Ancient, giant marine animals used bizarre facial appendages to filter food from the ocean, according to new fossils discovered in northern Greenland. The new study, led by the University of Bristol and published today in Nature, describes how the strange species, called Tamisiocaris, used these huge, specialized appendages to filter plankton, similar to the way modern blue whales feed today.The animals lived 520 million years ago during the Early Cambrian, a period known as the ‘Cambrian Explosion’ in which all the major animal groups and complex ecosystems suddenly appeared. Tamisiocaris belongs to a group of animals called anomalocarids, a type of early arthropod that included the largest and some of the most iconic animals of the Cambrian period. They swam using flaps down either side of the body and had large appendages in front of their mouths that they most likely used to capture larger prey, such as trilobites.However, the newly discovered fossils show that those predators also evolved into suspension feeders, their grasping appendages morphing into a filtering apparatus that could be swept like a net through the water, trapping small crustaceans and other organisms as small as half a millimetre in size.The evolutionary trend that led from large, apex predators to gentle, suspension-feeding giants during the highly productive Cambrian period is one that has also taken place several other times throughout Earth’s history, according to lead author Dr Jakob Vinther, a lecturer in macroevolution at the University of Bristol.Dr Vinther said: “These primitive arthropods were, ecologically speaking, the sharks and whales of the Cambrian era. In both sharks and whales, some species evolved into suspension feeders and became gigantic, slow-moving animals that in turn fed on the smallest animals in the water.”In order to fully understand how the Tamisiocaris might have fed, the researchers created a 3D computer animation of the feeding appendage to explore the range of movements it could have made.”Tamisiocaris would have been a sweep net feeder, collecting particles in the fine mesh formed when it curled its appendage up against its mouth,” said Dr Martin Stein of the University of Copenhagen, who created the computer animation. “This is a rare instance when you can actually say something concrete about the feeding ecology of these types of ancient creatures with some confidence.”The discovery also helps highlight just how productive the Cambrian period was, showing how vastly different species of anomalocaridids evolved at that time, and provides further insight into the ecosystems that existed hundreds of millions of years ago.”The fact that large, free-swimming suspension feeders roamed the oceans tells us a lot about the ecosystem,” Dr Vinther said. “Feeding on the smallest particles by filtering them out of the water while actively swimming around requires a lot of energy — and therefore lots of food.”Tamisiocaris is one of many recent discoveries of remarkably diverse anomalocarids found in rocks aged 520 to 480 million years old. “We once thought that anomalocarids were a weird, failed experiment,” said co-author Dr Nicholas Longrich at the University of Bath. “Now we’re finding that they pulled off a major evolutionary explosion, doing everything from acting as top predators to feeding on tiny plankton.”The Tamisiocaris fossils were discovered during a series of recent expeditions led by co-author David Harper, a professor at Durham University. “The expeditions have unearthed a real treasure trove of new fossils in one of the remotest parts of the planet, and there are many new fossil animals still waiting to be described,” he said. …Read more
With one in seven humans undernourished, and with the challenges of population growth and climate change, the need for efficient food production has never been greater. Eight strategies to cut the environmental and economic costs of keeping livestock, such as cows, goats and sheep, while boosting the quantity and quality of the food produced have been outlined by an international team of scientists.The strategies to make ruminant — cud-chewing — livestock a more sustainable part of the food supply, led by academics at the University of Bristol’s School of Veterinary Sciences, are outlined in a Comment piece in Nature this week.The eight strategies include:Feed animals less human food. Livestock consume an estimated one-third or more of the world’s cereal grain, which some advocate would be better used to feed people directly. Some of this could indeed be avoided by capitalising on ruminants’ ability to digest food that humans cannot eat, such as hay, silage and high-fibre crop residues. Raise regionally appropriate animals. Working to boost yields from local breeds makes more sense in the long term than importing poorly adapted breeds that are successful elsewhere. European and North American Holstein dairy cows can produce 30 litres of milk a day. Thousands of these animals have been exported to Asia and Africa in an attempt to alleviate malnutrition. But exposed to hot climates, tropical diseases and sub-optimal housing, the cows produce much less milk, and the costs of feed and husbandry far exceed those of native breeds. Farmers, therefore, should be encouraged to keep and improve livestock adapted to local conditions. …Read more
Patients are more likely to raise a health problem with a doctor they’ve seen over time and have built-up a relationship with, new research has revealed. The insight comes as an increasing number of patients struggle to see the same GP.Researchers from the University of Bristol will share their findings with health practitioners and researchers at the South West Society for Academic Primary Care (SW SAPC) meeting today.Seeing the same GP is thought to be important in ensuring quality of patient care, as the doctor will have better knowledge of the patient’s history, medications, and health-related behaviors and attitudes.However, a quarter of patients find it difficult to see the doctor of their choice most of the time due to a combination of factors. Namely, a reduction in doctors’ working hours, an increase in part-time working, a focus on access and rapid appointments in the 2004 GP contract, and organisational changes in out-of-hours care.Previous studies have quantified the numbers and types of problems that are raised in GP consultations, but there is little evidence about the effect of increasing depth of patient-doctor relationships on the content of these interactions.To shed light on this, researchers collected data from 22 practices in the Bristol area, recording consultations between 190 patients and 30 GPs.Researchers then looked at whether consultation length and the number of problems and issues raised were affected by patient-doctor continuity.Analysis showed that almost a third of patients had a ‘deep’ relationship with their GP, which in turn encouraged them to raise 0.5 more problems (a topic requiring a GP to make a decision or diagnosis) and 0.9 more issues (the number of topics raised within each problem, such as symptoms) during each consultation.This may mean many more problems and issues are addressed over the course of several visits.Dr Matthew Ridd, from Bristol University’s School of Social and Community Medicine, was part of the research team and said: “Participants mostly reported a strong relationship with their GP, built-up over time. There was evidence that patients raised more problems and issues with GPs that they felt they had a deep relationship with.”This could be because patients feel more comfortable raising additional issues with a GP they feel they know well, or because more issues can be addressed within the time available as the GP knows the patient and their medical history.”This research study is the first of its kind to show how seeing the same doctor can positively affect consultations.”The study also found that the type of problem or issue raised was not related to the depth of the relationship between the patient and their doctor, except that behavioural problems or issues were less likely to be raised when a deep relationship existed.Story Source:The above story is based on materials provided by University of Bristol. Note: Materials may be edited for content and length.Read more
The change by our ancestors from hunter-gathers to farmers is one of the most intensively researched aspects of archaeology. Now a large-scale investigation of British archaeological sites dating from around 4,600 BC to 1,400 AD has examined millions of fragments of bone and analysed over 1,000 cooking pots.The team, led by Professor Richard Evershed of the University of Bristol’s School of Chemistry, developed new techniques in an effort to identify fish oils in the pots. Remarkably, they showed that more than 99 per cent of the earliest farmer’s cooking pots lacked sea food residues.Other clues to ancient diets lie within human bones themselves, explored by the Cardiff group led by Dr Jacqui Mulville. The sea passes on a unique chemical signature to the skeletons of those eating seafood; while the early fisher folk possessed this signature it was lacking in the later farmers.Lead author of the study, Dr Lucy Cramp said: “The absence of lipid residues of marine foods in hundreds of cooking pots is really significant. It certainly stacks up with the skeletal isotope evidence to provide a clear picture that seafood was of little importance in the diets of the Neolithic farmers of the region.”Returning to the pots, the Bristol team used a compound-specific carbon isotope technique they have developed to identify the actual fats preserved in the cooking pots, showing that dairy products dominated the menu right across Britain and Ireland as soon as cattle and sheep arrived.The ability to milk animals was a revolution in food production as, for the first time humans did not have to kill animals to obtain food. As every farmer knows, milking stock requires a high level of skill and knowledge.In view of this, team member, Alison Sheridan from the National Museum of Scotland concludes that: “The use of cattle for dairy products from the earliest Neolithic confirms the view that farming was introduced by experienced immigrants.”Viewed together the findings show that Early British hunters feasted on venison and wild boar and ate large quantities of sea food, including seals and shellfish. With the introduction of domestic animals some 6,000 years ago they quickly gave up wild foods and fishing was largely abandoned, and people adopted a new diet based around dairying.Dr Cramp continued: “Amazingly, it was another 4,000 years before sea food remains appeared in pots again, during the Iron Age, and it was only with the arrival of the Vikings that fish became a significant part of our diet.”Dr Mulville said: “Whilst we like to think of ourselves as a nation of fish eaters, with fish and chips as our national dish, it seems that early British farmers preferred beef, mutton and milk.”Why people changed so abruptly from a seafood to farming diet remains a mystery. Professor Evershed said: “Since such a clear transition is not seen in the Baltic region, perhaps the hazardous North Atlantic waters were simply too difficult to fish effectively until new technologies arrived, making dairying the only sustainable option.”Story Source:The above story is based on materials provided by University of Bristol. Note: Materials may be edited for content and length.Read more
Sep. 12, 2013 — Previously believed to be only human-made, a natural example of a functioning gear mechanism has been discovered in a common insect — showing that evolution developed interlocking cogs long before we did.The juvenile Issus – a plant-hopping insect found in gardens across Europe — has hind-leg joints with curved cog-like strips of opposing ‘teeth’ that intermesh, rotating like mechanical gears to synchronise the animal’s legs when it launches into a jump.The finding demonstrates that gear mechanisms previously thought to be solely human-made have an evolutionary precedent. Scientists say this is the “first observation of mechanical gearing in a biological structure.”Through a combination of anatomical analysis and high-speed video capture of normal Issus movements, scientists from the University of Cambridge have been able to reveal these functioning natural gears for the first time. The findings are reported in the latest issue of the journal Science.The gears in the Issus hind-leg bear remarkable engineering resemblance to those found on every bicycle and inside every car gear-box. Each gear tooth has a rounded corner at the point it connects to the gear strip; a feature identical to human-made gears such as bike gears — essentially a shock-absorbing mechanism to stop teeth from shearing off.The gear teeth on the opposing hind-legs lock together like those in a car gear-box, ensuring almost complete synchronicity in leg movement — the legs always move within 30 ‘microseconds’ of each other, with one microsecond equal to a millionth of a second.This is critical for the powerful jumps that are this insect’s primary mode of transport, as even miniscule discrepancies in synchronisation between the velocities of its legs at the point of propulsion would result in “yaw rotation” — causing the Issus to spin hopelessly out of control.”This precise synchronisation would be impossible to achieve through a nervous system, as neural impulses would take far too long for the extraordinarily tight coordination required,” said lead author Professor Malcolm Burrows, from Cambridge’s Department of Zoology.”By developing mechanical gears, the Issus can just send nerve signals to its muscles to produce roughly the same amount of force — then if one leg starts to propel the jump the gears will interlock, creating absolute synchronicity.”In Issus, the skeleton is used to solve a complex problem that the brain and nervous system can’t,” said Burrows. “This emphasises the importance of considering the properties of the skeleton in how movement is produced.””We usually think of gears as something that we see in human designed machinery, but we’ve found that that is only because we didn’t look hard enough,” added co-author Gregory Sutton, now at the University of Bristol.”These gears are not designed; they are evolved — representing high speed and precision machinery evolved for synchronisation in the animal world.”Interestingly, the mechanistic gears are only found in the insect’s juvenile — or ‘nymph’ — stages, and are lost in the final transition to adulthood. These transitions, called ‘molts’, are when animals cast off rigid skin at key points in their development in order to grow.It’s not yet known why the Issus loses its hind-leg gears on reaching adulthood. The scientists point out that a problem with any gear system is that if one tooth on the gear breaks, the effectiveness of the whole mechanism is damaged. While gear-teeth breakage in nymphs could be repaired in the next molt, any damage in adulthood remains permanent.It may also be down to the larger size of adults and consequently their ‘trochantera’ — the insect equivalent of the femur or thigh bones. The bigger adult trochantera might allow them to can create enough friction to power the enormous leaps from leaf to leaf without the need for intermeshing gear teeth to drive it, say the scientists.Each gear strip in the juvenile Issus was around 400 micrometres long and had between 10 to 12 teeth, with both sides of the gear in each leg containing the same number — giving a gearing ratio of 1:1.Unlike human-made gears, each gear tooth is asymmetrical and curved towards the point where the cogs interlock — as human-made gears need a symmetric shape to work in both rotational directions, whereas the Issus gears are only powering one way to launch the animal forward.While there are examples of apparently ornamental cogs in the animal kingdom — such as on the shell of the cog wheel turtle or the back of the wheel bug — gears with a functional role either remain elusive or have been rendered defunct by evolution.The Issus is the first example of a natural cog mechanism with an observable function, say the scientists.Read more
Sep. 10, 2013 — New research has revealed the hidden past of crocodiles, showing for the first time how these fierce reptiles evolved and survived in a dinosaur dominated world.While most modern crocodiles live in freshwater habitats and feed on mammals and fish, their ancient relatives were extremely diverse — with some built for running around like dogs on land and others adapting to life in the open ocean, imitating the feeding behaviour of today’s killer whales.Research published today [11 September] in the journal Proceedings of the Royal Society B shows, for the first time, how the jaws of ancient crocodiles evolved to enable these animals to survive in vastly different environments, all whilst living alongside the dinosaurs 235 to 65 million years ago.The study was conducted by Tom Stubbs and Dr Emily Rayfield from the University of Bristol, together with Dr Stephanie Pierce from The Royal Veterinary College and Dr Phil Anderson from Duke University.Tom Stubbs, who led the research at the University of Bristol, said: “The ancestors of today’s crocodiles have a fascinating history that is relatively unknown compared to their dinosaur counterparts. They were very different creatures to the ones we are familiar with today, much more diverse and, as this research shows, their ability to adapt was quite remarkable.”Their evolution and anatomical variation during the Mesozoic Era was exceptional. They evolved lifestyles and feeding ecologies unlike anything seen today.”The research team examined variation in the morphology (shape) and biomechanics (function) of the lower jaws in over 100 ancient crocodiles, using a unique combination of numerical methods.Dr Stephanie Pierce, from The Royal Veterinary College, said: “We were curious how extinction events and adaptations to extreme environments during the Mesozoic — a period covering over 170 million years — impacted the feeding systems of ancient crocodiles and to do this we focused our efforts on the main food processing bone, the lower jaw.”By analysing variation in the lower jaw, the researchers provide novel insights into how the feeding systems of ancient crocodiles evolved as the group recovered from the devastating end-Triassic extinction event and subsequently responded to the distribution of ecological resources, such as habitat and foodstuff.For the first time, the research has shown that, following the end-Triassic extinction, ancient crocodiles invaded the Jurassic seas and evolved jaws built primarily for hydrodynamic efficiency to capture agile prey, such as fish. However, only a small range of elongate lower jaw shapes were suitable in Jurassic marine environments.The study has also revealed that variation peaked again in the Cretaceous, where ancient crocodiles evolved a great variety of lower jaw shapes, as they adapted to a diverse range of feeding ecologies and terrestrial environments, alongside the dinosaurs.Surprisingly, the lower jaws of Cretaceous crocodiles did not have a great amount of biomechanical variation and, instead, the fossil record points towards novel adaptations in other areas of their anatomy, such as armadillo-like body armour.Dr Pierce added: “Our results show that the ability to exploit a variety of different food resources and habitats, by evolving many different jaw shapes, was crucial to recovering from the end-Triassic extinction and most likely contributed to the success of Mesozoic crocodiles living in the shadow of the dinosaurs.”This exceptional variation has never before been explored numerically, with no studies ever having incorporated such a wide range of crocodiles over such a long time period.Read more
Sep. 3, 2013 — Removing one of the tiniest organs in the body has shown to provide effective treatment for high blood pressure. The discovery, made by University of Bristol researchers and published in Nature Communications, could revolutionise treatment of the world’s biggest silent killer.The carotid body — a small nodule (no larger than a rice grain) found on the side of each carotid artery — appears to be a major culprit in the development and regulation of high blood pressure.Researchers, led by Professor Julian Paton, found that by removing the carotid body connection to the brain in rodents with high blood pressure, blood pressure fell and remained low.Professor Paton, from Bristol’s School of Physiology and Pharmacology, said: “We knew that these tiny organs behaved differently in conditions of hypertension but had absolutely no idea that they contributed so massively to the generation of high blood pressure; this is really most exciting.”Normally, the carotid body acts to regulate the amount of oxygen and carbon-dioxide in the blood. They are stimulated when oxygen levels fall in your blood as occurs when you hold your breath. This causes a dramatic increase in breathing and blood pressure until blood oxygen levels are restored. This response comes about through a nervous connection between the carotid body and the brain.Professor Paton commented: “Despite its small size the carotid body has the highest blood flow of any organ in the body. Its influence on blood pressure likely reflects the priority of protecting the brain with enough blood flow.”The team’s work on carotid body research started in the late 1990’s and their recent discovery has since led to a human clinical trial at the Bristol Heart Institute of which the results are expected at the end of the year.Professor Paton added: “This is an extremely proud moment for my research team as it is rare that this type of research can so quickly fuel a human clinical trial. I am delighted that Bristol was chosen as a site for this important trial.”The work was funded by the British Heart Foundation, Cibiem, New York and the National Institutes of Health.Read more
Aug. 13, 2013 — As growing numbers of species in the modern world face extinction because of global climate change, habitat destruction, and over-exploitation, scientists have turned to the fossil record to understand how mass extinctions in the past proceeded, and how species and ecosystems recovered in the aftermath of such events.Much work so far suggests that the survivors of mass extinctions often are presented with new ecological opportunities because the loss of many species in their communities allows them to evolve new lifestyles and new anatomical features as they fill the roles vacated by the victims.However, it turns out that not all survivors respond in the same way, and some may not be able to exploit fully the new opportunities arising after a mass extinction. A team of researchers from the University of Lincoln, the Field Museum of Natural History in Chicago, the Museum für Naturkunde in Berlin, and the University of Bristol examined how a group of ancient relatives of mammals called anomodonts responded in the aftermath of the largest mass extinction in Earth history. Their work, published this week in Proceedings of the Royal Society B and titled “Decoupling of morphological disparity and taxic diversity during the adaptive radiation of anomodont therapsids,” shows that anomodonts remained anatomically conservative even as the number of species rebounded during the recovery.The mass extinction at the end of the Permian Period, about 252 million years ago, had profound effects on organisms on land and in the sea, with as many as 90% of marine organisms and 70% of terrestrial species becoming extinct. “Groups of organisms that survive such a mass extinction are said to have passed through an evolutionary bottleneck analogous to the genetic bottleneck that may occur in a population if many of its members die off,” said Dr. Marcello Ruta of the University of Lincoln, the lead author of the study. “At the population level, a genetic bottleneck sometimes allows the population to move to a new evolutionary trajectory, but other times it constrains the future evolution of the population.””Near the end of the Permian, a large number of anomodont species existed that displayed a wide range of body sizes and ecological adaptations, including terrestrial plant eaters, amphibious hippo-like species, specialized burrowers, and even tree-dwelling forms,” said Dr. Kenneth Angielczyk. “The most successful group of anomodonts had canine-like tusks in their upper jaws and turtle-like beaks, and they were the most important terrestrial herbivores of their time.””The number of anomodont species increased during the Permian, sharply dropped during the end-Permian extinction event, and then rebounded in the Middle Triassic Period (about 240 million years ago) before the final extinction of the group at the end of the Triassic,” said Professor Jörg Fröbisch. “However, the variety of different anatomical features found in anomodonts, i.e. …Read more
June 28, 2013 — Tracking the growth of dinosaurs and how they changed as they grew is difficult. Using a combination of biomechanical analysis and bone histology, palaeontologists from Beijing, Bristol, and Bonn have shown how one of the best-known dinosaurs switched from four feet to two as it grew.Psittacosaurus, the ‘parrot dinosaur’ is known from more than 1000 specimens from the Cretaceous, 100 million years ago, of China and other parts of east Asia. As part of his PhD thesis at the University of Bristol, Qi Zhao, now on the staff of the Institute for Vertebrate Paleontology in Beijing, carried out the intricate study on bones of babies, juveniles and adults.Dr Zhao said: “Some of the bones from baby Psittacosaurus were only a few millimetres across, so I had to handle them extremely carefully to be able to make useful bone sections. I also had to be sure to cause as little damage to these valuable specimens as possible.”With special permission from the Beijing Institute, Zhao sectioned two arm and two leg bones from 16 individual dinosaurs, ranging in age from less than one year to 10 years old, or fully-grown. He did the intricate sectioning work in a special palaeohistology laboratory in Bonn, Germany,The one-year-olds had long arms and short legs, and scuttled about on all fours soon after hatching. The bone sections showed that the arm bones were growing fastest when the animals were ages one to three years. Then, from four to six years, arm growth slowed down, and the leg bones showed a massive growth spurt, meaning they ended up twice as long as the arms, necessary for an animal that stood up on its hind legs as an adult.Professor Xing Xu of the Beijing Institute, one of Dr Zhao’s thesis supervisors, said: “This remarkable study, the first of its kind, shows how much information is locked in the bones of dinosaurs. We are delighted the study worked so well, and see many ways to use the new methods to understand even more about the astonishing lives of the dinosaurs.”Professor Mike Benton of the University of Bristol, Dr Zhao’s other PhD supervisor, said: “These kinds of studies can also throw light on the evolution of a dinosaur like Psittacosaurus. Having four-legged babies and juveniles suggests that at some time in their ancestry, both juveniles and adults were also four-legged, and Psittacosaurus and dinosaurs in general became secondarily bipedal.”The paper is published in Nature Communications.Read more
June 20, 2013 — One of the largest clinical trials done in infants with congenital (present at birth) heart diseases, published in the New England Journal of Medicine, shows that the increasingly common practice of using the drug clopidogrel (Plavix®) to reduce shunt-related blood flow issues is not effective in the dose studied.”Once again, pediatric-specific research shows that newborns and infants are not little adults,” said David Wessel, MD, Chief Medical Officer, Children’s National Medical Center, and lead author on the international study published in the June 20, 2013 issue of the New England Journal of Medicine. “The take away message for pediatric cardiac care providers is to reconsider use of Plavix® in certain cases. In pediatric medicine, the assumption is that smaller doses of a drug that works in adults will work in infants, but our study shows that this is not true for these young patients. For the parents of these fragile newborns, it is important to understand that research informs best practices, and they need to be informed advocates for their children.”The objective of this international trial, which included more than 900 patients seen across 134 centers in 33 countries, was to evaluate the efficacy of Plavix® compared with placebo for the reduction of all-cause mortality and shunt-related morbidity in neonates and infants with cyanotic congenital heart disease palliated with systemic-to-pulmonary artery shunts. Many forms of congenital heart disease can be repaired in early infancy, and pulmonary blood flow with shunts is an important consideration during initial treatment that may include reconstructive heart surgery for defects in heart ventricles.As the authors note, effective prevention for thrombosis (blood clots) in neonates and infants with these heart conditions had not been previously tested, although aspirin treatment was associated with significantly lower risk of mortality and shunt thrombosis in a separate registry developed before this trial. Preventive treatment in adult patients who develop clots in coronary arteries often combines aspirin and Plavix®. As happens with many drugs approved for use in adults, Plavix® use is spreading into pediatric practice without sound evidence, according to study authors. In fact, they continue, use of this drug has increased 15-fold from 2001 to 2009 in children’s hospitals in the US.This study showed no benefit from adding Plavix® to current treatment, which often includes aspirin. As noted in the study, the use of Plavix® to address thrombosis in newborns and infants being palliated with systemic-to-pulmonary artery shunts does not reduce all-cause mortality or shunt-related morbidity.Further analysis (not part of the original trial design) supports the notion that aspirin alone may be effective at reducing the risk of clot formation in these infants. The study authors point out that the trial suggests that switching from aspirin alone to Plavix® alone at the dose studied is not a good idea.”This is a good illustration of the successful collaboration between industry and academia to conduct clinical research in children under the written request process of FDA’s Best Pharmaceuticals for Children Act (BPCA), noted Edward Connor, MD, MBE, Director of Innovation Development at Children’s National and internationally recognized expert on drug development. …Read more
June 13, 2013 — A new study of the genetic origins of dyslexia and other learning disabilities could allow for earlier diagnoses and more successful interventions, according to researchers at Yale School of Medicine. Many students now are not diagnosed until high school, at which point treatments are less effective.The study is published online and in the July print issue of the American Journal of Human Genetics. Senior author Dr. Jeffrey R. Gruen, professor of pediatrics, genetics, and investigative medicine at Yale, and colleagues analyzed data from more than 10,000 children born in 1991-1992 who were part of the Avon Longitudinal Study of Parents and Children (ALSPAC) conducted by investigators at the University of Bristol in the United Kingdom.Gruen and his team used the ALSPAC data to unravel the genetic components of reading and verbal language. In the process, they identified genetic variants that can predispose children to dyslexia and language impairment, increasing the likelihood of earlier diagnosis and more effective interventions.Dyslexia and language impairment are common learning disabilities that make reading and verbal language skills difficult. Both disorders have a substantial genetic component, but despite years of study, determining the root cause had been difficult.In previous studies, Gruen and his team found that dopamine-related genes ANKK1 and DRD2 are involved in language processing. In further non-genetic studies, they found that prenatal exposure to nicotine has a strong negative affect on both reading and language processing. They had also previously found that a gene called DCDC2 was linked to dyslexia.In this new study, Gruen and colleagues looked deeper within the DCDC2 gene to pinpoint the specific parts of the gene that are responsible for dyslexia and language impairment. They found that some variants of a gene regulator called READ1 (regulatory element associated with dyslexia1) within the DCDC2 gene are associated with problems in reading performance while other variants are strongly associated with problems in verbal language performance.Gruen said these variants interact with a second dyslexia risk gene called KIAA0319. …Read more
May 5, 2013 — Globalisation, with its ever increasing demand for cargo transport, has inadvertently opened the flood gates for a new, silent invasion. New research has mapped the most detailed forecast to date for importing potentially harmful invasive species with the ballast water of cargo ships.
Scientists from the Universities of Bristol, UK, and Oldenburg, Germany, have examined ship traffic data and biological records to assess the risk of future invasions. Their research is published in the latest issue of Ecology Letters.
Animals and plants can hitch a ride on cargo ships, hiding as stowaways in the ballast tanks or clinging to the ship’s hull. Upon arrival in a new port, alien species can then wreak havoc in formerly pristine waters. These so-called invasive species can drive native species to extinction, modify whole ecosystems and impact human economy.
Some regions, such as the San Francisco Bay or Chesapeake Bay, have even reported several new exotic species per year. The knock-on effects to fishermen, farmers, tourism and industry create billions of US dollars in damage every year. Conservationists and ship engineers are now trying to prevent the next big invasion. But without knowing when and where it may occur, their possibilities remain limited.
As part of the research project, funded by the Volkswagen Foundation, the team obtained detailed logs of nearly three million ship voyages in 2007 and 2008. Depending on the particular route travelled by each ship, the researchers estimated the probability that a species survives the journey and establishes a population in subsequent ports of call. Although this probability is tiny for any single voyage, the numbers quickly add up because modern cargo traffic volumes are enormous.
Professor Bernd Blasius from the University of Oldenburg and one of the researchers involved in the study, said: “Our model combines information such as shipping routes, ship sizes, temperatures and biogeography to come up with local forecasts of invasion probabilities.”
The final tally reveals the hotspots of bioinvasion. Large Asian ports such as Singapore and Hong Kong but also US ports like New York and Long Beach are among the sites of highest invasion probability. These waterways are notoriously busy, but, traffic is not the only important factor.
The North Sea, for example, does not rank among the top endangered regions despite intense shipping. Temperatures here are lower, making it more difficult for alien species to survive. However, arrivals from the other side of the Atlantic pose a serious threat to the North Sea. Most invaders are predicted to originate from the North American east coast.
Hanno Seebens from the University of Oldenburg said: “We also compared our model results to field data. And, indeed, most of the alien species actually do originate from there.”
As severe as the risk of future invasions may be, the study also contains a hopeful message. If ship engineers could prevent at least some potential invaders from getting on board, the total invasion risk could be substantially mitigated.
By successfully removing a species from 25 per cent of the ballast tanks arriving at each port (eg with filters, chemicals or radiation), the overall invasion probability decreases by 56 per cent. The reduction is so disproportionately large because the effect of ballast water treatment multiplies at successive stopovers.
Bioinvasion is, as the researchers admit, a complex process, and records of past invasions are far from comprehensive. Facing these uncertainties, they simulated various different scenarios. Interestingly, the key results are comparable for different models, predicting the same hotspots and global highways of bioinvasion. The traffic on the main shipping routes plays the greatest role for the calculation.
Dr Michael Gastner, Lecturer in Engineering Mathematics at the University of Bristol, added: “Ship movements in the past few years are well documented, but there are many unknowns about future trade routes.”
For example, the future of the world economy remains uncertain, and Arctic passages may become navigable as a consequence of global warming. Future simulations will also have to take into account which engineering solutions for ballast water treatment will eventually be adopted by port authorities.Read more
May 14, 2013 — Limiting the amount of warming experienced by the world’s oceans in the future could buy some time for tropical coral reefs, say researchers from the University of Bristol.
The study, published by the journal Geophysical Research Letters, used computer models to investigate how shallow-water tropical coral reef habitats may respond to climate change over the coming decades.
Elena Couce and colleagues found that restricting greenhouse warming to three watts per square metre (equivalent to just 50-100 parts per million carbon dioxide, or approximately half again the increase since the Industrial Revolution) is needed in order to avoid large-scale reductions in reef habitat occurring in the future.
Shallow-water tropical coral reefs are amongst the most productive and diverse ecosystems on the planet. They are currently in decline due to increasing frequency of bleaching events, linked to rising temperatures and fossil fuel emissions.
Elena Couce said: “If sea surface temperatures continue to rise, our models predict a large habitat collapse in the tropical western Pacific which would affect some of the most biodiverse coral reefs in the world. To protect shallow-water tropical coral reefs, the warming experienced by the world’s oceans needs to be limited.”
The researchers modelled whether artificial means of limiting global temperatures — known as solar radiation ‘geoengineering’ — could help. Their results suggest that if geoengineering could be successfully deployed then the decline of suitable habitats for tropical coral reefs could be slowed. They found, however, that over-engineering the climate could actually be detrimental as tropical corals do not favour overly-cool conditions. Solar radiation geoengineering also leaves unchecked a carbon dioxide problem known as ‘ocean acidification’.
Elena Couce said: “The use of geoengineering technologies cannot safeguard coral habitat long term because ocean acidification will continue unabated. Decreasing the amount of carbon dioxide in the atmosphere is the only way to address reef decline caused by ocean acidification.”
Dr Erica Hendy, one of the co-authors, added: “This is the first attempt to model the consequences of using solar radiation geoengineering on a marine ecosystem. There are many dangers associated with deliberate human interventions in the climate system and a lot more work is needed to fully appreciate the consequences of intervening in this way.”Read more
May 30, 2013 — A multi-national team of researchers has identified genetic markers that predict educational attainment by pooling data from more than 125,000 individuals in the United States, Australia, and 13 western European countries.
The study, which appears in the journal Science, was conducted by the Social Science Genetic Association Consortium (SSGAC), which includes researchers at NYU, Erasmus University, Cornell University, Harvard University, the University of Bristol, and the University of Queensland, among other institutions.
The SSGAC conducted what is called a genome-wide association study (GWAS) to explore the link between genetic variation and educational attainment — the number of years of schooling completed by an individual and whether he or she graduated college. In a GWAS, researchers test hundreds of thousands of genetic markers for association with some characteristics such as a disease, trait or life outcome.
Because the sample included people from different countries — where markers for schooling vary significantly — the research team adopted the International Standard Classification of Education (ISCED) scale, which is a commonly used method for establishing a uniform measure of educational attainment across cohorts.
Anticipating that very large samples would be required to credibly detect genetic associations, the SSGAC researchers assembled a total sample size more than 10 times larger than any previous genetic study of any social-scientific outcome. The team examined associations between educational attainment and genetic variants called single-nucleotide polymorphisms, or SNPs, which are tiny changes at a single location in a person’s genetic code.
The study found that the genetic markers with the strongest effects on educational attainment could each only explain two one-hundredths of a percentage point (0.02 percent). To put that figure into perspective, it is known from earlier research that the SNP with the largest effect on human height accounts for about 0.40 percent of the variation.
Combining the two million examined SNPs, the SSGAC researchers were able to explain about 2 percent of the variation in educational attainment across individuals, and anticipate that this figure will rise as larger samples become available.
“We hope that our findings will eventually be useful for understanding biological processes underlying learning, memory, reading disabilities and cognitive decline in the elderly,” said co-author Daniel Benjamin, a behavioral economist at Cornell who is a co-director of the SSGAC.
“Another contribution of our study is that it will strengthen the methodological foundations of social-science genetics,” said David Cesarini, an NYU assistant professor at the Center for Experimental Social Science and the Center for Neuroeconomics, who also co-directs the SSGAC. “We used 125,000 individuals to conduct this study. Previous studies used far smaller samples, sometimes as small as 100 individuals and rarely more than 10,000. These small samples make sense under the assumption that individual genes have large effects. However, if genes have small effects, as our study shows, then sample sizes need to be very large to produce robust findings that will reliably replicate in other samples.”
The researchers were careful to note that they have not discovered “the gene for education” or that these findings somehow imply that a person’s educational attainment is determined at birth.
“For most outcomes that we study as social scientists, genetic influences are likely to operate through environmental channels that are modifiable,” explained NYU sociologist Dalton Conley, one of the study’s co-authors who also serves on the Advisory Board of the SSGAC. “We have now taken a small but important first step toward identifying the specific genetic variants that predict educational attainment. Armed with this knowledge, we can now begin to examine how other factors — including public policy, parental roles, and economic status — dampen or amplify genetic effects and ultimately devise better remedies to bolster educational outcomes.”Read more