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  • richardmitnick 4:44 am on September 13, 2014 Permalink | Reply
    Tags: , New York Times,   

    From The New York Times: “A Lost-and-Found Nomad Helps Solve the Mystery of a Swimming Dinosaur” 

    New York Times

    The New York Times

    SEPT. 11, 2014
    KENNETH CHANG

    The first bones came in a cardboard box. Nizar Ibrahim, a paleontologist, was in the Moroccan oasis town of Erfoud at the edge of the Sahara, returning from a dinosaur dig in the sands. Inside the box, brought to him by a nomad, were sediment-encrusted pieces more intriguing than anything he had found himself, including a blade-shaped bone with a reddish streak running through the cross section. He took the bones to a university in Casablanca.

    That was April 2008.

    The next year, he was in Italy visiting colleagues at the Milan Natural History Museum who showed him bones that seemed to be from Spinosaurus aegyptiacus, a strange-looking predatory dinosaur larger than Tyrannosaurus Rex that lived in northern Africa about 95 million years ago.

    He looked at the spines, part of a giant distinctive sail on the back of Spinosaurus. He saw a familiar red line — possibly a passageway for blood vessels long since decayed away — in the cross section of a bone. “My mind started racing,” he said.

    big
    An artist’s interpretation of how Spinosaurus aegyptiacus might have looked and how its size might have compared with that of a human. Credit Davide Bonadonna

    Amazingly, the pieces in Milan and those he had seen a year earlier and 1,200 miles away were from the same ancient skeleton.

    That was the start of an odyssey of diligence and serendipity that led to the unveiling on Thursday of a new skeleton of Spinosaurus. The largest known predatory dinosaur, growing to at least 50 feet in length, Spinosaurus is also the only dinosaur known to be a swimmer that spent a large fraction of its life in the water.

    “It’s probably the most bizarre dinosaur out there,” said Dr. Ibrahim, a graduate student when he saw the first bones, and now a postdoctoral researcher at the University of Chicago.

    Spinosaurus had been an intriguing mystery for decades. The original fossil of the dinosaur, discovered in Egypt a century ago and moved to a German museum, was destroyed during World War II, leaving paleontologists with little more than a few drawings to ponder.

    The new partial skeleton is of a Spinosaurus not fully grown, about 36 feet long. Its forelimbs were large and strong, with scythe-like claws; its hind legs were short, with paddle-shaped feet.

    In an article published online on Thursday by the journal Science, Dr. Ibrahim and an international team of colleagues describe the features that made the dinosaur well suited for swimming and feasting on giant fish that lived in the rivers there.

    Conical teeth in a crocodilian snout overlapped like a snare for trapping fish, and it had nostrils halfway up the skull so it could stick its snout into the water and still breathe.

    With its flat feet, Spinosaurus may have paddled like a duck. It had a long, flexible tail, which it may have used for propulsion. “It’s like a cross between an aquatic bird and a crocodile,” said Paul C. Sereno, a paleontologist at the University of Chicago who was part of the research team.

    On land, Spinosaurus was ungainly. The researchers calculated that its center of mass would have been too far forward for it to have stood easily on its hind legs, like other predator dinosaurs; instead, it ambled on all four legs.

    “It does add significantly to the strangeness,” said Matthew C. Lamanna, a paleontologist at the Carnegie Museum of Natural History in Pittsburgh, who was not involved with the research. He described the evidence for Spinosaurus’s semiaquatic existence as “quite convincing.”

    model
    A life-size model of Spinosaurus aegyptiacus made from polystyrene, resin and steel. The model was created from computer scans of fossils, images of lost bones and educated guesses using bones from related dinosaurs. Credit Mike Hettwer/National Geographic

    An exhibition on Spinosaurus opens Friday at the National Geographic Museum in Washington. The National Geographic Society provided financing for the research.

    The new findings may return prominence to Ernst Stromer, the German paleontologist who first described Spinosaurus aegyptiacus, meaning “Egyptian spine lizard.”

    Stromer’s fossil, mounted in the Bavarian State Collection of Paleontology in Munich, included the lower jaw and parts of the spine.

    In April 1944, the British Royal Air Force dropped a bomb on the museum, and Spinosaurus — and every Egyptian dinosaur fossil known at the time — burned.

    After that, some isolated bones of Spinosaurus were found, but nothing as complete as Stromer’s specimen. Some evidence, like the conical teeth, suggested Spinosaurus ate fish, but perhaps it just waded into a river and caught them like a grizzly bear.

    One fossil, uncovered in Morocco around 1975, had been thought to be part of the lower jaw of a crocodile, but a decade ago, Cristiano Dal Sasso of the Milan museum realized that interpretation was upside down. “There were too many bones to be the lower jaw,” he said.

    It was actually from the top half of a snout of a huge adult Spinosaurus.

    In 2008, an Italian geologist showed the new Spinosaurus bones to Dr. Dal Sasso, who then showed them to Dr. Ibrahim.

    But the scientists were missing crucial geological information about where the bones had been excavated.

    Dr. Ibrahim needed to find the nomad, so last year, he returned to the Erfoud area.

    A researcher helping him, Samir Zouhri, of University Hassan II Casablanca, asked how they would locate the man, whether Dr. Ibrahim had a name or an address or a phone number.

    “I didn’t want to disappoint my Moroccan colleague,” Dr. Ibrahim said, “so I told him I distinctly remember that the man had a mustache.”

    Dr. Zouhri did not seem impressed. “He basically thought that was not an adequate starting point for our wild-goose chase,” Dr. Ibrahim said.

    The search indeed proved fruitless, and they were sitting in a cafe, about to give up, when a mustachioed man walked past.

    It was the nomad who had showed Dr. Ibrahim the Spinosaurus bones five years earlier.

    “I had to run, because he was walking fast,” Dr. Ibrahim said. “He recognized me, and I convinced him to take us to the site.”

    The nomad, who Dr. Ibrahim said did not want public attention, remains anonymous.

    A few months later, Dr. Ibrahim and other members of the research team returned, uncovering more bone fragments and confirming that the fossils Dr. Ibrahim had seen in 2008 and those in Milan were all from the same dinosaur.

    The partial skeleton — about a quarter to a third of the animal, Dr. Sereno estimated — did not tell the whole story. The researchers made a three-dimensional digital model of the bones and added pieces scanned from other fossils like the Milan snout and the Stromer drawings.

    The new fossil also served as a Rosetta stone. A second dinosaur fossil of Stromer’s turned out to be a Spinosaurus; some of its bones matched those from the Moroccan find.

    Putting all the pieces together and making educated guesses from close relatives of Spinosaurus, the researchers came up with a complete skeleton and produced a life-size model for the National Geographic exhibition.

    The dearth of swimming dinosaurs has been something of a mystery. Among other groups of animals, some species did move from land to water — for instance, the mammals that evolved into whales. Even among birds, the modern-day descendants of dinosaurs, some like penguins and ducks spend copious time in the water.

    “Dinosaurs were landlubbers,” Dr. Sereno said. “Until this one.”

    See the full article here.

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  • richardmitnick 12:46 pm on September 3, 2014 Permalink | Reply
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    From Dennis Overbye at The New York Times: “The V838 Monocerotis Star Still Has Astronomers’ Heads Exploding” 

    New York Times

    The New York Times

    SEPT. 3, 2014
    Dennis Overbye

    For astronomers and aficionados of cosmic violence, an obscure star known as V838 Monocerotis has turned out to be a gift that has kept on giving for a long, long time.

    http://upload.wikimedia.org/wikipedia/commons/thumb/d/d3/V838_Mon_HST.jpg/600px-V838_Mon_HST.jpg838
    In January 2002, a dull star in an obscure constellation suddenly became 600,000 times more luminous than our Sun, temporarily making it the brightest star in our Milky Way galaxy. The mysterious star, called V838 Monocerotis, has long since faded back to obscurity. But observations by NASA’s Hubble Space Telescope of a phenomenon called a “light echo” around the star have uncovered remarkable new features. These details promise to provide astronomers with a CAT-scan-like probe of the three-dimensional structure of shells of dust surrounding an aging star.

    NASA Hubble Telescope
    NASA/ESA Hubble

    The star forms part of the shoulder of an imagined unicorn in the constellation Monoceros, 20,000 light-years away, and in January 2002, astronomers saw it blow up. Over the next few months, it became a million times as luminous as the sun and swelled in diameter to a billion miles, comparable to the orbit of Jupiter. It was briefly one of the most luminous stars in the galaxy.

    Astronomers are still arguing and speculating about what happened. Measurements of the star’s light output showed that the explosion happened in three stages, flaring and then dimming three times from January to March 2002.

    Some scientists have suggested that V 838 swallowed planets in its orbit. Others have proposed that V 838 was actually two stars orbiting each other, and that the explosions were a result of their atmospheres merging into a common envelope of gas.

    The answer could be relevant to our plight. Someday, a few billion years from now, the sun will run out of fuel and become a red giant,swallowing Mercury and frying the Earth and Venus.

    Whatever it was that made V 838 erupt, astronomers are still watching it go.

    The star, it turns out, is embedded in a cloud of dust trillions of miles across. Most likely, astronomers say, these wreaths of dust gave rise to V 838 perhaps four million years ago. They would usually be invisible, but the pulses of light traveling outward from the explosion have illuminated shells of dust previously kicked off the star. The Hubble Space Telescope has recorded images of these so-called light echoes, and viewing them in succession calls to mind the explosion of Darth Vader’s Death Star — except that in this case, nothing is moving but the outward-rushing light wave; the dust is standing still.

    As a result, the death of V 838 Monocerotis is giving astronomers a rare look at the circumstances that gave it birth. Dust to dust and ashes to ashes. So it goes.

    Nothing lasts forever, but in the universe, nothing is ever really gone, either. As the Columbia University astrophysicist Caleb Scharf pointed out in an essay on his blog recently, long after you and I are dead, the light reflected off our faces today will still be traveling across space, ever fainter with distance, but always there. For somebody with a big enough telescope somewhere, we will be immortal.

    See the full article here.

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  • richardmitnick 3:06 pm on August 28, 2014 Permalink | Reply
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    From The New York Times: “Parasites Practicing Mind Control” 

    New York Times

    The New York Times

    AUG. 28, 2014
    Carl Zimmer

    An unassuming single-celled organism called Toxoplasma gondii is one of the most successful parasites on Earth, infecting an estimated 11 percent of Americans and perhaps half of all people worldwide. It’s just as prevalent in many other species of mammals and birds. In a recent study in Ohio, scientists found the parasite in three-quarters of the white-tailed deer they studied.

    One reason for Toxoplasma’s success is its ability to manipulate its hosts. The parasite can influence their behavior, so much so that hosts can put themselves at risk of death. Scientists first discovered this strange mind control in the 1990s, but it’s been hard to figure out how they manage it. Now a new study suggests that Toxoplasma can turn its host’s genes on and off — and it’s possible other parasites use this strategy, too.

    image
    A microscopic cyst in the brain of a mouse containing thousands of Toxoplasma gondii parasites. New research has found that the parasite is able to exert a form of mind control by turning its host’s genes on and off. Credit Jitender P. Dubey/U.S.D.A.

    Toxoplasma manipulates its hosts to complete its life cycle. Although it can infect any mammal or bird, it can reproduce only inside of a cat. The parasites produce cysts that get passed out of the cat with its feces; once in the soil, the cysts infect new hosts.

    Toxoplasma returns to cats via their prey. But a host like a rat has evolved to avoid cats as much as possible, taking evasive action from the very moment it smells feline odor.

    Experiments on rats and mice have shown that Toxoplasma alters their response to cat smells. Many infected rodents lose their natural fear of the scent. Some even seem to be attracted to it.

    Manipulating the behavior of a host is a fairly common strategy among parasites, but it’s hard to fathom how they manage it. A rat’s response to cat odor, for example, emerges from complex networks of neurons that detect an odor, figure out its source and decide on the right response in a given moment.

    Within each of the neurons in those networks, thousands of genes are producing proteins and other molecules essential for relaying all of the necessary information throughout the body. Simple Toxoplasma seems ill-equipped to take over such a complicated system.

    But a new study published in the journal Molecular Ecology hints that the parasite can do so by relying on an eerily elegant strategy. Think of the genes in a host as keys on a piano. Toxoplasma, it seems, simply plays some of the keys differently to produce a new melody.

    A rat is made up of lots of different kinds of cells, from the neurons in its brain to the bone-producing cells in its skeleton to the insulin-making cells in its pancreas. Yet all of them carry the same 20,000 genes. Depending on the function of a particular cell, some of its genes are switched on and others are shut down.

    Genes may be switched off, or silenced, by the attachment of molecular caps called methyl groups, a process called methylation. In order to switch a gene on again, the caps are removed.

    Methylation does more than just allow cells to develop into a variety of organs. It lets them change the way they work in response to signals from the outside. In the brain, for example, neurons rely on this process to lay down long-term memories and change how an animal responds to its environment.

    Ajai Vyas, a neurobiologist at Nanyang Technological University in Singapore, wondered if Toxoplasma might wreak changes on rats by changing methylation in the rat brain — an idea “just hiding in plain sight,” he said.

    In earlier research, Dr. Vyas and his colleagues had found that infected rats produced extra amounts of a neurotransmitter called arginine vasopressin. The neurotransmitter is manufactured by a small set of neurons buried in a structure of the brain called the medial amygdala.

    Perhaps, Dr. Vyas thought, the parasite switched on the gene for arginine vasopressin in those cells. To find out, he and his colleagues ran a series of tests.

    First they looked at the gene for arginine vasopressin in the medial amygdala of rats. In infected rats, they found, many of the molecular caps were missing, suggesting that Toxoplasma had “unsilenced” the gene in order to increase production of the neurotransmitter. The arginine vasopressin then might alter their response to cats.

    If that were true, Dr. Vyas reasoned, then counteracting the parasite’s strategy should change the rat’s behavior.

    He and his colleagues injected an extra supply of the molecular caps into infected rats. Some of the caps attached to the arginine vasopressin gene, and the rats became more fearful of the odor of cats.

    That experiment led Dr. Vyas to see if he could make the rats behave as if they were being controlled by parasites — but without the parasites.

    He and his colleagues removed molecular caps from the arginine vasopressin gene, mimicking what Toxoplasma might be doing to its hosts. The rats became reckless, feeling no fear at the whiff of cats.

    “The animals looked like they were infected, even though there was no parasite around,” said Dr. Vyas.

    “I think they could be on to something interesting,” said Michael Eisen, a biologist at the University of California, Berkeley, who has researched Toxoplasma in mice and was not involved in the new study. But he thought more experiments would have to be done to make a compelling case that the parasites really are using methylation to control their hosts.

    Kami Kim of Albert Einstein College of Medicine, who also was not involved in the study, was more enthusiastic about the research. She also suggested that the strategy may be not be uncommon. In a review published this spring in the American Journal of Pathology, Dr. Kim and her colleagues survey a number of species that may use methylation to turn host genes on and off.

    The bacteria that cause leprosy, for example, invade certain kinds of neurons and change some of their molecular caps. This methylation causes the neurons to change into stem cells much like those in an embryo. In this new state, the infected cells leave the nervous system and migrate through the body, spreading the bacteria with them.

    “It looks like it will be a general strategy used by pathogens,” said Dr. Kim.

    See the full article here.

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  • richardmitnick 2:42 pm on August 24, 2014 Permalink | Reply
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    From The New York Times: “Methane Is Discovered Seeping From Seafloor Off East Coast, Scientists Say” 

    New York Times

    The New York Times

    AUG. 24, 2014
    HENRY FOUNTAIN

    Scientists have discovered methane gas bubbling from the seafloor in an unexpected place: off the East Coast of the United States where the continental shelf meets the deeper Atlantic Ocean.

    seeps
    Methane bubbles flow in small streams out of the sediment on an area of seafloor offshore Virginia north of Washington Canyon.

    The methane is emanating from at least 570 locations, called seeps, from near Cape Hatteras, N.C., to the Georges Bank southeast of Nantucket, Mass. While the seepage is widespread, the researchers estimated that the amount of gas was tiny compared with the amount released from all sources each year.

    In a paper published online Sunday in the journal Nature Geoscience, the scientists, including Adam Skarke of Mississippi State University and Carolyn Ruppel of the United States Geological Survey, reported evidence that the seepage had been going on for at least 1,000 years.

    They said the depths of the seeps suggested that in most cases the gas did not reach the atmosphere but rather dissolved in the ocean, where it could affect the acidity of the water, at least locally.

    But methane is a potent, if relatively short-lived, greenhouse gas, so the discovery should aid the study of an issue of concern to climate scientists: the potential for the release of huge stores of methane on land and under the seas as warming of the atmosphere and oceans continues.

    “It highlights a really key area where we can test some of the more radical hypotheses about climate change,” said John Kessler, a professor at the University of Rochester who was not involved in the research.

    Methane seeps occur in many places, but usually in areas that are tectonically active, like off the West Coast of the United States, or connect to deep petroleum basins, as in the Gulf of Mexico. The Atlantic margin, as the region where the shelf meets the deeper oceanic crust is known, is tectonically quiet, and most of the seeps are not thought to be linked to oil and gas deposits.

    “This is a large amount of methane seepage in an area we didn’t expect,” Dr. Skarke said. “That raises new questions for us.”

    Dr. Ruppel said that at about 40 of the seeps — those in water depths exceeding 3,300 feet — the methane may be migrating up through the sediments from deeper reservoirs of the gas. Further studies would be needed to confirm this, she said.

    If the gas is found to be originating from reservoirs, then oil companies could potentially be interested in determining whether the reservoirs can be tapped.

    But Dr. Ruppel said most of the seeps had been found in depths of about 800 to 2,000 feet, where the methane, which is produced by microbes, is most likely trapped in sediments near the seafloor , within cagelike molecules of ice called hydrates. Natural variability in water temperatures, caused by ocean circulation and other factors, may be warming these hydrates just enough to release the gas.

    Hydrates at such relatively shallow depths “are exquisitely sensitive to small changes in temperature,” she said. “You don’t have to change things very much to get the methane to come out.”

    Dr. Kessler, author of an article reviewing the findings in the same journal, said that because the Atlantic margin was unaffected by tectonic activity or other factors, it should prove to be a convenient location to conduct long-term studies of links between climate change and methane releases.

    “How will those release rates accelerate as bottom temperature warms, or how will they decelerate if there are some cooling events?” Dr. Kessler said. “We don’t really have all of the answers. But this is a great place to try to find them.”

    See the full article here.

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  • richardmitnick 2:57 pm on August 19, 2014 Permalink | Reply
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    From The New York Times: “The Intelligent-Life Lottery” 

    New York Times

    The New York Times

    AUG. 18, 2014
    George Johnson

    Almost 20 years ago, in the pages of an obscure publication called Bioastronomy News, two giants in the world of science argued over whether SETI — the Search for Extraterrestrial Intelligence — had a chance of succeeding. Carl Sagan, as eloquent as ever, gave his standard answer. With billions of stars in our galaxy, there must be other civilizations capable of transmitting electromagnetic waves. By scouring the sky with radio telescopes, we just might intercept a signal.

    But Sagan’s opponent, the great evolutionary biologist Ernst Mayr, thought the chances were close to zero. Against Sagan’s stellar billions, he posed his own astronomical numbers: Of the billions of species that have lived and died since life began, only one — Homo sapiens — had developed a science, a technology, and the curiosity to explore the stars. And that took about 3.5 billion years of evolution. High intelligence, Mayr concluded, must be extremely rare, here or anywhere. Earth’s most abundant life form is unicellular slime.

    Since the debate with Sagan, more than 1,700 planets have been discovered beyond the solar system — 700 just this year. Astronomers recently estimated that one of every five sunlike stars in the Milky Way might be orbited by a world capable of supporting some kind of life.

    That is about 40 billion potential habitats. But Mayr, who died in 2005 at the age of 100, probably wouldn’t have been impressed. By his reckoning, the odds would still be very low for anything much beyond slime worlds. No evidence has yet emerged to prove him wrong.

    Maybe we’re just not looking hard enough. Since SETI began in the early 1960s, it has struggled for the money it takes to monitor even a fraction of the sky. In an online essay for The Conversation last week, Seth Shostak, the senior astronomer at the SETI Institute, lamented how little has been allocated for the quest — just a fraction of NASA’s budget.

    “If you don’t ante up,” he wrote, “you will never win the jackpot. And that is a question of will.”

    Three years ago, SETI’s Allen Telescope Array in Northern California ran out of money and was closed for a while. Earlier this month, it was threatened by wildfire — another reminder of the precariousness of the search.

    Allen Telescope Array
    Allen Telescope Array

    It has been more than 3.5 billion years since the first simple cells arose, and it took another billion years or so for some of them to evolve and join symbiotically into primitive multicellular organisms. These biochemical hives, through random mutations and the blind explorations of evolution, eventually led to creatures with the ability to remember, to anticipate and — at least in the case of humans — to wonder what it is all about.

    Every step was a matter of happenstance, like the arbitrary combination of numbers — 3, 12, 31, 34, 51 and 24 — that qualified a Powerball winner for a $90 million prize this month. Some unknowing soul happened to enter a convenience store in Rifle, Colo., and — maybe with change from buying gasoline or a microwaved burrito — purchase a ticket just as the machine was about to spit out those particular numbers.

    According to the Powerball website, the chance of winning the grand prize is about one in 175 million. The emergence of humanlike intelligence, as Mayr saw it, was about as likely as if a Powerball winner kept buying tickets and — round after round — hit a bigger jackpot each time. One unlikelihood is piled on another, yielding a vanishingly rare event.

    In one of my favorite books, “Wonderful Life,” Stephen Jay Gould celebrated what he saw as the unlikelihood of our existence. Going further than Mayr, he ventured that if a slithering creature called Pikaia gracilens had not survived the Cambrian extinction, about half a billion years ago, the entire phylum called Chordata, which includes us vertebrates, might never have existed.

    Gould took his title from the Frank Capra movie in which George Bailey gets to see what the world might have been like without him — idyllic Bedford Falls is replaced by a bleak, Dickensian Pottersville.

    For Gould, the fact that any of our ancestral species might easily have been nipped in the bud should fill us “with a new kind of amazement” and “a frisson for the improbability of the event” — a fellow agnostic’s version of an epiphany.

    “We came this close (put your thumb about a millimeter away from your index finger), thousands and thousands of times, to erasure by the veering of history down another sensible channel,” he wrote. “Replay the tape a million times,” he proposed, “and I doubt that anything like Homo sapiens would ever evolve again. It is, indeed, a wonderful life.”

    Other biologists have disputed Gould’s conclusion. In the course of evolution, eyes and multicellularity arose independently a number of times. So why not vertebrae, spinal cords and brains? The more bags of tricks an organism has at its disposal, the greater its survival power may be. A biological arms race ensues, with complexity ratcheted ever higher.

    But those occasions are rare. Most organisms, as Daniel Dennett put it in “Darwin’s Dangerous Idea,” seem to have “hit upon a relatively simple solution to life’s problems at the outset and, having nailed it a billion years ago, have had nothing much to do in the way of design work ever since.” Our appreciation of complexity, he wrote, “may well be just an aesthetic preference.”

    In Five Billion Years of Solitude, by Lee Billings, published last year, the author visited Frank Drake, one of the SETI pioneers.

    “Right now, there could well be messages from the stars flying right through this room,” Dr. Drake told him. “Through you and me. And if we had the right receiver set up properly, we could detect them. I still get chills thinking about it.”

    He knew the odds of tuning in — at just the right frequency at the right place and time — were slim. But that just meant we needed to expand the search.

    “We’ve been playing the lottery only using a few tickets,” he said.

    See the full article here.

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  • richardmitnick 7:50 am on August 14, 2014 Permalink | Reply
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    From The New York Times: “Our Microbiome May Be Looking Out for Itself” 

    New York Times

    The New York Times

    AUG. 14, 2014
    Carl Zimmer

    Your body is home to about 100 trillion bacteria and other microbes, collectively known as your microbiome. Naturalists first became aware of our invisible lodgers in the 1600s, but it wasn’t until the past few years that we’ve become really familiar with them.

    This recent research has given the microbiome a cuddly kind of fame. We’ve come to appreciate how beneficial our microbes are — breaking down our food, fighting off infections and nurturing our immune system. It’s a lovely, invisible garden we should be tending for our own well-being.

    microbe
    A highly magnified view of Enterococcus faecalis, a bacterium that lives in the human gut. Microbes may affect our cravings, new research suggests. Credit Centers for Disease Control and Prevention

    But in the journal Bioessays, a team of scientists has raised a creepier possibility. Perhaps our menagerie of germs is also influencing our behavior in order to advance its own evolutionary success — giving us cravings for certain foods, for example.

    Maybe the microbiome is our puppet master.

    “One of the ways we started thinking about this was in a crime-novel perspective,” said Carlo C. Maley, an evolutionary biologist at the University of California, San Francisco, and a co-author of the new paper. What are the means, motives and opportunity for the microbes to manipulate us? They have all three.

    The idea that a simple organism could control a complex animal may sound like science fiction. In fact, there are many well-documented examples of parasites controlling their hosts.

    Some species of fungi, for example, infiltrate the brains of ants and coax them to climb plants and clamp onto the underside of leaves. The fungi then sprout out of the ants and send spores showering onto uninfected ants below.

    How parasites control their hosts remains mysterious. But it looks as if they release molecules that directly or indirectly can influence their brains.

    Our microbiome has the biochemical potential to do the same thing. In our guts, bacteria make some of the same chemicals that our neurons use to communicate with one another, such as dopamine and serotonin. And the microbes can deliver these neurological molecules to the dense web of nerve endings that line the gastrointestinal tract.

    A number of recent studies have shown that gut bacteria can use these signals to alter the biochemistry of the brain. Compared with ordinary mice, those raised free of germs behave differently in a number of ways. They are more anxious, for example, and have impaired memory.

    Adding certain species of bacteria to a normal mouse’s microbiome can reveal other ways in which they can influence behavior. Some bacteria lower stress levels in the mouse. When scientists sever the nerve relaying signals from the gut to the brain, this stress-reducing effect disappears.

    Some experiments suggest that bacteria also can influence the way their hosts eat. Germ-free mice develop more receptors for sweet flavors in their intestines, for example. They also prefer to drink sweeter drinks than normal mice do.

    Scientists have also found that bacteria can alter levels of hormones that govern appetite in mice.

    Dr. Maley and his colleagues argue that our eating habits create a strong motive for microbes to manipulate us. “From the microbe’s perspective, what we eat is a matter of life and death,” Dr. Maley said.

    Different species of microbes thrive on different kinds of food. If they can prompt us to eat more of the food they depend on, they can multiply.

    Microbial manipulations might fill in some of the puzzling holes in our understandings about food cravings, Dr. Maley said. Scientists have tried to explain food cravings as the body’s way to build up a supply of nutrients after deprivation, or as addictions, much like those for drugs like tobacco and cocaine.

    But both explanations fall short. Take chocolate: Many people crave it fiercely, but it isn’t an essential nutrient. And chocolate doesn’t drive people to increase their dose to get the same high. “You don’t need more chocolate at every sitting to enjoy it,” Dr. Maley said.

    Perhaps, he suggests, the certain kinds of bacteria that thrive on chocolate are coaxing us to feed them.

    John F. Cryan, a neuroscientist at University College Cork in Ireland who was not involved in the new study, suggested that microbes might also manipulate us in ways that benefited both them and us. “It’s probably not a simple parasitic scenario,” he said.

    Research by Dr. Cryan and others suggests that a healthy microbiome helps mammals develop socially. Germ-free mice, for example, tend to avoid contact with other mice.

    That social bonding is good for the mammals. But it may also be good for the bacteria.

    “When mammals are in social groups, they’re more likely to pass on microbes from one to the other,” Dr. Cryan said.

    “I think it’s a very interesting and compelling idea,” said Rob Knight, a microbiologist at the University of Colorado, who was also not involved in the new study.

    If microbes do in fact manipulate us, Dr. Knight said, we might be able to manipulate them for our own benefit — for example, by eating yogurt laced with bacteria that would make use crave healthy foods.

    “It would obviously be of tremendous practical importance,” Dr. Knight said. But he warned that research on the microbiome’s effects on behavior was “still in its early stages.”

    The most important thing to do now, Dr. Knight and other scientists said, was to run experiments to see if microbes really are manipulating us.

    Mark Lyte, a microbiologist at the Texas Tech University Health Sciences Center who pioneered this line of research in the 1990s, is now conducting some of those experiments. He’s investigating whether particular species of bacteria can change the preferences mice have for certain foods.

    “This is not a for-sure thing,” Dr. Lyte said. “It needs scientific, hard-core demonstration.”

    See the full article here.

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  • richardmitnick 4:43 pm on July 21, 2014 Permalink | Reply
    Tags: , , , , , , New York Times   

    From The New York Times: “More Eyes on the Skies” 

    New York Times

    The New York Times

    JULY 21, 2014

    do
    DENNIS OVERBYE

    The future, it is often said, belongs to those who plan for it. And astronomers have been busy working the proverbial smoke-filled rooms (or whatever passes for them today) where the destiny of big science is often shaped and crisscrossing one another in airports on fund-raising trips. Now they are about to have something to show for it.

    More than a decade after competing groups set out to raise money for gargantuan telescopes that could study planets around distant stars and tune into the birth of galaxies at the dawn of time, shovels, pickaxes and more sophisticated tools are now about to go to work on mountaintops in Hawaii and Chile in what is going to be the greatest, most expensive and ambitious spree of telescope-making in the history of astronomy.

    If it all plays out as expected and budgeted, astronomers of the 2020s will be swimming in petabytes of data streaming from space and the ground. Herewith a report card on the future of big-time stargazing.

    On June 20, officials from the European Southern Observatory blew the top off a mountain in northern Chile called Armazones, breaking ground for what is planned to be the largest, most powerful optical telescope ever built. Known as the European Extremely Large Telescope, or E-ELT, it will have a segmented mirror 39 meters (about 128 feet) in diameter, powerful enough to see planets around distant stars. By comparison, the largest telescopes now operating are 10 meters in diameter.

    ESO E-ELT
    ESO’s E-ELT

    ESO VLT Interferometer
    The European Southern Observatory consortium’s Very Large Telescope array, in Chile, is made up of four eight-meter telescopes. Credit European Southern Observatory

    The European Southern Observatory is a consortium of 14 European nations and Brazil, which has agreed to join but is still waiting for its Parliament to ratify the move. Brazil’s official entrance would put the group more than 90 percent of the way toward the $1.5 billion in 2012 dollars the telescope is projected to cost, enough to begin big-ticket items like a dome, said Lars Christensen, a spokesman for the consortium.

    The telescope should be ready on June 19, 2024. “We’ll all be back here,” said Tim de Zeeuw, the group’s director general, at the groundbreaking.

    That’s not the only mega telescope project out there. Two years ago, another group of astronomers blasted away the top of another mountain in Chile, Las Campanas, where they plan to build the Giant Magellan Telescope.

    Giant Magellan Telescope
    Giant Magellan Telescope

    That telescope will have at its heart a set of seven eight-meter mirrors ganged together to make the equivalent of a mirror 25 meters in diameter. Three of those mirrors have been cast and polished at the University of Arizona, one of nine institutions that make up the Giant Magellan organization. A fourth mirror is on order for next year.

    Giant Magellan
    Australia Astronomy Limited
    Australian National University
    Carnegie Institution for Science
    Harvard University
    Korean Astronomy and Space Science Institute
    Harvard-Smithsonian Center for Astrophysics
    Texas A&M University
    University of Arizona
    University of Chicago
    University of Texas at Austin

    Wendy Freedman, the director of the Carnegie Observatories, one of the spearheads of the Magellan collaboration, said by email that members were now in the final phases of forming a limited liability corporation, the legal and financial entity that will build and own the telescope. To date, the group has raised about $500 million of the $880 million (2012 dollars) needed for their telescope.

    She expects construction to begin later this year. “Our plan is to be on the air with the first four mirrors taking early science data in 2021,” she said. “So things are continuing to go very well.”

    In Hawaii, there will be no blasting needed, just some grading with a bulldozer, on Mauna Kea, where yet another group of astronomers plans to build a telescope 30 meters in diameter — the simply named Thirty Meter Telescope — on a plateau just below the nearly 14,000-foot summit. Mauna Kea, the highest peak in the Pacific, is already home to 12 telescopes, including the twin 10-meter telescopes at the Keck observatory and a pair of eight-meters, making it the busiest mountain in astronomy.

    Thirty Meter Telescope
    Thirty Meter Telescope

    Thirty Meter Telescope
    Association of Canadian Universities for Research in Astronomy
    California Institute of Technology
    Department of Science and Technology of India
    National Astronomical Observatories of the Chinese Academy of Sciences
    National Astronomical Observatory of Japan
    University of California

    It is also a sacred place for Hawaiians, many of whose ancestors have been buried up there. As a result, it’s not so easy gaining permission to add yet another telescope, said Michael Bolte of the University of California, Santa Cruz, a co-director of the project, an international collaboration led by Caltech and the University of California and now doing business as Thirty Meter Telescope International Observatory LLC.

    A billion-dollar telescope capable of outperforming Hubble can’t be built by a backyard stargazer or even a single university. The Thirty Meter Telescope in Hawaii and the Giant Magellan in Chile, both now on the verge of construction, are the products of international teams that have pursued their dreams even through a global recession.

    “I think we’re finally free and clear to build on that site,” Dr. Bolte said in an interview, saying they had chosen an unobtrusive spot for the telescope. He expects to begin grading a road to the site this summer as soon as the project clears its last hurdle with the Hawaiian authorities.

    The Thirty Meter Telescope will cost $1.2 billion in those same 2012 dollars. By early next year, when India and Canada are expected to become full members of the corporation, Dr. Bolte said, they will have 85 percent of the money needed; they are still looking for more partners. A grand groundbreaking ceremony is being scheduled for Oct. 7.

    “It’s a crazy science,” Dr. Bolte said, ticking off the names of historical benefactors of astronomy and telescope financiers, “that facilities at the forefront tend to be built with private money,” something that rarely happens in, say, physics.

    Big Mirrors, Big Views

    The view from these new telescopes, astronomers say, should be spectacular.

    A telescope’s ability to gather light is determined by the area of its primary mirror. For a long time, the five-meter Hale reflector on Palomar Mountain, in San Diego County, was considered the practical earthly limit, but in the 1980s, astronomers devised ways to build bigger, thinner, mirrors that would not sag, leading to a bevy of eight-meter mirrors as well as the two 10-meter Kecks. The Magellan, the smallest of the new breed, however, will be six times as powerful as the Kecks in scooping up distant dim starlight; the others will be even more powerful.

    Caltech Hale Telescope at Palomar
    Hale Telescope

    Keck Observatory
    Keck Observatory

    The Hubble Space Telescope is only 94 inches, about 2.4 meters in diameter. It gains its power not from size but from being above the atmosphere, which blurs and filters the light from stars.

    NASA Hubble Telescope
    NASA/ESA Hubble

    Increasing their powers even more, the new telescopes will be equipped with a technology that did not exist the last time around: adaptive optics [in use since the 1990's], the ability to adjust the shape of the mirrors to minimize or cancel the effects of the atmospheric turbulence that causes stars to twinkle. The result, astronomers say, is that these telescopes will be able to detect fainter objects than Hubble can, like planets or bits of galaxies coming together, and more clearly.

    A Boom in Chile

    The inauguration of these new telescopes, early in the next decade, will further enshrine the Atacama Desert in Chile, which is bone-dry, high, dark and blessed with remarkably steady air, as the center of world astronomy. The region already is home to, among other observatories, the Atacama Large Millimeter/sub-millimeter Array, or ALMA, an international project that is the world’s most expensive radio telescope, and the European Southern Observatory’s Very Large Telescope, an array of four eight-meter telescopes near the site of the coming Extremely Large Telescope.

    ALMA Array
    ALMA

    The whole neighborhood, in fact, is booming. But for red tape, construction was also supposed to have started this month on the Large Synoptic Survey Telescope on Pachón Mountain, in, yes, Chile.

    LSST Telescope
    LSST

    That telescope, a joint project of the National Science Foundation and the Department of Energy, is eight meters in diameter. That mountain was dynamited back in 2011. The project director, Steve Kahn of Stanford, said that a news release was already written and waiting for the moment when the project, officially the LSST Corporation, receives formal approval from the National Science Foundation to start spending money.

    “I am sure we will get started officially soon, but unfortunately, this process isn’t over until it is over,” Dr. Kahn wrote in an email.

    A ceremony for laying the “first stone” is planned for next spring in Chile, he said.

    The National Science Foundation has budgeted $473 million to build the telescope. The Energy Department is kicking in $165 million for a 3,200-megapixel camera, which will produce an image of the entire sky every few days and over 10 years will produce a movie of the universe, swamping astronomers with data that will enable them to spot everything that moves or blinks in the heavens, including asteroids and supernova explosions.

    Among the Stars

    What about outer space, where the stars actually are?

    It was front-page news two years ago when the National Reconnaissance Office, which operates spy satellites, gave NASA two space telescopes the same size and design as a Hubble that had been sitting in a warehouse. Some astronomers, notably the former astronaut and Hubble repairman John M. Grunsfeld, NASA’s associate administrator for science mission, suggested that one of these could be used to jump-start a mission to study dark energy.

    The National Academy of Sciences had ranked that mission atop the to-do list for this decade, but it was ambushed by the rising cost of NASA’s James Webb Space Telescope (more on that later).

    NASA Webb Telescope
    NASA/Webb

    A committee from the academy has recently endorsed the idea of using the spy telescope, which is 2.4 meters in diameter, for the mission, instead of the originally envisioned one-meter telescope. The academy agreed that the bigger telescope would enhance the scientific returns of the mission, now known as Wfirst-AFTA, for Wide Field Infrared Survey Telescope-Astrophysics Focused Telescope Assets, but warned that it could increase the cost and complexity. Congress directed NASA to spend $56 million on the mission in the last fiscal year, 2014, and the proposed budget for 2015 includes about $14 million.

    NASA WFIRST telescope
    NASA/WFIRST

    If this keeps up, said David Spergel, an astronomer at Princeton who is involved with the academy and the telescope, the mission could start as early as 2023, near the time the European Space Agency will send up its own dark energy probe, known as Euclid. By then, he said, the mission’s name would probably be less of a mouthful. “The good thing about Wfirst-AFTA,” Dr. Spergel wrote in an email, “is that there is no way that we will keep that name.”

    ESA Euclid
    ESA/Euclid

    Among the possibilities that NASA is studying closely is adding a coronagraph to the telescope [WFIRST]. Coronagraphs are basically opaque disks that were invented to black the intense light from the sun so astronomers could study the feathery faint corona of hot gases streaming outward from it. Exoplanet hunters are eager to deploy them to look for planets around distant stars. Getting a coronagraph on the dark energy telescope would be a valuable step toward a future mission, once known as the Terrestrial Planet Finder and now known by the placeholder name of New Worlds Telescope, long a dream of exoplanet hunters, that would be able to study Earthlike planets for signs of habitability, weather and life.

    And then there is the most expensive and high-flying “big eye” of all, NASA’s James Webb Space Telescope, which Nature magazine once called “the telescope that ate astronomy.” Named for a former administrator of NASA, it is the successor to Hubble (which is still going strong, thank you), but is almost three times its size, with a 6.5-meter-diameter mirror that will have to fold out like a flower in orbit.

    The Webb telescope was supposed to be launched this year, but was late and burned past its $5 billion budget like one of NASA’s rockets, devouring money that could have gone toward other projects. The House Appropriations Committee once voted to cancel it, but the project was reinstated with a budget cap of $8 billion and a launch date of 2018.

    Since then, no news has basically been good news for Webb. It is still on track for 2018, NASA says. In July the agency reported that it had finished testing the framework that will hold the leaves of the telescope mirror and scientific instruments in place.

    Heat and Light

    The Webb telescope was built to study the first stars and galaxies that emerged in the hundred million years or so after the Big Bang, a missing period in cosmic history. It is therefore designed to record infrared radiation rather than visible light because objects at that distance and vintage are flying away from us so fast, by the rules of the expanding universe, that their light has been “redshifted” to longer wavelengths.

    As it happens, infrared, or heat radiation, is an excellent way to study planets, which tend to emit more heat than light. Astronomers have long hoped that spectroscopic observations of an exoplanet atmosphere might reveal the signatures of life, such as oxygen or chlorophyll.

    Recently, some astronomers have suggested they might even be able to see industrial pollution as well, in particular chlorofluorocarbons, the greenhouse gases that also destroy ozone. Over a few millenniums of industry, the thinking goes, some of these gases could build up to levels detectable from far away and stay that way for 50,000 years.

    It would be ominous, however, Henry W. Lin, a student at Harvard, and his colleagues wrote in a paper submitted to The Monthly Notices of the Royal Astronomical Society, if astronomers see the markers of pollution around some distant planet but no indications of present life. That detection, they wrote, “might serve as an additional warning to the ‘intelligent’ life here on Earth about the risks of industrial pollution.” The future belongs to those who plan and care for it.

    Last but hardly least is the Hubble Space Telescope, which has been providing humanity with matchless cosmic postcards from its perch above the sky ever since it was launched in 1990 and first fixed in 1993. Hubble was last visited and serviced by astronauts — presumably for the final time — in 2009. Matt Mountain, the director of the Space Telescope Science Institute, reports that it is doing well. A recent NASA review concluded, he said in an email, that “Hubble is operating at or near the highest level of performance and scientific productivity in its history.”

    Recent estimates of its orbit suggest that it will re-enter Earth’s atmosphere no earlier than 2027 and may probably stay up well into the 2030s. Its main instruments are likely to still be working in 2020. That means the Hubble will still be operational when the Webb telescope goes up in 2018.

    “It looks like it,” Dr. Mountain said. “We are certainly setting our planning that way.”

    See the full article here.

    [The condition of Hubble not withstanding, any cancellation of Webb would be about as stupid and wrong headed as was the cancellation of the Superconducting_Super_Collider by the idiots in our Congress in 1993. Look where that got us: jobs as the hand maidens of the European Organization for Nuclear Research, CERN, which built the Large Hadron Collider and found what Fermilab's Tevatron had searched a very long time to find, the Higgs boson. We could just cede space to the ESA for spacecraft and sit with our large collection of ground based monsters.]


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  • richardmitnick 11:17 am on July 16, 2014 Permalink | Reply
    Tags: , , , , , New York Times, Universe   

    From The New York Times: "Stalking the Shadow Universe" 

    New York Times

    JULY 16, 2014
    DENNIS OVERBYE

    For centuries people have found meaning — or thought they did — in what they could see in the sky, the shapes of the constellations echoing old myths, the sudden feathery intrusion of comets, the regular dances of the planets, the chains of galaxies, spanning unfathomable distances of time and space.

    Universe

    Since the 1980s, however, astronomers have been forced to confront the possibility that most of the universe is invisible, and that all the glittering chains of galaxies are no more substantial, no more reliable guides to physical reality, than greasepaint on the face of a clown.

    The brute mathematical truth is that atoms, the stuff of stars, you and me, make up only 5 percent of the universe by weight. A quarter of it is made of mysterious particles known as dark matter, and the remaining 70 percent a mysterious form of energy called dark energy. Physicists theorize that dark matter could be exotic particles left over from the Big Bang. They don’t know what it is, but they can deduce that dark matter is there by its gravitational effect on the things they can see. If [Isaac] Newton’s laws of gravity held over cosmic distances, huge amounts of more matter than we can see were needed to provide the gravitational glue to keep clusters of galaxies from flying apart, and to keep the stars swirling around in galaxies at high speed.

    Cosmologists have theorized that it is in fact dark matter, slowly congealing under its own weight into vast clouds, that provides the scaffolding for stars and galaxies.

    To strip the greasepaint from cosmic history, astronomers have performed computer simulations of how dark matter would evolve from a nearly uniform cloud into the filaments and clumps characteristic of the arrangement of galaxies today in the luminous universe. A multinational group led by Mark Vogelsberger of the Massachusetts Institute of Technology has recently performed one of the most detailed of these studies yet, a calculation called Illustris.

    Their model sought to take into account not just the gravity of dark matter particles pulling atoms and one another around, but the electromagnetic and nuclear interactions between atoms — so-called gastrophysics — like the formation and explosion of stars.

    The result, they said, is the closest match yet between dark matter models and the distribution and types of galaxies in the visible universe.

    Meanwhile, astronomers at the California Institute of Technology have begun to be able to illuminate and map the weblike structure of the dark matter in space using an instrument they call the Cosmic Web Imager on the 200-inch telescope at Palomar Observatory. The imager in effect uses bright galaxies and quasars as a kind of flashlight to light up the sparse atoms strewn along with the dark matter in space, confirming the tendril structure predicted by the computer simulations.

    Caltech Cosmic Web Imager
    Cosmic Web Imager

    Caltech Palomar Observatory
    Palomar Observatory – Caltech

    qua
    Quasar

    More evidence of the power of the dark side.


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  • richardmitnick 5:37 am on July 8, 2014 Permalink | Reply
    Tags: , , , , New York Times   

    From The New York Times: “Earthlike Planets May Be Merely an Illusion” 

    New York Times

    The New York Times

    JULY 7, 2014
    DOUGLAS QUENQUA

    In 2010, astronomers were stirred by the discovery of Gliese 581g, a distant Earthlike planet that orbited its star just closely enough to allow for surface water, and possibly life.

    gliese

    But the planet’s existence was almost immediately called into question, with some researchers unable to locate it. Now, a team at Penn State is saying that Gliese 581g and a presumed neighbor planet, Gliese 581d, were simply illusions caused by the star they supposedly orbited.

    By measuring hydrogen atoms in the atmosphere of that star (Gliese 581), the researchers found that signals originally thought to be coming from planets were actually false positives caused by intense stellar magnetic activity, like sunspots. Such activity can sometimes stimulate the emission of hydrogen.

    gliese 581
    Gliese 581
    Digital Sky Survey / ESO

    But all is not lost, said the study’s lead author, Paul Robertson, an astronomer at Penn State. Correcting for the magnetic activity also increased the signals for other planets long thought to orbit Gliese 581.

    “We found evidence for stellar noise in the data that has been published previously, and when we corrected for that, we got this really nice dichotomy,” he said. “The real planets and their signals get much stronger, but these planets d and g, their signals disappeared.” Though their findings, which were published in the journal Science, may represent the end of the road for Gliese 581g, it could yield a useful new method for identifying planets.

    “I’m hoping that this will provide a nice resolution to the dispute,” Dr. Robertson said.

    See the full article here


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  • richardmitnick 5:03 am on June 3, 2014 Permalink | Reply
    Tags: , , , , New York Times,   

    From Dennis Overbye at the New York Times: “A Star-Gazing Palace’s Hazy Future” 

    New York Times

    The New York Times

    Dennis Overbye

    JUNE 2, 2014

    This is copyright protected, so just a glimpse.

    James Lick, a piano manufacturer and land baron in 19th-century California, wanted to build himself a pyramid, but a friend persuaded him to leave his money to science. And so it came to be that Lick was buried under a telescope on Mount Hamilton, 30 miles south of San Francisco.

    It was there that the University of California, fueled by his $700,000 bequest, founded Lick Observatory, the first of the great mountaintop outposts that would make California the center of 20th-century astronomy.

    UCO Lick Observatory

    But this is the 21st century. Last year the university served notice that it planned to spin off Lick in order to concentrate its resources on bigger telescopes in Hawaii, including a $1.2 billion the Thirty-Meter Telescope that is to be built by an international collaboration by the end of the decade. It has launched Lick on a “glide path” to self-sufficiency by 2018.

    Thirty Meter Telescope

    There has been no peace in the California heavens since. The plan, part of a general retrenchment and budget flattening, has set off something like a civil war among California astronomers — “brother against brother,” in the words of Alex Filippenko of the University of California, Berkeley. They fear the move could lead to the closing of the venerable observatory, a valuable research and educational tool for students and faculty, and undermine the university’s longtime leadership in astronomy. “Other astronomers are quaking in their boots,” Dr. Filippenko said.

    See the full article here


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