1. cozydark:

    Why is the Universe Dominated by Matter, Not Anti-Matter? |

    A collaboration with major participation by physicists at the University of Wisconsin-Madison has made a precise measurement of elusive, nearly massless particles, and obtained a crucial hint as to why the universe is dominated by matter, not by its close relative, anti-matter.

    The particles, called anti-neutrinos, were detected at the underground Daya Bay experiment, located near a nuclear reactor in China, 55 kilometers north of Hong Kong. For the measurement of anti-neutrinos it made in 2012, the Daya Bay collaboration has been named runner-up for breakthrough of the year from Science magazine.

    Anti-particles are almost identical twins of sub-atomic particles (electrons, protons and neutrons) that make up our world. When an electron encounters an anti-electron, for example, both are annihilated in a burst of energy. Failure to see these bursts in the universe tells physicists that anti-matter is vanishingly rare, and that matter rules the roost in today’s universe.

    “At the beginning of time, in the Big Bang, a soup of particles and anti-particles was created, but somehow an imbalance came about,” says Karsten Heeger, a professor of physics at UW-Madison. “All the studies that have been done have not found enough difference between particles and anti-particles to explain the dominance of matter over anti-matter.”

    But the neutrino, an extremely abundant but almost massless particle, may have the right properties, and may even be its own anti-particle, Heeger says. “And that’s why physicists have put their last hope on the neutrino to explain the absence of anti-matter in the universe.”

    Heeger and his group at UW-Madison have been responsible for much of the design and development of the anti-neutrino detectors at Daya Bay. Jeff Cherwinka, from the university’s Physical Sciences Laboratory in Stoughton, Wis. is chief engineer of the experiment and has overseen much of the detector assembly and installation. The construction of the experiment was completed this fall and data-taking started in October using the full set of anti-neutrino detectors. continue reading

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    biocanvas:

A 1000-times confocal view of a sea urchin embryo undergoing metaphase, the point in cell division where chromosomes are aligned in a single line.
Image by Dr. John Henson, Dickinson College.

    biocanvas:

    A 1000-times confocal view of a sea urchin embryo undergoing metaphase, the point in cell division where chromosomes are aligned in a single line.

    Image by Dr. John Henson, Dickinson College.

    (via biocanvas)

  3. text
    dailyfossil:

Mei 
When: Early Cretaceous (~125 million years) 
Where: Liaoning, China
What: Mei is a paravian dinosaur. Paraves is the clade comprised of birds and two families of non-avian dinsaurs; Troodontidae and Dromaeosauridae. As Mei is a fairly basal member of the troodontids, it is not very far removed from the common ancestor of all paravians. Its bird-like heritage can be easily seen in this extraordinary articulated fossil shown above. This specimen was found in a sleeping pose, which is very much like the resting posture of many modern birds, with the legs folded underneath the body and the head folded back and resting on the shoulder.  It is this pose that gives the taxon its full name:  Mei long, which translates to ‘sleeping dragon’. This animal is a sub-adult, determined via the ends of its bones not yet being fused, and would be roughly 21 inches (~53 cm) long, if it was not curled up as it is.  
 The find of a basal troodontid in this pose gives us far more information than just when the sleeping posture was adapted by this clade. It has been determined that modern birds commonly sleep like this to preserve their body heat, covering up the areas that are most prone to radiating heat. If Mei long  and its kin were not ‘warm blooded’ than there would be no benefit to sleeping in this pose. Thus, this provides another compelling bit of evidence that the ‘warm bloodedness’ of modern birds was present in their mesozoic non-avian relatives. 

    dailyfossil:

    Mei 

    When: Early Cretaceous (~125 million years) 

    Where: Liaoning, China

    What: Mei is a paravian dinosaur. Paraves is the clade comprised of birds and two families of non-avian dinsaurs; Troodontidae and Dromaeosauridae. As Mei is a fairly basal member of the troodontids, it is not very far removed from the common ancestor of all paravians. Its bird-like heritage can be easily seen in this extraordinary articulated fossil shown above. This specimen was found in a sleeping pose, which is very much like the resting posture of many modern birds, with the legs folded underneath the body and the head folded back and resting on the shoulder.  It is this pose that gives the taxon its full name:  Mei long, which translates to ‘sleeping dragon’. This animal is a sub-adult, determined via the ends of its bones not yet being fused, and would be roughly 21 inches (~53 cm) long, if it was not curled up as it is.  

     The find of a basal troodontid in this pose gives us far more information than just when the sleeping posture was adapted by this clade. It has been determined that modern birds commonly sleep like this to preserve their body heat, covering up the areas that are most prone to radiating heat. If Mei long  and its kin were not ‘warm blooded’ than there would be no benefit to sleeping in this pose. Thus, this provides another compelling bit of evidence that the ‘warm bloodedness’ of modern birds was present in their mesozoic non-avian relatives. 

    (via scinerds)

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