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Permalink Reply by doone on June 14, 2012 at 6:50am

The Immune System Family Tree

Jun. 14, 2012

Permalink Reply by doone on June 14, 2012 at 8:56am

Cassini sees tropical lakes on Saturns moon Titan

http://www.sciencedaily.com/releases/2012/06/120614083559.htm

June 14, 2012

ScienceDaily (June 14, 2012) — NASA's Cassini spacecraft has spied long-standing methane lakes, or puddles, in the "tropics" of Saturn's moon Titan. One of the tropical lakes appears to be about half the size of Utah's Great Salt Lake, with a depth of at least 3 feet (1 meter).

The result, which is a new analysis of Cassini data, is unexpected because models had assumed the long-standing bodies of liquid would only exist at the poles. The findings appear in this week's issue of the journal Nature.

Where could the liquid for these lakes come from? "A likely supplier is an underground aquifer," said Caitlin Griffith, the paper's lead author and a Cassini team associate at the University of Arizona, Tucson. "In essence, Titan may have oases."

Understanding how lakes or wetlands form on Titan helps scientists learn about the moon's weather. Like Earth's hydrological cycle, Titan has a "methane" cycle, with methane rather than water circulating. In Titan's atmosphere, ultraviolet light breaks apart methane, initiating a chain of complicated organic chemical reactions. But existing models haven't been able to account for the abundant supply of methane.

"An aquifer could explain one of the puzzling questions about the existence of methane, which is continually depleted," Griffith said. "Methane is a progenitor of Titan's organic chemistry, which likely produces interesting molecules like amino acids, the building blocks of life."

Global circulation models of Titan have theorized that liquid methane in the moon's equatorial region evaporates and is carried by wind to the north and south poles, where cooler temperatures cause methane to condense. When it falls to the surface, it forms the polar lakes. On Earth, water is similarly transported by the circulation, yet the oceans also transport water, thereby countering the atmospheric effects.

The latest results come from Cassini's visual and infrared mapping spectrometer, which detected the dark areas in the tropical region known as Shangri-La, near the spot where the European Space Agency's Huygens probe landed in 2005. When Huygens landed, the heat of the probe's lamp vaporized some methane from the ground, indicating it had landed in a damp area.

Areas appear dark to the visual and infrared mapping spectrometer when liquid ethane or methane are present. Some regions could be shallow, ankle-deep puddles. Cassini's radar mapper has seen lakes in the polar region, but hasn't detected any lakes at low latitudes.

The tropical lakes detected by the visual and infrared mapping spectrometer have remained since 2004. Only once has rain been detected falling and evaporating in the equatorial regions, and only during the recent expected rainy season. Scientists therefore deduce the lakes could not be substantively replenished by rain.

"We had thought that Titan simply had extensive dunes at the equator and lakes at the poles, but now we know that Titan is more complex than we previously thought," said Linda Spilker, the Cassini project scientist based at NASA's Jet Propulsion Laboratory, Pasadena, Calif. "Cassini still has multiple opportunities to fly by this moon going forward, so we can't wait to see how the details of this story fill out."

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. NASA's Jet Propulsion Laboratory manages the mission for NASA's Science Mission Directorate, Washington. The visual and infrared mapping spectrometer team is based at the University of Arizona, Tucson.

For more information, visit http://www.nasa.gov/cassiniandhttp://saturn.jpl.nasa.gov .

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The above story is reprinted from materials provided by NASA/Jet Propulsion Laboratory.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.

Journal Reference:

1. Caitlin A. Griffith, Juan M. Lora, Jake Turner, Paulo F. Penteado, Robert H. Brown, Martin G. Tomasko, Lyn Doose, Charles See.Possible tropical lakes on Titan from observations of dark terrain. Nature, 2012; 486 (7402): 237 DOI:10.1038/nature11165

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Permalink Reply by doone on June 14, 2012 at 8:57am

Where humans split from sharks: Common ancestor comes into focus

http://www.sciencedaily.com/releases/2012/06/120613133032.htm

June 14, 2012

ScienceDaily (June 13, 2012) — The common ancestor of all jawed vertebrates on Earth resembled a shark, according to a new analysis of the braincase of a 290-million-year-old fossil fish that has long puzzled paleontologists.

New research on Acanthodes bronni, a fish from the Paleozoic era, sheds light on the evolution of the earliest jawed vertebrates and offers a new glimpse of the last common ancestor before the split between the earliest sharks and the first bony fishes -- the lineage that would eventually include human beings.

"Unexpectedly, Acanthodes turns out to be the best view we have of conditions in the last common ancestor of bony fishes and sharks," said Michael Coates, PhD, professor of organismal biology and anatomy at the University of Chicago and senior author of the study published in Nature. "Our work is telling us that the earliest bony fishes looked pretty much like sharks, and not vice versa. What we might think of as shark space is, in fact, general modern jawed vertebrate space."

The group gnathostomes, meaning "jaw-mouths," includes tens of thousands of living vertebrate species, ranging from fish and sharks to birds, reptiles, mammals and humans. Cartilaginous fish, which today include sharks, rays, and ratfish, diverged from the bony fishes more than 420 million years ago. But little is known about what the last common ancestor of humans, manta rays and great white sharks looked like.

Coates and colleagues Samuel Davis and John Finarelli found answers to this mystery in an unexpected place: the acanthodians, extinct fishes that generally left behind only tiny scales and elaborate suites of fin spines. But armed with new data on what the earliest sharks and bony fishes looked like, Coates and colleagues re-examined fossils of Acanthodes bronni, the best-preserved acanthodian species.

Davis created highly detailed latex molds of specimens revealing the inside and outside of the skull, providing a valuable new data set for assessing cranial and jaw anatomy as well as the organizations of sensory, circulatory and respiratory systems in the species.

"We want to explore braincases if possible, because they are exceptionally rich sources of anatomical information," Coates said. "They're much better than scales, teeth or fin spines, which, on their own, tend to deliver a confusing signal of evolutionary relationships."

The analysis of the sample combined with recent CT scans of skulls from early sharks and bony fishes led the researchers to a surprising reassessment of what Acanthodes bronni tells us about the history of jawed vertebrates.

"For the first time, we could look inside the head of Acanthodes, and describe it within this whole new context," Coates said. "The more we looked at it, the more similarities we found with sharks."

However, analysis of the evolutionary relationships of Acanthodes bronni -- even with these new data added -- still connected this species to early bony fishes. Meanwhile, some acanthodian species turned out to be primitive sharks, while others were relatives of the common ancestor of sharks and bony fishes.

This result explains some of the longstanding confusion about the placement of acanthodians in vertebrate history. But additional analyses went a step further. Using more than 100 morphological characters, the researchers quantified the mutual resemblance among the earliest jawed fishes. Acanthodians as a whole, including the earliest members of humans' own deep evolutionary past, appear to cluster with ancient sharks.

"The common ancestors of all jawed vertebrates today organized their heads in a way that resembled sharks," said Finarelli, PhD, Lecturer in Vertebrate Biology at University College Dublin. "Given what we now know about the interrelatedness of early fishes, these results tell us that while sharks retained these features, bony fishes moved away from such conditions."

Furthermore, the analysis demonstrated that all of these early members of the modern gnathostomes are clearly separated from what now appear to be the most primitive vertebrates with jaws: a collection of armored fishes called placoderms.

"There appears to be a fundamental distinction between the placoderms and all other vertebrates with jaws," Finarelli said.

This new revision of the lineage of early jawed vertebrates will allow paleontologists to dig into deeper mysteries, including how the body plan of these ancient species transformed over the transition from jawless to jawed fishes.

"It helps to answer the basic question of what's primitive about a shark." Coates said. "And, at last, we're getting a better handle on primitive conditions for jawed vertebrates as a whole."

"This study is an example of the power of phylogenetics combined with the comparative morphology of living and fossil organisms," said Maureen Kearney, program director in National Science Foundation's Division of Environmental Biology, which co-funded the research. "It shows us important evolutionary transitions in the history of life, providing a new window into the sequence of evolutionary changes during early vertebrate evolution."

The study, "Acanthodes and shark-like conditions in the last common ancestor of modern gnathostomes," will be published on June 14 by Nature. The research was also funded by the Natural Environment Research Council.

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The above story is reprinted from materials provided by University of Chicago Medical Center, via Newswise.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.

Journal Reference:

1. Samuel P. Davis, John A. Finarelli, Michael I. Coates. Acanthodes and shark-like conditions in the last common ancestor of modern gnathostomes. Nature, 2012; 486 (7402): 247 DOI: 10.1038/nature11080

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Permalink Reply by doone on June 15, 2012 at 7:01am

Another view of the 99 percent

SLAVOJ ŽIŽEK: 'HUMANITY IS OK, BUT 99% OF PEOPLE ARE BORING IDIOTS'

From The Guardian:

If you have read all of Žižek's work, you are doing better than me. Born in 1949, the Slovenian philosopher and cultural critic grew up under Tito in the former Yugoslavia, where suspicions of dissidence consigned him to academic backwaters. He came to western attention in 1989 with his first book written in English,The Sublime Object of Ideology, a re-reading of Žižek's great hero Hegel through the perspective of another hero, the psychoanalyst Jacques Lacan. Since then there have been titles such as Living in the End Times, along with films – The Pervert's Guide To Cinema – and more articles than I can count. By the standards of cultural theory, Žižek sits at the more accessible end of the spectrum – but to give you an idea of where that still leaves him, here's a typical quote from a book called Žižek: A Guide for the Perplexed, intended to render him more comprehensible: "Žižek finds the place for Lacan in Hegel by seeing the Real as the correlate of the self-division and self-doubling within phenomena." At the risk of upsetting Žižek's fanatical global following, I would say that a lot of his work is impenetrable. But he writes with exhilarating ambition and his central thesis offers a perspective even his critics would have to concede is thought-provoking. In essence, he argues that nothing is ever what it appears, and contradiction is encoded in almost everything. Most of what we think of as radical or subversive – or even simply ethical – doesn't actually change anything. "Like when you buy an organic apple, you're doing it for ideological reasons, it makes you feel good: 'I'm doing something for Mother Earth,' and so on. But in what sense are we engaged? It's a false engagement. Paradoxically, we do these things to avoid really doing things. It makes you feel good. You recycle, you send £5 a month to some Somali orphan, and you did your duty." But really, we've been tricked into operating safety valves that allow the status quo to survive unchallenged? "Yes, exactly." The obsession of western liberals with identity politics only distracts from class struggle, and while Žižek doesn't defend any version of communism ever seen in practice, he remains what he calls a "complicated Marxist" with revolutionary ideals.

To his critics, as one memorably put it, he is the Borat of philosophy, churning out ever more outrageous statements for scandalous effect."The problem with Hitler was that he was not violent enough," for example, or "I am not human. I am a monster." Some dismiss him as a silly controversialist; others fear him as an agitator for neo-Marxist totalitarianism. But since the financial crisis he has been elevated to the status of a global-recession celebrity, drawing crowds of adoring followers who revere him as an intellectual genius. His popularity is just the sort of paradox Žižek delights in because if it were down to him, he says, he would rather not talk to anyone.

More here.

Posted by Azra Raza at 06:44 AM | Permalink 

Permalink Reply by doone on June 15, 2012 at 6:49pm

by WeberShandwick. Browse more infographics.

Permalink Reply by doone on June 16, 2012 at 9:55am

NEUROSCIENCE: THE MIND READER

David Cyranoski in Nature:

Adrian Owen still gets animated when he talks about patient 23. The patient was only 24 years old when his life was devastated by a car accident. Alive but unresponsive, he had been languishing in what neurologists refer to as a vegetative state for five years, when Owen, a neuro-scientist then at the University of Cambridge, UK, and his colleagues at the University of Liège in Belgium, put him into a functional magnetic resonance imaging (fMRI) machine and started asking him questions.

Incredibly, he provided answers. A change in blood flow to certain parts of the man's injured brain convinced Owen that patient 23 was conscious and able to communicate. It was the first time that anyone had exchanged information with someone in a vegetative state.

Patients in these states have emerged from a coma and seem awake. Some parts of their brains function, and they may be able to grind their teeth, grimace or make random eye movements. They also have sleep–wake cycles. But they show no awareness of their surroundings, and doctors have assumed that the parts of the brain needed for cognition, perception, memory and intention are fundamentally damaged. They are usually written off as lost.

Owen's discovery¹, reported in 2010, caused a media furore.

More here.

Posted by Abbas Raza at 03:04 AM | Permalink

Permalink Reply by doone on June 16, 2012 at 1:50pm

Neutrons escaping to a parallel world?

http://www.sciencedaily.com/releases/2012/06/120615104347.htm

June 16, 2012

ScienceDaily (June 15, 2012) — In a paper recently published in European Physical Journal (EPJ) C, researchers hypothesised the existence of mirror particles to explain the anomalous loss of neutrons observed experimentally. The existence of such mirror matter had been suggested in various scientific contexts some time ago, including the search for suitable dark matter candidates.

Theoretical physicists Zurab Berezhiani and Fabrizio Nesti from the University of l'Aquila, Italy, reanalysed the experimental data obtained by the research group of Anatoly Serebrov at the Institut Laue-Langevin, France. It showed that the loss rate of very slow free neutrons appeared to depend on the direction and strength of the magnetic field applied. This anomaly could not be explained by known physics.

Berezhiani believes it could be interpreted in the light of a hypothetical parallel world consisting of mirror particles. Each neutron would have the ability to transition into its invisible mirror twin, and back, oscillating from one world to the other. The probability of such a transition happening was predicted to be sensitive to the presence of magnetic fields, and could therefore be detected experimentally.

This neutron-mirror-neutron oscillation could occur within a timescale of a few seconds, according to the paper. The possibility of such a fast disappearance of neutrons -- much faster than the ten-minute long neutron decay -- albeit surprising, could not be excluded by existing experimental and astrophysical limits.

This interpretation is subject to the condition that the earth possesses a mirror magnetic field on the order of 0.1 Gauss. Such a field could be induced by mirror particles floating around in the galaxy as dark matter. Hypothetically, the earth could capture the mirror matter via some feeble interactions between ordinary particles and those from parallel worlds.

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The above story is reprinted from materials provided by Springer, via EurekAlert!, a service of AAAS.

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Journal Reference:

1. Zurab Berezhiani, Fabrizio Nesti. Magnetic anomaly in UCN trapping: signal for neutron oscillations to parallel world? The European Physical Journal C, 2012; 72 (4) DOI: 10.1140/epjc/s10052-012-1974-5

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Permalink Reply by Michel on June 16, 2012 at 2:43pm

@doone - Great article on the Mind Reader.
A must read if you're into consciousness.

Permalink Reply by archaeopteryx on June 16, 2012 at 4:45pm

I've always felt consciousness was highly overrated.

Permalink Reply by doone on June 16, 2012 at 7:03pm

IAN HACKING ON THE STRUCTURE OF SCIENTIFIC REVOLUTIONS: 50TH ANNIVERSARY EDITION

An excerpt from Ian Hacking's introduction to the new edition of Thomas S. Kuhn's The Structure of Scientific Revolutions, in the LA Review of Books:

ONE THING IS NOT SAID often enough: Thomas S. Kuhn's The Structure of Scientific Revolutions, like all great books, is a work of passion, and a passionate desire to get things right. This is plain even from its modest first sentence: "History, if viewed as a repository for more than anecdote or chronology, could produce a decisive transformation in the image of science by which we are now possessed." Thomas Kuhn was out to change our understanding of the sciences — that is, of the activities that have enabled our species, for better or worse, to dominate the planet. He succeeded.

1962

The present edition commemorates the fiftieth anniversary of The Structure of Scientific Revolutions. Nineteen sixty-two was a long time ago. The sciences themselves have radically changed. The queen of the sciences, then, was physics. Kuhn had been trained as a physicist. Few people knew much physics, but everybody knew that physics was where the action was. A cold war was in progress, so everyone knew about the Bomb. American schoolchildren had to practice cowering under their desks. At least once a year towns sounded an air raid siren, at which everyone had to take shelter. Those who protested against a nuclear weapon, by ostentatiously not taking shelter, could be arrested, and some were. Bob Dylan first performed "A Hard Rain's A-Gonna Fall" in September 1962; everyone assumed it was about nuclear fallout. In October 1962 there was the Cuban Missile Crisis, the closest the world has come, after 1945, to nuclear war. Physics and its threat were on everyone's mind.

The Cold War is long over, and physics is no longer where the action is. Another event of 1962 was the awarding of Nobel prizes to Francis Crick and James Watson for the molecular biology of DNA and to Max Perutz and John Kendrew for the molecular biology of hemoglobin. That was the harbinger of change. Today, biotechnology rules. Kuhn took physical science and its history as his model. You will have to decide, after reading his book, about the extent to which what he said about the physical sciences holds true in the teeming, present world of biotechnology. Add in information science. Add in what the computer has done to the practice of science. Even experiment is not what it was, for it has been modified and to a certain extent replaced by computer simulation. And everyone knows that the computer has changed communication. In 1962 scientific results were announced at meetings, in special seminars, in preprints, and then in articles published in specialist journals. Today the primary mode of publication is in an electronic archive.

There is yet another fundamental difference between 2012 and 1962. It affects the heart of the book, fundamental physics. In 1962 there were competing cosmologies: steady state and big bang, two completely different pictures of the universe and its origin.

Posted by Robin Varghese at 02:18 AM | Permalink

Permalink Reply by doone on June 17, 2012 at 12:23am

Whale population size, dynamics determined based on ancient DNA

http://www.sciencedaily.com/releases/2012/05/120509180044.htm

June 17, 2012

ScienceDaily (May 9, 2012) — Estimates of whale population size based on genetics versus historical records diverge greatly, making it difficult to fully understand the ecological implications of the large-scale commercial whaling of the 19th and early 20th centuries, but a comparison of DNA samples from modern and prehistoric gray whales supports the idea that the population was substantially larger pre-whaling and saw a sharp, recent decrease that is consistent with whaling as the cause.

The full results are reported May 9 in the open access journal PLoS ONE.

Previous estimates of pre-whaling population size in gray whales using historic records and census modeling suggest there used to be about 15,000 to 35,500 eastern Pacific gray whales. In contrast, estimates from genetic data suggest a much higher original population size of about 78,000 to 116,000 individuals. This discrepancy, though, could be explained by a pre-whaling decrease in population. The authors of the current study, led by Elizabeth Alter of City University of New York (York College), set out to test this hypothesis.

They isolated DNA from whale bones excavated from archaeological sites, ranging from about 150 to 2,500 years old. By comparing these sequences with sequences from modern whales, they determined that a severe decline in whale population occurred recently, suggesting that the original population size was indeed larger than estimated based on historical record and arguing against population decline caused by any pre-whaling forces.

"Retrieving DNA from ancient whales allows more direct insights into their population histories than using modern DNA alone. In this case, we were able to look at pre-whaling specimens of gray whales, and found that the genetic data are consistent with a sharp and recent bottleneck -- very likely the result of commercial whaling. As methods for retrieval and analysis of ancient DNA improve, we'll be able to increasingly refine population histories for heavily exploited species like whales."

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The above story is reprinted from materials provided by Public Library of Science.

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Journal Reference:

1. S. Elizabeth Alter, Seth D. Newsome, Stephen R. Palumbi. Pre-Whaling Genetic Diversity and Population Ecology in Eastern Pacific Gray Whales: Insights from Ancient DNA and Stable Isotopes. PLoS ONE, 2012; 7 (5): e35039 DOI:10.1371/journal.pone.0035039

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Permalink Reply by doone on June 17, 2012 at 5:45pm

How Did That Non-Polar Bear Get Up There?

Jun. 17, 2012

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