Looking back to the cradle of our universe: Astronomers spot what may be one of most distant galaxies known

NASA’s Spitzer and Hubble Space Telescopes have spotted what might be one of the most distant galaxies known, harkening back to a time when our universe was only about 650 million years old (our universe is 13.8 billion years old). The galaxy, known as Abell2744 Y1, is about 30 times smaller than our Milky Way galaxy and is producing about 10 times more stars, as is typical for galaxies in our young universe.The discovery comes from the Frontier Fields program, which is pushing the limits of how far back we can see into the distant universe using NASA’s multi-wavelength suite of Great Observatories. Spitzer sees infrared light, Hubble sees visible and shorter-wavelength infrared light, and NASA’s Chandra X-ray Observatory sees X-rays. The telescopes are getting a boost from natural lenses: they peer through clusters of galaxies, where gravity magnifies the light of more distant galaxies.The Frontier Fields program will image six galaxy clusters in total. Hubble images of the region are used to spot candidate distant galaxies, and then Spitzer is needed to determine if the galaxies are, in fact, as far as they seem. Spitzer data also help determine how many stars are in the galaxy.These early results from the program come from images of the Abell 2744 galaxy cluster. The distance to this galaxy, if confirmed, would make it one of the farthest known. Astronomers say it has a redshift of 8, which is a measure of the degree to which its light has been shifted to redder wavelengths due to the expansion of our universe. The farther a galaxy, the higher the redshift. The farthest confirmed galaxy has a redshift of more than 7. …

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New links found between sleep duration, depression

A genetic study of adult twins and a community-based study of adolescents both report novel links between sleep duration and depression. The studies are published in the Feb. 1 issue of the journal Sleep.”Healthy sleep is a necessity for physical, mental and emotional well-being,” said American Academy of Sleep Medicine President Dr. M. Safwan Badr. “This new research emphasizes that we can make an investment in our health by prioritizing sleep.”A study of 1,788 adult twins is the first to demonstrate a gene by environment interaction between self-reported habitual sleep duration and depressive symptoms. Results suggest that sleep durations outside the normal range increase the genetic risk for depressive symptoms. Among twins with a normal sleep duration of seven to 8.9 hours per night, the total heritability of depressive symptoms was 27 percent. However, the genetic influence on depressive symptoms increased to 53 percent among twins with a short sleep duration of five hours per night and 49 percent among those who reported sleeping 10 hours per night.”We were surprised that the heritability of depressive symptoms in twins with very short sleep was nearly twice the heritability in twins sleeping normal amounts of time,” said principal investigator Dr. Nathaniel Watson, associate professor of neurology and co-director of the University of Washington Medicine Sleep Center in Seattle, Wash. …

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Review of the Breastflow Memory Pump by The First Years

I’ve been pumping and donating since Ivy was 2 weeks old. I’ve used two pumps, the Ameda Purely Yours and the Medela Personal Double Pump (see my review here). Breast pumps are a big investment and are usually non-returnable. You can’t test them out in the store, so you have to go by reputation, cost, or word-of-mouth.The First Years company just came out with a new double electric breast pump, the Breastflow Memory Pump (approx $179), and offered to send me one to test out. It’s an upgrade of their earlier model, the miPump Double Electric Pump (approx $79). The big change from the old model to the new? An electronically controlled pump that can store data (time, duration, suction & speed …

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Darwin’s dilemma resolved: Evolution’s ‘big bang’ explained by five times faster rates of evolution

Sep. 12, 2013 — A new study led by Adelaide researchers has estimated, for the first time, the rates of evolution during the “Cambrian explosion” when most modern animal groups appeared between 540 and 520 million years ago.The findings, published online today in the journal Current Biology, resolve “Darwin’s dilemma”: the sudden appearance of a plethora of modern animal groups in the fossil record during the early Cambrian period.”The abrupt appearance of dozens of animal groups during this time is arguably the most important evolutionary event after the origin of life,” says lead author Associate Professor Michael Lee of the University of Adelaide’s School of Earth and Environmental Sciences and the South Australian Museum.”These seemingly impossibly fast rates of evolution implied by this Cambrian explosion have long been exploited by opponents of evolution. Darwin himself famously considered that this was at odds with the normal evolutionary processes.”However, because of the notorious imperfection of the ancient fossil record, no-one has been able to accurately measure rates of evolution during this critical interval, often called evolution’s Big Bang.”In this study we’ve estimated that rates of both morphological and genetic evolution during the Cambrian explosion were five times faster than today — quite rapid, but perfectly consistent with Darwin’s theory of evolution.”The team, including researchers from the Natural History Museum in London, quantified the anatomical and genetic differences between living animals, and established a timeframe over which those differences accumulated with the help of the fossil record and intricate mathematical models. Their modelling showed that moderately accelerated evolution was sufficient to explain the seemingly sudden appearance of many groups of advanced animals in the fossil record during the Cambrian explosion.The research focused on arthropods (insects, crustaceans, arachnids and their relatives), which are the most diverse animal group in both the Cambrian period and present day.”It was during this Cambrian period that many of the most familiar traits associated with this group of animals evolved, like a hard exoskeleton, jointed legs, and compound (multi-faceted) eyes that are shared by all arthropods. We even find the first appearance in the fossil record of the antenna that insects, millipedes and lobsters all have, and the earliest biting jaws.” says co-author Dr Greg Edgecombe of the Natural History Museum.

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Interstellar winds buffeting our solar system have shifted direction

Sep. 5, 2013 — Scientists, including University of New Hampshire astrophysicists involved in NASA’s Interstellar Boundary Explorer (IBEX) mission, have discovered that the particles streaming into the solar system from interstellar space have likely changed direction over the last 40 years.The finding helps scientists map our location within the Milky Way galaxy and is crucial for understanding our place in the cosmos through the vast sweep of time — where we’ve come from, where we’re currently located, and where we’re going in our journey through the galaxy.Additionally, scientists now gain deeper insight into the dynamic nature of the interstellar winds, which has major implications on the size, structure, and nature of our sun’s heliosphere — the gigantic bubble that surrounds our solar system and helps shield us from dangerous incoming galactic radiation.The results, based on data spanning four decades from 11 different spacecraft, including IBEX, were published in the journal Science September 5, 2013.”It was very surprising to find that changes in the interstellar flow show up on such short time scales because interstellar clouds are astronomically large,” says Eberhard Möbius, UNH principal scientist for the IBEX mission and co-author on the Science paper. Adds Möbius, “However, this finding may teach us about the dynamics at the edges of these clouds — while clouds in the sky may drift along slowly, the edges often are quite fuzzy and dynamic. What we see could be the expression of such behavior.”The data from the IBEX spacecraft show that neutral interstellar atoms are flowing into the solar system from a different direction than previously observed. Interstellar atoms flow past Earth as the interstellar cloud surrounding the solar system passes the sun at 23 kilometers per second (50,000 miles per hour).The latest IBEX measurements of the interstellar wind direction differed from those made by the Ulysses spacecraft in the 1990s. That difference led the IBEX team to compare the IBEX measurements to data gathered by 11 spacecraft between 1972 and 2011. The scientists wanted to gather as much evidence from as many sources as possible to determine whether the newer instruments simply provided more accurate results, or whether the wind direction itself changed over the years.The various sets of observations relied on three different methods to measure the incoming interstellar wind. IBEX and Ulysses directly measured neutral helium atoms as they coursed through the inner solar system. IBEX’s measurements are close to Earth, while Ulysses’ measurements were taken between 1.3 and 2 times further from the sun.In the final analysis, the direction of the wind obtained most recently by IBEX data differs from the direction obtained from the earlier measurements, which strongly suggests the wind itself has changed over time.”Prior to this study, we were struggling to understand why our current measurements from IBEX differed from those of the past,” says co-author Nathan Schwadron, lead scientist for the IBEX Science Operations Center at UNH. “We are finally able to resolve why these fundamental measurements have been changing with time: we are moving through a changing interstellar medium.”

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West Antarctica ice sheet existed 20 million years earlier than previously thought

Sep. 4, 2013 — The results of research conducted by professors at UC Santa Barbara and colleagues mark the beginning of a new paradigm for our understanding of the history of Earth’s great global ice sheets. The research shows that, contrary to the popularly held scientific view, an ice sheet on West Antarctica existed 20 million years earlier than previously thought.The findings indicate that ice sheets first grew on the West Antarctic subcontinent at the start of a global transition from warm greenhouse conditions to a cool icehouse climate 34 million years ago. Previous computer simulations were unable to produce the amount of ice that geological records suggest existed at that time because neighboring East Antarctica alone could not support it.The findings were published today in Geophysical Research Letters, a journal of the American Geophysical Union.Given that more ice grew than could be hosted only on East Antarctica, some researchers proposed that the missing ice formed in the northern hemisphere, many millions of years before the documented ice growth in that hemisphere, which started about 3 million years ago. But the new research shows it is not necessary to have ice hosted in the northern polar regions at the start of greenhouse-icehouse transition.Earlier research published in 2009 and 2012 by the same team showed that West Antarctica bedrock was much higher in elevation at the time of the global climate transition than it is today, with much of its land above sea level. The belief that West Antarctic elevations had always been low lying (as they are today) led researchers to ignore it in past studies. The new research presents compelling evidence that this higher land mass enabled a large ice sheet to be hosted earlier than previously realized, despite a warmer ocean in the past.”Our new model identifies West Antarctica as the site needed for the accumulation of the extra ice on Earth at that time,” said lead author Douglas S. Wilson, a research geophysicist in UCSB’s Department of Earth Science and Marine Science Institute. “We find that the West Antarctic Ice Sheet first appeared earlier than the previously accepted timing of its initiation sometime in the Miocene, about 14 million years ago. In fact, our model shows it appeared at the same time as the massive East Antarctic Ice Sheet some 20 million years earlier.”Wilson and his team used a sophisticated numerical ice sheet model to support this view. …

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Mystery in blot clotting disorder solved

Aug. 27, 2013 — Fifteen years ago, a hematologist came to Dianna Milewicz, M.D., Ph.D., with a puzzle: Multiple generations of an East Texas family suffered from a moderately severe bleeding disorder, but it wasn’t hemophilia.”No surgeon would do elective surgery because they bled too much after surgery,” said Milewicz, professor and director of the Division of Medical Genetics at The University of Texas Health Science Center at Houston (UTHealth). “So we collected DNA and plasma from the family and were able to determine that a genetic variant in the Factor V gene was causing production of an abnormal form of the Factor V protein, which we called FV-Short. Factor V is a protein known to be important for the blood to clot.”But her team at the UTHealth Medical School couldn’t pinpoint exactly how the variation was causing the clotting problem until they collaborated with Björn Dahlbӓck, M.D., Ph.D., from Lund University, Malmö, Sweden.”Dr. Dahlbӓck is a world expert on Factor V and he was very excited about the research,” said Milewicz, who holds the President George H.W. Bush Chair in Cardiovascular Research. She is also on the faculty of The University of Texas Graduate School of Biomedical Sciences and director of the John Ritter Research Program in Aortic and Vascular Diseases at UTHealth.”I was indeed very excited when hearing about the puzzling results because the knowledge at the time on the role of FV in coagulation could not explain the bleeding disorder. It has been a great privilege to work with Dr. Milewicz and her colleagues to decode the unexpected and intriguing mechanisms on how FV-Short caused the bleeding disorder,” said Dahlbäck who holds the chair as professor of Blood Coagulation Research at Lund University, Malmö, Sweden.The results were published in today’s online issue of the Journal of Clinical Investigation. Milewicz and Dahlbäck are senior co-authors.Genes make proteins that do everything from giving cells shape and structure to helping carry out biological processes. …

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Extremely preterm infants and risk of developing neurodevelopmental impairment later in childhood

Aug. 26, 2013 — A meta-analysis of previously reported studies by Gregory P. Moore, M.D., F.R.C.P.C., of The Ottawa Hospital, Ontario, Canada, and colleagues examined the rate of moderate to severe and severe neurodevelopmental impairment by gestational age in extremely preterm survivors followed up between ages 4 and 8 years, and determined whether there is a significant difference in impairment rates between the successive weeks of gestation of survivors.Share This:The search of English-language publications found nine studies that met inclusion criteria of being published after 2004, a prospective cohort study, follow-up rate of 65 percent or more, use of standardized testing or classification for impairment, reporting by gestation, and meeting prespecified definitions of impairment. Researchers then extracted data using a structured data collection form and investigators were contacted for data clarification.According to the study results, all extremely preterm infant survivors have a substantial likelihood of developing moderate to severe impairment. Wide confidence intervals at the lower gestations (eg. at 22 weeks, 43 percent) and high heterogeneity at the higher gestations (eg. at 25 weeks, 24 percent) limit the results. There was a statistically significant absolute decrease in moderate to severe impairment between each week of gestation.”Knowledge of these data, including the limitations, should facilitate discussion during the shared decision-making process about care plans for these infants, particularly in centers without their own data,” the study concludes.Share this story on Facebook, Twitter, and Google:Other social bookmarking and sharing tools:|Story Source: The above story is based on materials provided by American Medical Association (AMA), via Newswise. Note: Materials may be edited for content and length. For further information, please contact the source cited above. …

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Recurrence risk for autism spectrum disorders examined for full, half siblings

Aug. 19, 2013 — A Danish study of siblings suggests the recurrence risks for autism spectrum disorders (ASDs) varied from 4.5 percent to 10.5 percent depending on the birth years, which is higher than the ASD risk of 1.18 percent in the overall Danish population, according to a study published by JAMA Pediatrics, a JAMA Network publication.ASDs are neurodevelopmental disorders that are characterized by difficulties in social interaction and communication and also include repetitive behavior and narrow interests. Childhood autism (CA) accounts for about 30 percent of all ASD cases and the prevalence of ASDs has increased during the last two decades, according to the study background.Therese K. Grønborg, M.Sc., of Aarhus University, Denmark, and colleagues conducted a population-based study in Denmark of all children (about 1.5 million) born between 1980 and 2004. They identified a maternal sibling group derived from mothers with at least two children and a paternal sibling group derived from fathers with at least two children.”To date, this is the first population-based study to examine the recurrence risk for autism spectrum disorders (ASDs), including time trends, and the first study to consider the ASDs recurrence risk for full- and half-siblings,” the authors note in the study.The study results suggest an almost seven-fold increase in ASDs risk if an older sibling had an ASD diagnosis compared with no ASD diagnoses in older siblings. In children with the same mother, the adjusted relative recurrence risk of 7.5 in full siblings was significantly higher than the risk of 2.4 in half siblings. In children with the same father, the adjusted relative recurrence risk was 7.4 in full siblings and significant, but no statistically significant increased risk was observed among paternal half siblings, the results also indicate.”The difference in the recurrence risk between full and half siblings supports the role of genetics in ASDs, while the significant recurrence risk in maternal half-siblings may support the role of factors associated with pregnancy and the maternal intrauterine environment in ASDs,” the study concludes.

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Waking up to a new year: Exoplanet orbits its star in 8.5 hours

Aug. 19, 2013 — In the time it takes you to complete a single workday, or get a full night’s sleep, a small fireball of a planet 700 light-years away has already completed an entire year.Researchers at MIT have discovered an Earth-sized exoplanet named Kepler 78b that whips around its host star in a mere 8.5 hours — one of the shortest orbital periods ever detected. The planet is extremely close to its star — its orbital radius is only about three times the radius of the star — and the scientists have estimated that its surface temperatures may be as high as 3,000 degrees Kelvin, or more than 5,000 degrees Fahrenheit. In such a scorching environment, the top layer of the planet is likely completely melted, creating a massive, roiling ocean of lava.What’s most exciting to scientists is that they were able to detect light emitted by the planet — the first time that researchers have been able to do so for an exoplanet as small as Kepler 78b. This light, once analyzed with larger telescopes, may give scientists detailed information about the planet’s surface composition and reflective properties.Kepler 78b is so close to its star that scientists hope to measure its gravitational influence on the star. Such information may be used to measure the planet’s mass, which could make Kepler 78b the first Earth-sized planet outside our own solar system whose mass is known.The researchers reported their discovery of Kepler 78b in The Astrophysical Journal.In a separate paper, published in Astrophysical Journal Letters, members of that same group, along with others at MIT and elsewhere, observed KOI 1843.03, a previously discovered exoplanet with an even shorter orbital period: just 4 1/4 hours. The group, led by physics professor emeritus Saul Rappaport, determined that in order for the planet to maintain its extremely tight orbit around its star, it would have to be incredibly dense, made almost entirely of iron — otherwise, the immense tidal forces from the nearby star would rip the planet to pieces.”Just the fact that it’s able to survive there implies that it’s very dense,” says Josh Winn, an associate professor of physics at MIT, and co-author on both papers. “Whether nature actually makes planets that are dense enough to survive even closer in, that’s an open question, and would be even more amazing.”Dips in the dataIn their discovery of Kepler 78b, the team that wrote the Astrophysical Journal paper looked through more than 150,000 stars that were monitored by the Kepler Telescope, a NASA space observatory that surveys a slice of the galaxy. Scientists are analyzing data from Kepler in hopes of identifying habitable, Earth-sized planets.The goal for Winn and his colleagues was to look for Earth-sized planets with very short orbital periods.”We’ve gotten used to planets having orbits of a few days,” Winn says. “But we wondered, what about a few hours? …

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New species of carnivore looks like a cross between a house cat and a teddy bear

Aug. 15, 2013 — Observed in the wild, tucked away in museum collections, and even exhibited in zoos around the world — there is one mysterious creature that has been a victim of mistaken identity for more than 100 years. A team of Smithsonian scientists, however, uncovered overlooked museum specimens of this remarkable animal, which took them on a journey from museum cabinets in Chicago to cloud forests in South America to genetics labs in Washington, D.C. The result: the olinguito (Bassaricyon neblina) — the first carnivore species to be discovered in the American continents in 35 years.The team’s discovery is published in the Aug. 15 issue of the journal ZooKeys.The olinguito (oh-lin-GHEE-toe) looks like a cross between a house cat and a teddy bear. It is actually the latest scientifically documented member of the family Procyonidae, which it shares with raccoons, coatis, kinkajous and olingos. The 2-pound olinguito, with its large eyes and woolly orange-brown fur, is native to the cloud forests of Colombia and Ecuador, as its scientific name, “neblina” (Spanish for “fog”), hints. In addition to being the latest described member of its family, another distinction the olinguito holds is that it is the newest species in the order Carnivora — an incredibly rare discovery in the 21st century.”The discovery of the olinguito shows us that the world is not yet completely explored, its most basic secrets not yet revealed,” said Kristofer Helgen, curator of mammals at the Smithsonian’s National Museum of Natural History and leader of the team reporting the new discovery. “If new carnivores can still be found, what other surprises await us? So many of the world’s species are not yet known to science. …

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Shortening tails gave early birds a leg up

Aug. 13, 2013 — A radical shortening of their bony tails over 100 million years ago enabled the earliest birds to develop versatile legs that gave them an evolutionary edge, a new study shows.A team led by Oxford University scientists examined fossils of the earliest birds from the Cretaceous Period, 145-66 million years ago, when early birds, such as Confuciusornis, Eoenantiornis, and Hongshanornis, lived alongside their dinosaur kin. At this point birds had already evolved powered flight, necessitating changes to their forelimbs, and the team investigated how this new lifestyle related to changes in their hind limbs (legs).The team made detailed measurements of early bird fossils from all over the world including China, North America, and South America. An analysis of this data showed that the loss of their long bony tails, which occurred after flight had evolved, led to an explosion of diversity in the hind limbs of early birds, prefiguring the amazing variety of talons, stilts, and other specialised hind limbs that have helped to make modern birds so successful.A report of the research is published this week in Proceedings of the Royal Society B.’These early birds were not as sophisticated as the birds we know today — if modern birds have evolved to be like stealth bombers then these were more like biplanes,’ said Dr Roger Benson of Oxford University’s Department of Earth Sciences, who led the research. ‘Yet what surprised us was that despite some still having primitive traits, such as teeth, these early birds display an incredibly diverse array of versatile legs.’By comparing measurements of the main parts of the legs of early birds — upper leg, shin, and foot — to those of their dinosaur relatives Dr Benson and co-author Dr Jonah Choiniere of the University of the Witwatersrand, South Africa, were able to determine whether bird leg evolution was exceptional compared to leg evolution in dinosaurs.’Our work shows that, whilst they may have started off as just another type of dinosaur, birds quickly made a rather special evolutionary breakthrough that gave them abilities and advantages that their dinosaur cousins didn’t have,’ said Dr Rogers. ‘Key to this special ‘birdness’ was losing the long bony dinosaur tail — as soon as this happened it freed up their legs to evolve to become highly versatile and adaptable tools that opened up new ecological niches.’It was developing these highly versatile legs, rather than powered flight, that saw the evolutionary diversification of early birds proceed faster than was generally true of other dinosaurs.

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Motional layers found in the brain: Neurobiologists discover elementary motion detectors in the fruit fly

Aug. 7, 2013 — Recognising movement and its direction is one of the first and most important processing steps in any visual system. By this way, nearby predators or prey can be detected and even one’s own movements are controlled. More than fifty years ago, a mathematical model predicted how elementary motion detectors must be structured in the brain. However, which nerve cells perform this job and how they are actually connected remained a mystery. Scientists at the Max Planck Institute of Neurobiology in Martinsried have now come one crucial step closer to this “holy grail of motion vision”: They identified the cells that represent these so-called “elementary motion detectors” in the fruit fly brain. The results show that motion of an observed object is processed in two separate pathways. In each pathway, motion information is processed independently of one another and sorted according to its direction.Ramón y Cajal, the famous neuroanatomist, was the first to examine the brains of flies. Almost a century ago, he thus discovered a group of cells he described as “curious elements with two tufts.” About 50 years later, German physicist Werner Reichardt postulated from his behavioural experiments with flies that they possess “elementary motion detectors,” as he referred to them. These detectors compare changes in luminance between two neighbouring photoreceptor units, or facets, in the fruit fly’s eye for every point in the visual space. …

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Bringing light to a halt: Physicists freeze motion of light for a minute

Aug. 6, 2013 — Physicists in Darmstadt have been able to stop something that has the greatest possible speed and that never really stops. We’re talking about light. About a decade ago, physicists stopped it very for just a moment. In previous years, this extended towards stop times of a few seconds for simple light pulses in extremely cold gases and special crystals. But now the researchers at Darmstadt extended the possible duration and applications for freezing the motion of light considerably.The physicists, headed by Thomas Halfmann at the Institute of Applied Physics of the Technische Universität Darmstadt, stopped light for about one minute. They were also able to save images that were transferred by the light pulse into the crystal for a minute — a million times longer than previously possible.The researchers achieved the record by cleverly combining various known methods of their field. The result will have practical significance in future data processing systems that operate using light.To stop the light, the physicists used a glass-like crystal that contains a low concentration of ions — electrically charged atoms — of the element praseodymium. The experimental setup also includes two laser beams. One is part of the deceleration unit, while the other is to be stopped. …

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Greening of the Earth pushed way back in time

July 22, 2013 — Conventional scientific wisdom has it that plants and other creatures have only lived on land for about 500 million years, and that landscapes of the early Earth were as barren as Mars.A new study, led by geologist Gregory J. Retallack of the University of Oregon, now has presented evidence for life on land that is four times as old — at 2.2 billion years ago and almost half way back to the inception of the planet.That evidence, which is detailed in the September issue of the journal Precambrian Research, involves fossils the size of match heads and connected into bunches by threads in the surface of an ancient soil from South Africa. They have been named Diskagma buttonii, meaning “disc-shaped fragments of Andy Button,” but it is unsure what the fossils were, the authors say.”They certainly were not plants or animals, but something rather more simple,” said Retallack, professor of geological sciences and co-director of paleontological collections at the UO’s Museum of Natural and Cultural History. The fossils, he added, most resemble modern soil organisms called Geosiphon, a fungus with a central cavity filled with symbiotic cyanobacteria.”There is independent evidence for cyanobacteria, but not fungi, of the same geological age, and these new fossils set a new and earlier benchmark for the greening of the land,” he said. “This gains added significance because fossil soils hosting the fossils have long been taken as evidence for a marked rise in the amount of oxygen in the atmosphere at about 2.4 billion to 2.2 billion years ago, widely called the Great Oxidation Event.”By modern standards, in which Earth’s air is now 21 percent oxygen, this early rise was modest, to about 5 percent oxygen, but it represented a rise from vanishingly low oxygen levels earlier in geological time.Demonstrating that Diskagma are fossils, Retallack said, was a technical triumph because they were too big to be completely seen in a standard microscopic slide and within rock that was too dark to see through in slabs. The samples were imaged using powerful X-rays of a cyclotron, a particle accelerator, at the Lawrence Berkeley National Laboratory in California.The images enabled a three-dimensional restoration of the fossils’ form: odd little hollow urn-shaped structures with a terminal cup and basal attachment tube. “At last we have an idea of what life on land looked like in the Precambrian,” Retallack said. “Perhaps with this search image in mind, we can find more and different kinds of fossils in ancient soils.”In their conclusion, the researchers noted that their newly named fossil Diskagma is comparable in morphology and size to Thucomyces lichenoides, a fossil dating to 2.8 billion years ago and also found in South Africa, but its composition, including interior structure and trace elements, is significantly different.Diskagma also holds some similarities to three living organisms, which were illustrated microscopically in the study: the slime mold Leocarpus fragilis as found in Oregon’s Three Sisters Wilderness; the lichen Cladonia ecmocyna gathered near Fishtrap Lake in Montana; and the fungus Geosiphon pyriformis from near Darmstadt, Germany.The new fossil, the authors concluded, is a promising candidate for the oldest known eukaryote –an organism with cells that contain complex structures, including a nucleus, within membranes.”Researchers at the UO are collaborating with scientists from around the world to create new knowledge with far-reaching applications,” said Kimberly Andrews Espy, UO vice president for research and innovation, and dean of the graduate school. “This research by Dr. Retallack and his team opens new doors of inquiry about the origins of ancient life on Earth.”

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Ancient ice melt unearthed in Antarctic mud: 20 meter sea level rise, five million years ago

July 21, 2013 — Global warming five million years ago may have caused parts of Antarctica’s large ice sheets to melt and sea levels to rise by approximately 20 metres, scientists report today in the journal Nature Geoscience.The researchers, from Imperial College London, and their academic partners studied mud samples to learn about ancient melting of the East Antarctic ice sheet. They discovered that melting took place repeatedly between five and three million years ago, during a geological period called Pliocene Epoch, which may have caused sea levels to rise approximately ten metres.Scientists have previously known that the ice sheets of West Antarctica and Greenland partially melted around the same time. The team say that this may have caused sea levels to rise by a total of 20 metres.The academics say understanding this glacial melting during the Pliocene Epoch may give us insights into how sea levels could rise as a consequence of current global warming. This is because the Pliocene Epoch had carbon dioxide concentrations similar to now and global temperatures comparable to those predicted for the end of this century.Dr Tina Van De Flierdt, co-author from the Department of Earth Science and Engineering at Imperial College London, says: “The Pliocene Epoch had temperatures that were two or three degrees higher than today and similar atmospheric carbon dioxide levels to today. Our study underlines that these conditions have led to a large loss of ice and significant rises in global sea level in the past. Scientists predict that global temperatures of a similar level may be reached by the end of this century, so it is very important for us to understand what the possible consequences might be.”The East Antarctic ice sheet is the largest ice mass on Earth, roughly the size of Australia. The ice sheet has fluctuated in size since its formation 34 million years ago, but scientists have previously assumed that it had stabilised around 14 million years ago.The team in today’s study were able to determine that the ice sheet had partially melted during this “stable” period by analysing the chemical content of mud in sediments. These were drilled from depths of more than three kilometres below sea level off the coast of Antarctica.Analysing the mud revealed a chemical fingerprint that enabled the team to trace where it came from on the continent. They discovered that the mud originated from rocks that are currently hidden under the ice sheet. The only way that significant amounts of this mud could have been deposited as sediment in the sea would be if the ice sheet had retreated inland and eroded these rocks, say the team.The academics suggest that the melting of the ice sheet may have been caused in part by the fact that some of it rests in basins below sea level. …

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The Red Queen was right: Life must continually evolve to avoid extinction

June 20, 2013 — The death of individual species shouldn’t be the only concern for biologists worried about animal groups, such as frogs or the “big cats,” going extinct. A University of California, Berkeley, study has found that a lack of new, emerging species also contributes to extinction.”Virtually no biologist thinks about the failure to originate as being a major factor in the long term causes of extinction,” said Charles Marshall, director of the UC Berkeley Museum of Paleontology and professor of integrative biology, and co-author of the report. “But we found that a decrease in the origin of new species is just as important as increased extinction rate in driving mammals to extinction.”The effects of such a decrease would play out over millions of years, Marshall said, not rapidly, like the global change Earth is experiencing from human activities. Yet, the findings should help biologists understand the pressures on today’s flora and fauna and what drove evolution and extinction in the past, he added.The results, published June 20 in the journal Science Express, come from a study of 19 groups of mammals that either are extinct or, in the case of horses, elephants, rhinos and others, are in decline from a past peak in diversity. All are richly represented in the fossil record and had their origins sometime in the last 66 million years, during the Cenozoic Era.The study was designed to test a popular evolutionary theory called the Red Queen hypothesis, named after Lewis Carroll’s character who, in the book “Through the Looking Glass,” described her country as a place where “it takes all the running you can do, to keep in the same place.”In biology, this means that animals and plants don’t just disappear because of bad luck in a static and unchanging environment, like a gambler losing it all to a run of bad luck at the slot machines. Instead, they face constant change — a deteriorating environment and more successful competitors and predators — that requires them to continually adapt and evolve new species just to survive.Though the specific cause of declining originations and rising extinctions for these groups is unclear, the researchers concluded that the mammals’ death was not just dumb luck.”Each group has either lost, or is losing, to an increasingly difficult environment,” Marshall said. “These groups’ demise was at least in part due to loss to the Red Queen — that is, a failure to keep pace with a deteriorating environment.”Marshall and former UC Berkeley post-doctoral fellow Tiago Quental found that the animal groups were initially driven to higher diversity until they reached the carrying capacity of their environment, or the maximum number of species their environment could hold. After that, their environment deteriorated to the point where there was too much diversity to be sustained, leading to their extinction.”In fact, our data suggest that biological systems may never be in equilibrium at all, with groups expanding and contracting under persistent and rather, geologically speaking, rapid change,” he said.Marshall and Quental, who is now at the University of Sao Paolo, Brazil, will present their results in two talks this Saturday, June 22, at the Evolution 2013 meeting in Snowbird, Utah.

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New research backs genetic ‘switches’ in human evolution

June 19, 2013 — A Cornell University study offers further proof that the divergence of humans from chimpanzees some 4 million to 6 million years ago was profoundly influenced by mutations to DNA sequences that play roles in turning genes on and off.The study, published June 9 in Nature Genetics, provides evidence for a 40-year-old hypothesis that regulation of genes must play an important role in evolution since there is little difference between humans and chimps in the proteins produced by genes. Indeed, human and chimpanzee proteins are more than 99 percent identical.The researchers showed that the number of evolutionary adaptations to the part of the machinery that regulates genes, called transcription factor binding sites, may be roughly equal to adaptations to the genes themselves.”This is the most comprehensive and most direct analysis to date of the evolution of gene regulatory sequences in humans,” said senior author Adam Siepel, Cornell associate professor of biological statistics and computational biology.”It’s taken these 40 years to get a clear picture of what’s going on in these sequences because we haven’t had the data until very recently,” said Leonardo Arbiza, a postdoctoral researcher in Siepel’s lab and the paper’s lead author.Less than 2 percent of the human genome — the complete set of genetic material — contains genes that code for proteins. In cells, these proteins are instrumental in biological pathways that affect an organism’s health, appearance and behavior. Much less is known about the remaining 98 percent of the genome; however, in the 1960s, scientists recognized that some of the non-protein coding DNA regulates when and where genes are turned on and off, and how much protein they produce. The regulatory machinery works when proteins called transcription factors bind to specific short sequences of DNA that flank the gene, called transcription factor binding sites, and by doing so, switch genes on and off.Among the findings, the study reports that when compared with protein coding genes, binding site DNA shows close to three times as many “weakly deleterious mutations,” that is, mutations that may weaken or make an individual more susceptible to disease, but are generally not severe. Weakly deleterious mutations exist in low frequencies in a population and are eventually weeded out over time. These mutations are responsible for many inherited human diseases.While genes generally tend to resist change, a mutation occasionally leads to a favorable trait and increases across a population; this is called positive selection. By contrast, “transcription factor binding sites show considerable amounts of positive selection,” said Arbiza, with evidence for adaptation in binding sites that regulate genes controlling blood cells, brain function and immunity, among others.”The overall picture shows more evolutionary flexibility in the binding sites than in protein coding genes,” said Siepel. “This has important implications for how we think about human evolution and disease.”This is one of the first studies to combine recent data that identifies transcription factor binding sites, data on human genetic variation and genome comparisons between humans and apes. A new computational method called INSIGHT (Inference of Natural Selection from Interspersed Genomically coHerent elemenTs), designed by Ilan Gronau, a postdoctoral researcher in Siepel’s lab and a co-author of the study, allowed the scientists to integrate these diverse data types and find evidence of natural selection in the regulatory DNA.”Transcription factor binding sites are probably the regulatory elements we know the most about,” said Arbiza. …

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