inspired Fluid Lab of the Virginia Tech College of Engineering. The lab seeks to take cues from living systems to make practical applications that exploit the natural movement of fluids.

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http://www.sciencedaily.com/releases/2015/12/151214165730.htm  Original web page at Science Daily

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Brainstem ‘stop neurons’ make us halt when we walk

Locomotion is an essential motor behaviour needed for survival in both humans and animals. It has an episodic nature: we move when we want or need and, equally well, we can terminate ongoing movements. This episodic control has generally been attributed to descending excitatory signals in the brainstem that contact and activate neuronal circuits in the spinal cord. But is the stop of locomotion only due to a lack of activating signals from the brainstem or is there a dedicated stop signal?

In the present study, the researchers Julien Bouvier and Vittorio Caggiano together with Professor Ole Kiehn and colleagues studied how the complex brainstem neuronal circuits control locomotion in mice. They used advanced methods, including optogenetics, which makes it possible to selectively activate specific groups of neurons with light, as well as genetic silencing to selectively block neuronal activity.

Somewhat unexpectedly, they found a population of excitatory neurons that turned out to be essential for the ability of mice to stop. When those ‘stop cells’ are activated, mice immediately halt their locomotion. Conversely, when those neurons are silenced, mice had difficulties when trying to stop walking.

“We found that the stop cells depress the neuronal networks involved in generating the locomotor rhythm, the clock in the network, and not the motor neurons that directly contract muscles”, says Ole Kiehn, who leads the laboratory behind the study at Karolinska Institutet’s Department of Neuroscience. “In this way activity in the stop cells allows the animal to make a gracious stop without losing its muscle tone, just as we experience ourselves when we voluntarily stop for example in front of an obstacle.”

Although the study addresses the normal brain function the findings may provide insights to how locomotion is affected in the diseased brain. “For example, in Parkinson’s disease, a pronounced motor symptom is a gait disturbance with freezing of the gait”, says Ole Kiehn. “t is possible that the stop cells have an abnormally increased activity in Parkinson’s disease, contributing to the gait disturbances.”

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http://www.sciencedaily.com/releases/2015/11/151119133244.htm  Original web page at Science Daily

 

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* Hummingbirds rely on raw power, not physique, to outmaneuver rivals

Brute strength is surprisingly important to the ability of hummingbirds to outmaneuver rivals for nectar and evade predators, according to new University of British Columbia research published in eLife. An intensive study of 20 Anna’s hummingbirds, Calypte anna, led by the University of British Columbia, revealed that birds with the highest muscle capacity are able to accelerate faster and make more demanding, complex turns.

“We had expected wing morphology and body mass to have more of an influence on maneuverability so were surprised that muscle capacity is so important,” says Doug Altshuler, lead author from the University of British Columbia.

The scientists will repeat the experiments with other tropical species that have greater variation in body mass and wing morphology. These field studies will help determine whether the findings are common to other hummingbirds.

The muscle capacity of the birds was determined by attaching a necklace of weighted beads to each bird. Hummingbirds are able to fly directly upwards, and their maximum weight-lifting ability could be measured by how many of the beads they were able to lift. A two-hour solo flight of each bird was filmed to record and analyse their aerial displays.

For hummingbirds, the burst capacity of their muscles has an important evolutionary function. Their natural escape response is to fly vertically. They might need to employ this while hovering at a flower to feed. So, in addition to the power needed to hover normally, they need a reserve of power to accelerate away from predators or competitors. Competition within species can be severe, with birds defending a patch of individual flowers for access to nectar and often using their bills as daggers to stab other birds in flight.

Such airborne combat could explain why the birds in the study deployed some extra dazzling moves when paired. These competition trials, filmed over an additional two hours, involved chases, displacements and aerial displays but very little direct contact. Paired birds were found to use more arcing turns than pitch-roll turns in the presence of a competitor. Pitch-roll turns require the birds to slow down, which may make them a target for aggression by a competitor. The scientists believe they prefer arcing terms during competition so that they are always on the move when in flight.

They had expected to see even greater effects of competition, such as higher acceleration. However, they found that the paired birds actually accelerated more slowly during horizontal flight. This may be a result of the experiment being carried out in a chamber rather than in the wild. The benefit of this approach is that a large number of measurements from the same individuals can be combined with other data, allowing the new insights to be uncovered.

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http://www.sciencedaily.com/releases/2015/11/151119103304.htm  Original web page at Science Daily

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Adapting to -70 degrees in Siberia: A tale of Yakutian horses

From an evolutionary perspective it happened almost overnight. In less than 800 years Yakutian horses adapted to the extremely cold temperatures found in the environments of eastern Siberia. The adaptive process involved changes in the expression of a plethora of genes, including some also selected in human Siberian groups and the extinct woolly mammoth.

In a new scientific study, the comparison of the complete genomes of nine living and two ancient Yakutian horses from Far-East Siberia with a large genome panel of 27 domesticated horses reveals that the current population of Yakutian horses was founded following the migration of the Yakut people into the region in the 13-15th century AD. Yakutian horses, thus, developed their striking adaptations to the extreme cold climate present in the region in less than 800 years. This is one of the fastest examples of adaptation within mammals. The findings are reported in the PNAS early edition from November 23rd by an international team of researchers led by Dr. Ludovic Orlando from the Centre for GeoGenetics at the Natural History Museum of Denmark, University of Copenhagen.

Horses have been essential to the survival and development of the Yakut people, who migrated into the Far-East Siberia in the 13-15th century AD, probably from Mongolia. There, Yakut people developed an economy almost entirely based on horses. Horses were indeed key for communication and keeping population contact within a territory slightly larger than Argentina, and with 40 % of its surface area situated north of the Arctic Circle. Horse meat and hide have also revealed crucial for surviving extremely cold winters, with temperatures occasionally dropping below -70C.

Horses have been present in Yakutia for a long time as 30,000 year-old Late Pleistocene fossils from the region show. Yet, Dr. Ludovic Orlando and his team now reveal that ancient horses of this region were not the ancestors of the present-day Yakutian horses.

The genome sequence obtained from the remains of a 5,200 year-old horse from Yakutia appears within the diversity of a now-extinct population of wild horses that the team discovered last year in Late Pleistocene fossils from the Taymir peninsula, Central Siberia. This new finding extends by thousands of kilometers eastwards the geographical range of this divergent horse population, which became separated from the lineage leading to modern horses some 150,000 years ago. It also extends its temporal range up to 5,200 years ago, a time when woolly mammoths also became extinct. Dr. Ludovic Orlando says: “This population did not appear on any radar until we sequenced the genomes of some of its members. With 150,000 years of divergence with the lineage leading to modern horses, this makes the roots of this population as deep as the origins of our human species.

Interestingly, the new genome analyses show that the horses that Yakut people now ride and probably rode all along their history (as shown by the genome of a ~200 year-old horse), are not related with this now-extinct horse lineage, but rather with the domesticated horses from Mongolia. Dr. Ludovic Orlando says: “We know now that the extinct population of wild horses survived in Yakutia until 5,200 years ago. Thus it extended from the Taymir peninsula to Yakutia, and probably all across the entire Holarctic region. In Yakutia, it may have become extinct prior to the arrival of Yakut people and their horses. Judging from the genome data, modern Yakutian horses are no closer to the extinct population than is any other domesticated horse.”

The new genome analyses show that the founders of the modern Yakutian horse population probably entered into the region with Yakut horse-riders in the 13-15th Century AD. Dr. Ludovic Orlando further adds: “This is truly amazing as it implies that all traits now seen in Yakutian horses are the product of very fast adaptive processes, taking place in about 800 years. This represents about a hundred generations for horses. That shows how fast evolution can go when selective pressures for survival are as strong as in the extreme environment of Yakutia.

The team leveraged on their large horse genome panel to identify the genes underlying such adaptations. Strikingly, they found that a large fraction of the selection signatures were not located within the coding region of genes, but within their upstream regulatory regions. It, thus, suggests that the adaptation of Yakutian horses to their environment took place through a massive reprogramming of gene expression. Dr. Pablo Librado comments: “The founder group of the current population was quite reduced in size. The genetic variation standing within gene bodies was, thus, probably limited in comparison to that present within regulatory regions. These regulatory variants probably offered as many possibilities to rapidly modify horse traits in a way that was compatible with their survival.”

Focusing on the genes and their regulatory regions showing evidence of selection, the team identified key biological functions involved in the adaptive process. These concern morphological changes, hormonal responses involved in the regulation of thermogenic requirement and the production of anti-freezing compounds. The list of selective signatures also include genes, such as TGM3, which is involved in hair development and might be responsible for the extremely hairy winter coat of Yakutian horses. Dr. Librado adds: “In addition to unveil their evolutionary origins, our approach helped narrow down the genetic basis of adaptations that are unique to Yakutian horses. In one word, their genetic makeup. We also found genes that were reported to have undergone selection in other Arctic populations, such as indigenous Siberian humans, and even the woolly mammoth. It provides a compelling example of evolutionary convergence, where unrelated groups exposed to similar environments end up independently developing similar adaptations.”

Such genes showing convergent signals of adaptation include in humans PRKG1, which is involved in the shivering response to cold, and BARX2 in the woolly mammoth which is involved in hair development.

Dr. Clio Der Sarkissian concludes: “Our work shows the power of ancient DNA, as we would have never been able to discover the existence of the now extinct ancient population of horses by analyzing the genome of modern horses. With ancient genomes, we can now understand the dynamics of past populations at unprecedented levels and track, through space and time, how these became adapted to changing environments. Applied to pre-industrial museum specimens, our approach can therefore help following how extant populations have been affected by ongoing climate changes and recent human activities. This can help develop tailor-made conservation programs, which will be ultimately essential for preserving endangered populations.” The group has already implemented such approaches for preserving the Przewalski’s horse, which represents the last truly wild horse living in the planet.

http://www.sciencedaily.com/  Science Daily

http://www.sciencedaily.com/releases/2015/11/151123201922.htm  Original web page at Science Daily

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* Nerve cells warn brain of damage to inner ear

Some nerve cells in the inner ear can signal tissue damage in a way similar to pain-sensing nerve cells in the body, according to new research from Johns Hopkins. If the finding, discovered in rats, is confirmed in humans, it may lead to new insights into hyperacusis, an increased sensitivity to loud noises that can lead to severe and long-lasting ear pain.

“We are still a long way from being able to treat hyperacusis,” says Paul Fuchs, Ph.D., professor of otolaryngology-head and neck surgery, neuroscience and biomedical engineering at the Johns Hopkins University School of Medicine, “but our results suggest that cells called type II afferent neurons are similar to pain-sensing neurons in the rest of the body, so lessons about interventions elsewhere could apply to the ear, too.” A summary of the research was published online in the journal Proceedings of the National Academy of Sciences during the week of Nov. 9.

The new discovery came as a result of interest in why this small subset of afferent nerve cells — nerves that take information from the inner ear to the brain — are quite insensitive to sound. “If they aren’t very good at relaying sounds, what are they doing?” says Fuchs.

Fuchs and his team knew that these type II afferents connect to specialized sensory cells in the ear of mammals. These so-called outer hair cells amplify the sound waves that enter the inner ear, giving mammals very sensitive hearing over a wide range of frequencies. But, according to Fuchs, this specialization comes at a cost.

“Outer hair cells are the canaries in the coal mine for the inner ear, in that they’re the first cells to die due to loud noise, age or other factors,” says Fuchs. “Since they can’t regenerate, their death leads to permanent hearing loss.” So one possible role for type II afferents, he adds, would be to warn the brain of impending damage to outer hair cells.

It was known that nearby supporting cells respond to outer hair cell damage by increasing their inner calcium levels and releasing the chemical messenger ATP. Fuchs’ team knew that type II afferent neurons can respond to ATP, so they damaged outer hair cells while monitoring type II neurons in surgically removed inner ear tissue. Indeed, outer hair cell rupture caused robust excitation of type II neurons.

Fuchs says that the ATP released by the supporting cells is probably what gets the neurons to fire, and the supporting cells might release ATP in response to ATP that leaks out of the ruptured outer hair cells. But he noted that “outer hair cells don’t have to rupture to release ATP. Progressive damage caused by loud noises or other stress is enough to increase ATP levels in the fluid of the inner ear.”

Over evolutionary time, such a mechanism could have evolved to help mammals avoid further damage to their hearing. Such effects might depend on heightened sensitivity of the type II neurons after trauma, akin to the heightened sensitivity of pain-sensing nerves in damaged skin. Hypersensitivity to loud sound (hyperacusis) is a paradoxical consequence of hearing loss in many people. Everyday noises such as slamming doors, clanking dishes and barking dogs can become irritating and even painful.

The good news, Fuchs says, is that the analogies with pain elsewhere in the body provide guidance for future studies. For example, a compound that suppresses pain-sensing nerve cells elsewhere, also prevented type II afferent neurons from firing in response to outer hair cell death. At present, Fuchs cautions, this is a restricted experimental result. But, it provides a “proof of concept” for treating pain associated with inner ear damage. And the Fuchs laboratory plans to explore this question in their ongoing research.

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http://www.sciencedaily.com/releases/2015/11/151109182050.htm  Original web page at Science Daily

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* Vulture’s scavenging secrets: Ironclad stomach, strong immune system

Vultures have a unique genetic make-up allowing them to digest carcasses and guard themselves against constant exposure to pathogens in their diet, according to the first Eurasian vulture genome published in the open access journal Genome Biology. The study also finds that this species of Asian vulture is more closely related to the North American bald eagle than previously thought.

The cinereous vulture or black vulture, Aegypius monachus, is the largest bird of prey, and an iconic bird in the Far East. The species plays a key role in the ecosystem by removing rotting carcasses, thus preventing the spread of disease.

As their feeding habits involve constant exposure to pathogens, vultures are suspected to have strong immune systems, having evolved mechanisms to prevent infection by the microbes found in their diet. Despite the potential interest in the immune system of scavengers, little is known about the genetic variations involved in vultures’ immune processes.

Lead author Jong Bhak from Ulsan National Institute of Science and Technology, South Korea, said: “This is the first Old World vulture genome that has been reported, and we can see that the cinereous vulture has genetic signatures for resisting infection from eating decaying flesh. Understanding the genetic make-up of extreme life forms has potential for improving human health. The immune system genes we’ve identified could be useful targets in humans for protection against infection.”

The team sequenced the genome of a cinereous vulture, and compared it to that of the closely-related bald eagle, the national bird of the United States, to find genetic signatures of the dietary and environmental adaptations that help enable the vulture’s scavenging lifestyle.

Specifically, they found variations in genes related to the regulation of gastric acid secretion, consistent with their ability to digest carcasses. Other genetic variations included several in genes associated with immunity and defense against microbial and viral infections.

These included genes that allow cells to take up microorganisms and target pathogens for ingestion and elimination. The authors suggest that these may play a role in helping the vulture species combat pathogens encountered in their diet and complement the role of gastric secretion.

The term vulture refers to two groups of birds of prey that evolved independently, namely the Old World vultures, found in Africa, Asia and Europe, and the New World vultures, found in the Americas.

By analyzing its full genome, the researchers calculated that the Old World cinereous vulture species diverged from the North American bald eagle species around 18 million years ago. This split is much more recent than the divergence of the Old World and New World vultures around 60 million years ago. The results therefore add further evidence to the hypothesis that the two groups of vultures evolved their similar features and lifestyle independently in different locations.

http://www.sciencedaily.com/  Science Daily

http://www.sciencedaily.com/releases/2015/10/151021083143.htm  Original web page at Science Daily

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Cats retain multiple functional bitter taste receptors

The bitter truth: Kitty’s picky eating habits further unravelled. According to new research from the Monell Center, cats have at least seven functional bitter taste receptors. Further, a comparison of cat to related species with differing dietary habits reveals that there does not appear to be a strong relationship between the number of bitter receptors and the extent to which a species consumed plants in its diet. The findings question the common hypothesis that bitter taste developed primarily to protect animals from ingesting poisonous plant compounds.

“Alternate physiological roles for bitter receptors may be an important driving force molding bitter receptor number and function. For example, recent Monell-related findings show that bitter receptors also are involved in protecting us against internal toxins, including bacteria related to respiratory diseases,” said study author Gary Beauchamp, PhD, a behavioral biologist at Monell.

Scientists speculate that the sense of taste evolved so animals could make the critical decision of whether a potential food is nutritionally advantageous or possibly harmful. For example, sweet taste is believed to signal the presence of sugars, an important source of energy. Similarly, scientists have long assumed that bitter taste evolved as a defense mechanism to detect potentially harmful toxins commonly found in plants.

In support of the sweet taste hypothesis, Monell scientists previously found that both domestic and wild cats are unable to taste sweet compounds. This inability reflects damage to an underlying gene for the sweet taste receptor. The researchers theorized that the strictly meat-eating cats lost their ability to taste sweetness because they have no need to detect sugars.

Additional findings from Monell revealed that other exclusively carnivorous mammals, including sea lions and spotted hyenas, also have lost the ability to detect sweet taste.

The current study, published in the open access journal PLOS ONE, used a similar rationale to ask whether cats, which typically do not eat plants, have maintained the ability to detect bitter taste.

Unlike sweet taste, which has only one or perhaps two different receptor types, the number of functional bitter taste receptor types — those that are able to respond to bitter compounds — varies greatly across species.

If bitter detection evolved to detect plant toxins, the scientists expected to find fewer functional bitter receptors in strictly carnivorous animals like cats and more functional bitter receptors in related species that eat more plants.

In the study, the researchers first examined DNA from domestic cats and identified 12 different genes for cat bitter receptors.

The Monell scientists next evaluated whether these genes encode functional bitter receptors. To do this, they incorporated the gene sequence of each receptor into cultured cells and then probed the cells to determine if they were activated by one or more of 25 different bitter-tasting chemicals.

Using this method, the researchers confirmed that at least seven of the 12 identified cat bitter receptor genes are functional, meaning that they have the ability to detect at least one bitter chemical. The remaining five bitter receptors may respond to bitter compounds not tested, so it is not possible to determine their functional status without additional studies.

To provide a comparative perspective on the relationship between diet and bitter receptor function, the researchers used previously published data to compare the number of bitter receptor types in cats to that of related species. Relative to the 12 receptors identified in cat, dog (15 receptors), ferret (14), giant panda (16), and polar bear (13) all had a similar number of bitter receptors. Like cats, these species all belong to the order Carnivora. However, they differ considerably with regard to diet, ranging from strictly carnivorous (cat) to omnivorous (dog) to exclusive plant eaters (giant panda).

Thus, unlike sweet receptors, which seem to be non-functional in many exclusively meat-eating Carnivora species, there does not appear to be a strong relationship between the number of bitter receptors and the extent to which a Carnivora species consumed plants in its diet.

However, it remains possible that bitter taste could have a protective function related to feeding behavior. “For example, bitter taste could exist to minimize intake of toxic compounds from skin and other components of certain prey species, such as invertebrates, reptiles and amphibians,” says Beauchamp

On a positive note, the bitter results from the current study could have a pleasurable effect for the family cat. “Cats are known as picky eaters,” said Monell molecular biologist and study lead author Peihua Jiang, PhD. “Now that we know that they can taste different bitters, our work may lead to better formulations of cat food that eliminate the bitter off-taste associated with certain flavors and nutrients.”

http://www.sciencedaily.com/  Science Daily

http://www.sciencedaily.com/releases/2015/10/151021144650.htm  Original web page at Science Daily

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Activity could help keep knees lubricated

Cartilage is filled with fluid — about 80% of the volume of the cartilage tissue — that plays the essential roles of supporting weight and lubricating joint surfaces. Loss of this fluid, called synovial fluid, results in a gradual decrease in cartilage thickness and increase in friction, which is related to the degradation and joint pain of osteoarthritis.

Since cartilage is porous, fluid is readily squeezed out of the holes over time. Yet the symptoms associated with osteoarthritis usually take decades to develop.

“The important question is why cartilage doesn’t deflate over the course of days, months or years in our joints,” said David Burris, an assistant professor in the Mechanical Engineering Department at the University of Delaware. Burris and his colleagues have proposed a mechanism that explains how motion can cause cartilage to reabsorb liquid that leaks out. Burris will speak about his research during the AVS 62nd International Symposium and Exhibition, held Oct. 18-23 in San Jose, Calif.

Burris and his colleagues are not the first to study cartilage deflation. In 1995, a group at Columbia led by Gerard Ateshian used theory to show that continuous knee movement could prevent the deflation process if it occurred faster than the fluid could respond. In 2008, Ateshian’s group demonstrated this phenomenon for the first time using a small sphere articulated against a cartilage plug, showing that interstitial pressure was maintained indefinitely if the contact area moved faster than the diffusive speed of the synovial fluid.

“This study was the first direct evidence that interstitial pressure is a viable mechanism of long term load support and lubrication,” Burris said. “However, it was unclear to us how our joints could prevent deflation given the long periods of time we spend sitting and standing each day without some active input mechanism.” That is, there must be some way for the cartilage to reabsorb the fluid that leaks out when we’re not moving.

Burris had a hunch that the reabsorption process was driven by hydrodynamic pressurization, which occurs whenever the relative motion of two surfaces causes fluid between them to accelerate in the shape of a triangular wedge. For example, when a normal tire travels over water at a high speed, pressure builds until a film forms to lubricate the interface; this is called hydroplaning, and results in a complete loss of frictional control. If the tire were porous, however, the exterior fluid pressure could force fluid back into the tire.

To investigate whether hydrodynamic pressurization could refill deflated cartilage, Burris and A.C. Moore, a Ph.D. student, placed larger-than-average cartilage samples against a glass flat to ensure the presence of the necessary wedge. They found that at slow sliding speeds (less than would occur in a joint at typical walking speeds) cartilage thinning and an increase in friction occurred over time, but as the sliding speed increased toward typical walking speeds, the effect was reversed.

Since their experiment involved stationary contacts — in which contact between glass and cartilage occurs at a single site rather than moving across the entire surface of the cartilage plug — their results couldn’t be explained by migrating contact theory, like the Ateshian group’s. Burris believes that hydrodynamic pressures, which force fluid flow into the cartilage, must have counteracted the fluid lost to exudation.

“We observed a dynamic competition between input and output [of synovial fluid],” Burris said. “We know that cartilage thickness is maintained over decades in the joint and this is the first direct insight into why. It is activity itself that combats the natural deflation process associated with interstitial lubrication.

Future work for Burris and his colleagues includes exploring the implications for osteoarthritis (OA), which is associated with the degradation of cartilage.

http://www.sciencedaily.com/  Science Daily

http://www.sciencedaily.com/releases/2015/10/151021104419.htm  Original web page at Science Daily

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Sea turtles face plastic pollution peril

Study warns that all seven species of marine turtle can ingest or become entangled in discarded plastic debris. A new global review led by the University of Exeter that set out to investigate the hazards of marine plastic pollution has warned that all seven species of marine turtles can ingest or become entangled in the discarded debris that currently litters the oceans.

The research, which was carried out in collaboration with Plymouth Marine Laboratory, North Carolina Wildlife Resources Commission, North Carolina State University, Duke University Marine Lab and James Cook University, is published in the ICES Journal of Marine Science and reveals serious knowledge gaps in the diverse and complex pathways in which plastic pollution can harm marine life.

Joint lead author Sarah Nelms, from the Centre for Ecology and Conservation at the University of Exeter’s Penryn campus said: “I was shocked at how little is known about the impacts of plastic on marine turtles.”

“We know that discarded plastic poses a serious threat to wildlife, but this study shows that more research is urgently needed if we are to understand the scale of the problem.” Annual global plastic production has grown from 1.5 million tonnes to 299 million tonnes in the last 65 years and as a result plastic pollution is increasing, both on land and at sea.

Prof Brendan Godley, who led the team said: “When turtles ingest plastic, they can suffer intestinal blockage that can result in malnutrition which can in turn lead to poor health, reduced growth rates, lower reproductive output and even death.”

“It is sobering to think that almost every piece of plastic that ever entered the sea is still there; breaking down and forming a vast soup of microplastics that could have frightening long-term repercussions.” Entanglement in plastic debris, such as lost fishing gear or discarded packaging, can cause lacerations and increased drag when swimming, which may result in drowning or death by starvation.

Beach litter may also entangle nesting females or trap emerging hatchlings, while potentially affecting turtle nests by altering temperature and changing the permeability of the sediment on nesting beaches. The study demonstrates that urgent action is required to better understand this issue and its effects on marine turtles, so that appropriate and effective mitigation policies can be developed.

http://www.sciencedaily.com/  Science Daily

http://www.sciencedaily.com/releases/2015/10/151009083023.htm  Original web page at Science Daily

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Sex and sea turtles: New study reveals impact of climate change, sea level rise

Marine turtles deposit their eggs in underground nests where they develop unattended and without parental care. Incubation temperature varies with environmental conditions, including rainfall, sun, shade and sand type, and affects developmental rates, hatch and emergence success, and embryonic sex. Although the loggerhead turtle has been around for more than 60 million years, drought, heavy rainfalls and climatic changes are impacting hatchling sex ratios and influencing future reproduction. Because sea turtles don’t have an X or Y chromosome, their sex is defined during development by the incubation environment. Warmer conditions produce females and cooler conditions produce males.

Researchers from Florida Atlantic University have just published the results of a four-year study in the journal Endangered Species Research, on the effects of turtle nest temperatures and sand temperatures and on hatchling seks.

“The shift in our climate is shifting turtles as well, because as the temperature of their nests change so do their reproduction patterns,” said Jeanette Wyneken, Ph.D., professor of biological sciences in FAU’s Charles E. Schmidt College of Science. “The nesting beaches along Florida’s coast are important, because they produce the majority of the loggerhead hatchlings entering the northwestern Atlantic Ocean.”

Loggerhead turtles are already fighting an uphill battle since roughly one in 2,500 to 7,000 sea turtles make it to adulthood. The typical loggerhead produces about 105 eggs per nesting season and would have to nest for more than 10 nesting seasons over the span of 20 to 30 years just to replace herself and possibly one mate. And, if enough males aren’t produced because of climate changes, then this will result in a dire problem for this species.

“If climatic changes continue to force the sex ratio bias of loggerheads to even greater extremes, we are going to lose the diversity of sea turtles as well as their overall ability to reproduce effectively. Sex ratios are already strongly female biased,” said Wyneken. “That’s why it’s critical to understand how environmental factors, specifically temperature and rainfall, influence hatchling sex ratios.”

Wyneken and her team documented rainfall and sand temperature relationships as well as rainfall, nest temperatures and hatchling sex ratios at a loggerhead turtle nesting beach in Boca Raton, located in southeast Florida. Nesting season, which runs from April through October, were sampled across 2010 and 2013. The researchers used temperature dataloggers in the sand at three locations and buried them at three different depths to create temperature profiles of the sand column above the level that would directly influence eggs. The rainfall data were graphed in temporal synchrony with sand temperature for each depth.

Nest temperatures were recorded throughout incubation. Rainfall data collected concurrently with sand temperatures at different depths showed that light rainfall affected only the surface sand; effects of the heaviest rainfall events tended to lower sand temperatures, however, the temperature fluctuations were very small once the moisture reached upper nest depths.

Nest temperature profiles were synchronized with rainfall data from weather services to identify relationships with hatchling sex ratios. The sex of each turtle was verified laparoscopically to provide empirical measures of sex ratios for the nest and the nesting beach.

“The majority of hatchlings in the sampling were female, suggesting that across the four seasons most nest temperatures were not sufficiently cool to produce males,” said Wyneken. “However, in the early portion of the nesting and in wet years, nest temperatures were cooler, and significantly more males hatched.”

http://www.sciencedaily.com/  Science Daily

http://www.sciencedaily.com/releases/2015/10/151015111047.htm  Original web page at Science Daily

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* Mare pedigree influences offspring more than previously thought.

In horse breeding, stallions are usually used to establish a breeding line. In some cases, however, the maternal lineage plays a more important role. Researchers from the Vetmeduni Vienna looked at the gestation length of different mare families and discovered that the length of gestation varies significantly from lineage to lineage. Certain families also produce more female offspring than male foals. The results were published in the journal PLOS One.

Owners of sport and leisure horses are keen on knowing the parentage of their animals. A horse with a good pedigree will often have the desired characteristics in terms of speed, physique and health.

At the Graf Lehndorff Institute for Equine Science, a joint research institution of the Vetmeduni Vienna and the Brandenburg State Stud in Germany, Juliane Kuhl and Christine Aurich investigated the degree to which the maternal lineage influences gestation length and foal characteristics. Together with statistician Kathrin Stock of the agricultural statistics centre VIT in Germany, they analysed the data records for 640 pregnancies in 142 mares.

The broodmares could be assigned to different mare families or lineages. The analysis revealed that the average length of gestation, which in horses ranges between 320 and 360 days, varies from family to family. The gestation length of some maternal lineages was on average 10 days longer than in other families. The fact that gestation length for male foals tends to be generally longer than for female foals is added to the variation from family to family.

“We can still not predict the exact time of birth. The individual fluctuations among individual pregnancies are simply too large. But the information gained from the study can help us to narrow the possible range,” says first author Juliane Kuhl.

“The length of gestation is also of interest for horse breeders. Ideally, a broodmare should give birth to a foal every year. Due to the average gestation which covers approximately 11 months, longer gestation lengths result in a delay in birth of the next foal. Breeders are interested in having foals born at the beginning of the year, as the horses will then compete better against animals born in the same year,” Kuhl explains.

The study also showed that certain maternal lineages produce more female than male foals. The age of the mare also plays a role. Young mares who have their first pregnancy when they are three years old will produce more female foals. Older mares also tend to have more female offspring. For middle-aged mares between four and twelve years the foal sex ratio is balanced.

“These results are important for horse breeders. They could possibly choose their mares depending on the desired sex of a foal,” Kuhl believes.The mechanism behind this phenomenon remains unclear, however.

“We suspect that these effects are due to the differences in mitochondrial DNA. This specific DNA is inherited over the maternal line and influences cell metabolism and placenta function,” says study director Christine Aurich.

“We also know that female embryos are more resilient. As 20 to 30 percent of early pregnancies are lost spontaneously, it is possible that male embryos survive less frequently. This could be a reason for the observed shift in the sex ratio. But it is also possible that embryo survival is influenced by differences in placental function,” Aurich says.

http://www.sciencedaily.com   Science Daily

http://www.sciencedaily.com/releases/2015/10/151016084848.htm  Original web page at Science Daily

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Motion studies: See how they run

Software tools that track how animals move are helping researchers to do everything from diagnosing neurological conditions to illuminating evolution.

Palaeontologist Stephen Gatesy wants to bring extinct creatures to life — virtually speaking. When he pores over the fossilized skeletons of dinosaurs and other long-dead beasts, he tries to imagine how they walked, ran or flew, and how those movements evolved into the gaits of their modern descendents. “I’m a very visual guy,” he says.

But fossils are lifeless and static, and can only tell Gatesy so much. So instead, he relies on XROMM, a software package that he developed with his colleagues at Brown University in Providence, Rhode Island. XROMM (X-ray Reconstruction of Moving Morphology) borrows from the technology of motion capture, in which multiple cameras film a moving object from different angles, and markers on the object are rendered into 3D by a computer program. The difference is that XROMM uses not cameras, but X-ray machines that make videos of bones and joints moving inside live creatures such as pigs, ducks and fish. Understanding how the movements relate to the animals’ bone structure can help palaeontologists to determine what movements would have been possible for fossilized creatures. “It’s a completely different approach” to studying evolution, says Gatesy.

XROMM, released to the public in 2008 as an open-source package, is one of a number of software tools that are expanding what researchers know about how animals and humans walk, crawl and, in some cases, fly (see ‘Movement from inside and out’). That has given the centuries-old science of animal motion relevance to a wide range of fields, from studying biodiversity to designing leg braces, prostheses and other assistive medical devices. “We’re in an intense period of using camera-based and computer-based approaches to expand the questions we can ask about motion,” says Michael Dickinson, a neuroscientist at the California Institute of Technology in Pasadena.

To use and develop effective software, however, scientists must learn how to adapt broad, open-source tools to their own needs — and when to build their own.

Scientists monitoring animal motion use a variety of programs to automate the process.

  • MouseWalker is a gait-tracking system that can help researchers studying the connection between neuroscience and movement. The open-source software package was released in July. Previously, the developers collaborated on FlyWalker, a tool for measuring fly walking.
  • X-ray Reconstruction of Moving Morphology, or XROMM, helps researchers to visualize animals’ bones and joints as 3D moving skeletons. XMA Lab, the latest version of the XROMM software, was released in December 2014.
  • OpenSim is an open-source program that allows researchers to model muscles, bones and the forces that act on them. Some researchers have used it to simulate the outcomes of surgery or to test hypotheses about movement pathologies such as those that affect people with cystic fibrosis or Parkinson’s disease.

The boom in motion-tracking tools has come about in part because of improvements in what researchers can see and measure. The first studies of animal and human motion, dating back to Aristotle, relied on naked-eye observations, anatomy and detailed pictures drawn by hand. In the nineteenth century, the science of biomechanics was boosted by photography — perhaps most famously in a series of images of a galloping horse taken by British photographer Eadweard Muybridge, and published in his Animal Locomotion collection in 1887.

Higher-speed cameras eventually improved what could be captured. But movement studies still needed a person to look through the results frame by frame, laboriously tracing the arc of each step, arm swing or wing flap to extract information about angles and forces. Much of that tedium can now be relieved by computers or other measuring tools. But such tools are often expensive, and even today, many researchers do without them. Gatesy recalls a graduate student’s surprise at the low-tech approach that was used to study gait in rodents a few years ago: “It wasn’t uncommon just to dip their feet into some ink, have them leave some tracks and take measurements from those,” he says.

Lately, however, scientists have been coming up with methods that are much more sophisticated without being too expensive. In July, developmental biologists Richard Mann and César Mendes at Columbia University in New York City and their colleagues published a paper on MouseWalker: a system they have built to automatically analyse changes in a mouse’s gait (C. S. Mendes et al. BMC Biol. 13, 50; 2015). It involves an inexpensive set-up in which a mouse walks on a transparent surface over a high-speed camera that records the animal’s footfalls. An analytical technology called machine vision allows the MouseWalker software to discern details such as the position of each step relative to the mouse’s body.

Mendes says that this information can be used to detect when something goes wrong with gait, as can happen with the onset of neurological illnesses such as Parkinson’s disease. MouseWalker was adapted from FlyWalker, a system that Mendes and his team helped to develop to let neuroscientists track how fruit flies walk after their neurons have been manipulated. Both MouseWalker and FlyWalker are open source: the authors hope that making the software available for free will help to attract users who can add parameters that they had not thought of

The desire to share tools is common to many developers, so motion-tracking software is finding applications in a number of fields — sometimes in unexpected ways. “One of the things we hope for is that people will use what we develop and go in a new direction with it,” says Jen Hicks, an engineer at Stanford University in California, who helps to manage OpenSim — an open-source software package that allows users to model joints, muscles and how they move. OpenSim has more than 20,000 users, and part of Hicks’s job is to organize workshops and tutorials to guide this growing community. The OpenSim community serves as an exemplar of what newer programs such as XROMM or MouseWalker could become. The software models musculoskeletal systems, and researchers have used it to simulate everything from the potential outcomes of surgery to the muscular forces of goats. Since the first version of OpenSim was released in 2007, the package has gone through dozens of upgrades that have added features and improved the algorithms used for calculations. It has been downloaded more than 100,000 times. “It’s amazing how much the community has grown,” says mechanical engineer Katherine Steele of the University of Washington in Seattle, who first began using OpenSim while studying cystic fibrosis as a graduate student at Stanford.

Serving an ever-larger crowd requires careful planning to make the program accessible, says Hicks. Through grants from the US National Institutes of Health, she and her colleagues keep manuals up to date with the new releases. Ensuring that the software can be tailored to a researcher’s particular needs has helped new users to embrace it, she says.

XROMM’s developers are in the middle of building up the infrastructure to make the software accessible to a wider community, for instance setting up a site to host the newest open-source version, XMA Lab, which became available in December 2014. The team has tried to make the latest versions of the software easier for new users. For example, says Brainerd, “There used to be about 20 pieces of information you had to keep track of,” including items such as calibration measurements. “But now it’s all integrated”.

It is important not to make things too easy, says Steele: if the software does too much of the work, there is a risk that the researchers will misunderstand the data that it spits out. However, as an open-source program develops, understanding its architecture can get very complicated. “Sometimes the software can get so big that it becomes black-box-ish. Then it might be better for you to build your own,” she says.

Dickinson agrees, and says that sometimes, modifying open-source tools is not enough. “As science is becoming more quantitative, we’re all working on finer slices of the pie,” he says. “If you only got to use a microscope that someone else built, so to speak, you won’t be able to get as far.”

Regardless of what tools are available, researchers intend to keep expanding the applications of motion tracking. Hicks anticipates seeing more people using the tools to explore neural control and robotics designs. And she expects the software to keep improving. “We’re finding ways to learn from even messier motion data, like from accelerometers in your phone,” she says. “Bringing together more machine learning and biomechanics — that will be the next step.”

Nature 525, 145–146 (03 September 2015) doi:10.1038/525145a

http://www.nature.com/news/index.html Nature

http://www.nature.com/news/motion-studies-see-how-they-run-1.18258 Original web page at Nature

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Dogs, cats, and big-wave surfers: Healthy heart lessons from animals and athletes

Heart rates of big-wave surfers are among the surprises from 30 years of studying exercise physiology in people, wild animals. For over 30 years, Terrie Williams has been studying exercise physiology in wild animals: African lions and wild dogs, dolphins and whales, coyotes and mountain lions, as well as a few human athletes. She has put mountain lions on treadmills and strapped heart-rate monitors onto big-wave surfers at Mavericks.

These studies have given Williams, a professor of ecology and evolutionary biology at UC Santa Cruz, a unique perspective on exercise and health, which she presents in an article titled “The Healthy Heart: Lessons from Nature’s Elite Athletes,” published in the September issue of the journal Physiology.

Of course, you already know the bottom line: Most people should get more exercise. Here are “Six amazing heart findings” to contemplate during your next workout:

  • One of the highest prolonged heart-rate levels ever recorded was for a professional big-wave surfer riding the monstrous swells at Mavericks: more than 180 beats per minute for three hours, with peaks of 200 beats per minute during rides.
  • Dogs and cats are opposites in terms of aerobic capacity and maximum heart rate, and humans are more like dogs, adapted for endurance exercise (chasing down prey), while cats are built for the short bursts of speed used in stalk-and-pounce hunting. This difference is reflected in heart size relative to total body mass (larger hearts in dogs and humans, smaller hearts in cats).
  • The hearts of marathon runners are 10 to 33 percent larger than those of more sedentary people.
  • Heart disease is exceedingly rare in wild animals, but it is the leading cause of death in humans worldwide. There are many plausible explanations for this, but one factor stands out above all others: the difference in daily activity levels. “We just don’t ask our hearts to do very much on a daily basis,” Williams said.
  • The mammalian dive response, automatically triggered by cold water contacting the face, involves an immediate slowing of heart rate and constriction of peripheral blood vessels to maximize blood and oxygen in the core. The mammalian exercise response has the opposite effect, increasing heart rate and metabolism. Thus, marine mammals chasing prey at depth have to balance opposing cardiovascular demands, and Williams found they can experience cardiac arrhythmias during dives.
  • Heart rate can be consciously controlled, and not just by meditating yogis. A California sea lion was trained to lower its heart rate on command while sitting out of water.

For Williams, the main reason to study exercise physiology in animals is to better understand how much energy they have to expend to live in their environments, and how they might be affected by environmental changes and human activities. Williams is also an athlete herself and has competed in a number of triathlons, so she has always been interested in what humans can learn from nature’s elite athletes. “The big difference between wild animals and humans is that they’re out there exercising for hours at a time, from the day they’re born to the day they die,” she said. “My own activity level is pretty pathetic relative to even a lion, and they’re not the most active animals. I take a lot out of these lessons from animals in terms of how much and what kinds of exercise I try to do. Mixing it up with both sprints and low-intensity exercise is the secret.”

Looking at heart rates in humans, Williams has been struck by the influence of psychological factors, as seen most dramatically in the big-wave surfers. Their high prolonged heart rates (90 percent of maximum based on treadmill tests) are induced by adrenaline, not exercise. “Just sitting on the beach before they entered the water caused the heart rates of surfers to reach almost 180 beats per minute,” Williams said.

The same phenomenon is seen in other thrill-seeking sports. Formula race car drivers and motocross racers have also been found to maintain heart rates at 90 percent of maximum for prolonged periods, though not for as long as the surfers. “The psychological component has tended to be overlooked, but you can really see it in surfers. People do these thrill-seeking sports for the adrenaline rush, and that affects the heart,” Williams said.

Is it healthy? “They’re in amazing shape overall, and I’ve never heard of any problems from a prolonged high heart rate unless there’s a pre-existing condition. But they can be exhausted for a week after battling the big waves,” she said.

Unlike human surfers, dolphins’ heart rates go down when they’re riding waves. When Williams was trying to measure heart rates of swimming dolphins, she couldn’t keep them from riding her boat’s bow wave. “They’re not doing it for the thrill; they’re just saving energy by taking the easy way out,” she said.

The discovery of cardiac arrhythmias in deep-diving marine mammals got Williams thinking about the fact that the swimming segment of triathlons accounts for over 90 percent of race day deaths, especially in cold water venues. The combination of high heart rates at the start of the race (Williams said she knows from experience that the adrenaline is flowing as racers charge into the water) and sudden immersion in cold water is an extreme challenge for the heart. It can be overwhelming for people with pre-existing cardiac conditions, she said. In response, the USA Triathlon organization issued new water temperature guidelines in 2013 for sanctioned events.

http://www.sciencedaily.com/  Science Daily

http://www.sciencedaily.com/releases/2015/09/150901140755.htm  Original web page at Science Daily

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Gut microbes affect circadian rhythms and metabolism in mice

By now, the old saw, “You are what you eat,” has been well-used in describing the microbiome. However axiomatic that phrase may be, a new study has also found that who and when that consumption is done can affect microbiome make-up. Changes in the abundance of mouse gut bacteria, over a 24-hour cycle, particularly in females, is tied to rhythms in the internal clock, according to work published online in the Early Edition of the Proceedings of the National Academy of Science, by researchers from the Perelman School of Medicine at the University of Pennsylvania.

In mammals, most physiological, metabolic, and behavioral processes follow a daily, or circadian, rhythm, adapting to changing light in the environment. Recent studies of the mouse microbiome have found that the microbes that live in mammals have their own circadian behavior, which has been shown to be linked to host feeding time. However, how this all ties together has not been fully clarified.

Doctoral student Xue Liang, working with the labs of authors Garret A. FitzGerald, MD, FRS, chair of the department of Systems Pharmacology and Translational Therapeutics, and Frederic Bushman, PhD, chair of the department of Microbiology, analyzed circadian rhythms in abundance and type of microbiota in the gut and feces of mice using genetic sequencing. They found that the absolute abundance of Bacteroidetes, a large group of rod-shaped bacteria common in the gut and skin of animals, and relative species make-up of the microbiome, changed over a 24-hour cycle. What’s more, this rhythmicity was more pronounced in female mice.

Normally, during the daytime, when the mice are resting and consuming less food, Bacteroidetes are predominant, reaching the highest abundance toward the end of the light phase. The influence of food may reflect the varying nutrient availability to bacteria. Components in host diet and mucus in the intestines provide carbon sources to the bacteria. Several strains of Bacteroidetes have evolved to use host mucous carbon when dietary carbon is in short supply, which may partially explain the blooming of Bacteroidetes in the resting phase.

But how are internal clock and sex involved in setting up these patterns? When the Penn team disrupted the clock gene Bmal, any trace of a 24-hour cycle in the composition of fecal microbiota in both male and female mice was eliminated. Bmal deletion also induced changes in bacterial abundances in feces, with differential effects based on sex. Although microbiota in both males and females exhibited circadian rhythmicity, females showed more significant oscillation than males. However, the effect of host sex is secondary to the host circadian clock in shaping the rhythmicity, because Bmal deletion abolished the rhythmicity irrespective of seks.

“Although host behavior, such as time of feeding, is recognized to play a large role in explaining these intertwined cycles, we show that sex interacts with the circadian clock, and these factors collectively shape the circadian rhythmicity and composition of the fecal microbes in mice,” says first author Liang. “Our findings suggest the need to consider circadian factors and host gender in the design of microbiome studies and highlight the importance of analyzing absolute abundance in understanding the microbiome and its influence on physiology, and possibly inflammatory bowel disease.”

http://www.sciencedaily.com/  Science Daily

http://www.sciencedaily.com/releases/2015/08/150804103636.htm  Original web page at Science Daily