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Showing posts from March, 2019

Five new frog species from Madagascar

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An adult male Mini scule resting on a fingertip. Scientists at Ludwig-Maximilians-Universitaet (LMU) in Munich and the Bavarian State Collection of Zoology have named five new species of frogs found across the island of Madagascar. The largest could sit on your thumbnail, the smallest is hardly longer than a grain of rice. Madagascar, an island a little larger than mainland France, has more than 350 frog species. This number of recognized species is constantly rising, and many of the newly named species are very small. Mark D. Scherz, a PhD candidate at LMU Munich, and Dr. Frank Glaw, Head of the Herpetology Section at the Bavarian State Collection of Zoology in Munich, together with colleagues at the Technical University of Braunschweig and the University of Antananarivo have named five new species of tiny frogs found across the island. Their study appears in the online journal  PLOS ONE . The five new species belong to a group of frogs commonly referred to as 'n

66-million-year-old deathbed linked to dinosaur-killing meteor

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Fossilized fish piled one atop another, suggesting that they were flung ashore and died stranded together on a sand bar after the wave from the seiche withdrew. The beginning of the end started with violent shaking that raised giant waves in the waters of an inland  sea in what is now North Dakota. Then, tiny glass beads began to fall like birdshot from the heavens. The rain of glass was so heavy it may have set fire to much of the vegetation on land. In the water, fish struggled to breathe as the beads clogged their gills. The heaving sea turned into a 30-foot wall of water when it reached the mouth of a river, tossing hundreds, if not thousands, of fresh-water fish -- sturgeon and paddlefish -- onto a sand bar and temporarily reversing the flow of the river. Stranded by the receding water, the fish were pelted by glass beads up to 5 millimeters in diameter, some burying themselves inches deep in the mud. The torrent of rocks, like fine sand, and small glass beads con

Researchers discover the source of new neurons in brain's hippocampus

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The dentate gyrus of mouse hippocampus at postnatal day 7, blue is nuclei marker, green is progeny of HOPX-expressing progenitor cells, and red is marker of cell proliferation. It was once believed that mammals were born with the entire supply of neurons they would have for a lifetime. However, over the past few decades, neuroscientists have found that at least two brain regions -- the centers of the sense of smell and the hippocampus, the seat of learning and memory -- grow new neurons throughout life. Researchers from the Perelman School of Medicine at the University of Pennsylvania have shown, in mice, that one type of stem cell that makes adult neurons is the source of this lifetime stock of new cells in the hippocampus. Published this week in  Cell , these findings may help neuroscientists figure out how to maintain youthful conditions for learning and memory, and repair and regenerate parts of the brain after injury and aging. "We've shown for the first t

People don’t become ‘adults’ until their 30s

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You're an adult, but your brain might not be, experts say. You're legally an adult when you turn 18, in most of the United States. However, from a scientific perspective, adulthood is an unsolved mystery. People do not become proper adults until they have entered their thirties, according to brain researchers who say hard definitions of adulthood are looking “increasingly absurd”. While the UK judicial system currently recognises a person of 18 as a mature adult, scientists say people are undergoing significant changes to their brains for many years. The latest research suggests these changes can have significant effects on young people’s behaviour, a s well as making them more susceptible to mental health disorders. Processes that involve boosting the conductivity of nerves, building neural networks and “pruning” away unwanted connections begin in the womb and continue for decades. A burst of upheaval in the brain is thought to account for the notoriously difficult beh

Dynamic hydrogel used to make 'soft robot' components and LEGO-like building blocks

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LEGO-like hydrogel building blocks patterned with tiny fluid channels can be assembled into complex microfluidic devices and then sealed tightly together. Using a new type of dual polymer material capable of responding dynamically to its environment, Brown University researchers have developed a set of modular hydrogel components that could be useful in a variety of "soft robotic" and biomedical applications. The components, which are patter ned by a 3D printer, are capable of bending, twisting or sticking together in response to treatment with certain chemicals. For a paper published in the journal   Polymer Chemistry , the researchers demonstrated a soft gripper capable of actuating on demand to pick up small objects. They also designed LEGO-like hydrogel building blocks that can be carefully assembled then tightly sealed together to form customized microfluidic devices -- "lab-on-a-chip" systems used for drug screening, cell cultures and other applic

Evidence for a Human Geomagnetic Sense

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Research shows the changes in alpha wave amplitude --- a measure of whether the brain is being engaged or is in a resting or "autopilot" mode --- following rotations of an Earth-strength magnetic field. On the left, counterclockwise rotations induce a widespread drop in alpha wave amplitude. No drop is observed after clockwise rotation or in the FIXED condition. Scientists develop a robust experiment that shows human brain waves respond to changes in Earth-strength magnetic fields. Many humans are able to unconsciously detect changes in Earth-strength magnetic fields, according to scientists at Caltech and the University of Tokyo. The study, led by geoscientist Joseph Kirschvink (BS, MS '75) and neuroscientist Shin Shimojo at Caltech as well as neuroen gineer Ayu Matani at the University of Tokyo, offers experimental evidence that human brain waves respond to controlled changes in Earth-strength magnetic fields. Kirschvink and Shimojo say this is the first

People who don't drink may still suffer harms from alcohol

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Dizziness of a young woman Harms to people resulting from alcohol consumption by others in Germany in 2014 are assessed in a study published in the open access journal  BMC Medicine . Much of the research into alcohol-associated harms investigates harm to the drinker, not to other individuals. Researchers at Institute fo r Therapy Research in Bayern, Germany, estimated the harms caused to others by alcohol during pregnancy, in road traffic accidents, and as a result of interpersonal violence. The authors conclude that the harmful effects of alcohol on people other than the drinker need to be recognized as a public health problem, and effective ways of preventing such harms are required. Dr Ludwig Kraus, the corresponding author, said: "This study estimates some of the most severe harms that alcohol use may cause to other people than the drinker, namely fetal alcohol syndrome (FAS), fetal alcohol spectrum disorders (FASD), road traffic fatalities caused by drunk drivers,

Prenatal testosterone linked to long-term effects in females who share womb with male twin

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Newborn boy - girl twins. Women who shared their mother's womb with a male twin are less likely to graduate from high school or college, have earned less by their early 30s, a nd have lower fertility and marriage rates when compared with twins who are both female, according to new Northwestern University research. In the largest and most rigorous study of its kind, Northwestern University and Norwegian School of Economics researchers examined data on all twin births in Norway over a 12-year period to find that females exposed in utero to a male twin experienced adverse educational and labor outcomes along with altered patterns of marriage and fertility as adults. "Nobody has been able to study how male twins impact their twin sisters at such a large scale," said study corresponding author Krzysztof Karbownik, an economist and research associate at Northwestern University's Institute for Policy Research (IPR). "This is the first study to track peopl

Scientists hunt down the brain circuit responsible for alcohol cravings

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Confocal analysis at 63x magnification, followed by the three-dimensional reconstruction of neuronal cell bodies and branches. The image shows an example of eYFP and CRF in the same neuron. This rendered isosurface analysis demonstrated the colocalization of CRF immunoreactivity within CeA neurons that also expressed Cre-dependent eYFP and validates the crh-Cre rat as a tool to gain more direct access to CRF neurons to study their functional neuroanatomy. Scientists at Scripps Research have found that they can reverse the desire to drink in alcohol-dependent rats -- with the flip of a switch. The researchers were able to use lasers to temporarily inactivate a specific neuronal population, reversing alcohol-seeking behavior and even reducing the physical symptoms of withdrawal. "This discovery is exciting -- it means we have another piece of the puzzle to explain the neural mechanism driving alcohol consumption," says Olivier George, PhD, an associate professor at

Researchers create hydrogen fuel from seawater

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A prototype device used solar energy to create hydrogen fuel from seawater. Stanford researchers have devised a way to generate hydrogen fuel using solar power, electrodes and saltwater from San Francisco Bay. The findings, published March 18 in  Proceedings of the National Academy of Sciences , demonstrate a new way of separating hydrogen and oxygen gas from seawater via electricity. Existing water-splitting methods rely on highly purified water, which is a precious resource and costly to produce. Theoretically, to power cities and cars, "you need so much hydrogen it is not conceivable to use purified water," said Hongjie Dai, J.G. Jackson and C.J. Wood professor in chemistry at Stanford and co-senior author on the paper. "We barely have enough water for our current needs in California." Hydrogen is an appealing option for fuel because it doesn't emit carbon dioxide, Dai said. Burning hydrogen produces only water and should ease worsening clima