Science & TechnologyS


Wolf

New form of animal communication discovered

1 of the most commonly studied animals may shed light on how the brain controls social interactions.

Sniffing, a common behavior in dogs, cats and other animals, has been observed to also serve as a method for rats to communicate - a fundamental discovery that may help scientists identify brain regions critical for interpreting communications cues and what brain malfunctions may cause some complex social disorders.

Researchers have long observed how animals vigorously sniff when they interact, a habit usually passed off as simply smelling each other. But Daniel W. Wesson, PhD, of Case Western Reserve University School of Medicine, whose research is published in Current Biology, found that rats sniff each other to signal a social hierarchy and prevent aggressive behavior.

Wesson, who drew upon previous work showing that, similar to humans, rodents naturally form complex social hierarchies, used wireless methods to record and observe rats as they interacted. He found that, when two rats approach each other, one communicates dominance by sniffing more frequently, while the subordinate signals its role by sniffing less. Wesson found that if the subordinate didn't do so, the dominant rat was more likely to become aggressive to the other.

Info

Stanford psychologists uncover brain-imaging inaccuracies

fMRI
© L.A. Cicero
Pictures of brain regions "activating" are by now a familiar accompaniment to any neurological news story. With functional magnetic resonance imaging, or fMRI, you can see specific brain regions light up, standing out against the background like night owls' apartment windows.

It's easy to forget that these brain images aren't real snapshots of brain activity. Instead, each picture is the result of many layers of analysis and interpretation, far removed from raw data.

"It's just one representation of brain activity," said Matthew Sacchet, a PhD student in the Neurosciences Program at the Stanford School of Medicine. "As you process the data, it can change."

Sacchet works in the lab of Stanford psychology Associate Professor Brian Knutson, who studies reward processing in a small area of the brain known as the nucleus accumbens. Precisely how that structure activates is at the heart of an ongoing debate about reward circuits - a subject that holds relevance for our understanding of everything from addiction to financial risk-taking.

Unfortunately, according to a paper from Knutson and Sacchet, hundreds of research papers on this circuit may be unintentionally biased. When the labs processed their fMRI findings, many used a one-size-fits-all strategy that skewed which regions of the brain appeared to be activating.

"I honestly think most people want good data," said Knutson. "I'm excited that we can make this kind of research more rigorous."

The paper appeared in the journal NeuroImage.

Sun

Solar cycle update: Twin peaks?

Something unexpected is happening on the sun. 2013 is supposed to be the year of Solar Max, the peak of the 11-year sunspot cycle. Yet 2013 has arrived and solar activity is relatively low. Sunspot numbers are well below their values in 2011, and strong solar flares have been infrequent for many months.

The quiet has led some observers to wonder if forecasters missed the mark. Solar physicist Dean Pesnell of the Goddard Space Flight Center has a different explanation:
"This is solar maximum," he suggests. "But it looks different from what we expected because it is double peaked."

Bomb

Some brain cells are better virus fighters

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© Hyelim ChoThe white arrows highlight infected cells in a mouse brain. Scientists at Washington University School of Medicine in St. Louis have discovered that genetic programming makes some brain cells more resistant to infection.
Viruses often spread through the brain in patchwork patterns, infecting some cells but missing others. New research at Washington University School of Medicine in St. Louis helps explain why. The scientists showed that natural immune defenses that resist viral infection are turned on in some brain cells but switched off in others.

"The cells that a pathogen infects can be a major determinant of the seriousness of brain infections," says senior author Michael Diamond, MD, PhD, professor of medicine. "To understand the basis of disease, it is important to understand which brain regions are more susceptible and why."

While some brain infections are caused by bacteria, fungi or parasites, often the cause is a virus, such as West Nile virus, herpesvirus or enteroviruses.

For their study, now available online in Nature Medicine, the researchers focused on granule cell neurons, a cell type that rarely becomes infected. They compared gene profiles in granule cells from the cerebellum with the activity in cortical neurons in the cerebral cortex, which are more vulnerable to infection.

The comparison revealed many differences, including a number of genes in cortical neurons that were less well-expressed - meaning that for those specific genes there were fewer copies of mRNA, the molecules that relay genetic information from DNA to the cell's protein-making mechanisms.

Telescope

Rare 'Zodiacal Light' will be visible in night sky soon

The solar system's small bodies have been often in the news lately. There are currently two bright comets in the southern sky, one of which, Comet C/2011 L4 (PANSTARRS) will soon be moving into the northern sky. An asteroid named 2012 DA14 recently passed close to the Earth. There have been two bright meteors in the past month, one in Russia and one in California. But these types of bodies aren't the smallest relics of the solar system visible from here on Earth. A rare and hard to spot phenomenon called the Zodiacal Light, made from tiny solar system dust particles, can only be sighted under the best conditions. And a good time to view it is coming up soon.
Image
© European Southern Observatory/Flickr

Cassiopaea

Discovery of rare supernova has some astronomers pondering their premises

Supernova
© X-ray: NASA/CXC/Rutgers/G.Cassam-Chenaï, J.Hughes et al.; Radio: NRAO/AUI/NSF/GBT/VLA/Dyer, Maddalena & Cornwell; Optical: Middlebury College/F.Winkler, NOAO/AURA/NSF/CTIO Schmidt & DSS
Astronomers have long been aware of supernovae - brilliant explosions ejecting massive amounts of gas and energy into the surrounding medium. But occasionally one of them is different, set apart, unlike anything we have seen before.

Researchers with the Harvard-Smithsonian Center for Astrophysics (CfA) have announced in a new paper that one such event has been discovered.

Supernovae are split into sub-types. While some of them can be traced to the collapse of massive stars, others arise from the accretion of mass onto a tiny white dwarf, barely more massive than our Sun, yet far more dense. The exact manner in which the supernova proceeds can further subdivide supernovae into different classes.

One of the rarest classes is known as Type Ibn. Only five previous events have ever been seen and they were all found in galaxies similar to the Milky Way - young spiral systems with significant ongoing star formation.

The working theory is that such supernovae are the result of the collapse of massive stars that had ejected massive amounts of helium prior to their collapse. The catch is such high mass stars - those on the order of 100 solar masses - do not live very long. Because of the immense gravitational pressure on their cores, the rate of fusion needed to sustain hydrostatic equilibrium is immense and they quickly burn through their nuclear fuel.

Info

We are all "related" to Romans, Vikings, Egyptians & Attila the Hun

Tree
© Sense About Science
Scientists warn the public that commercial DNA tests are 'genetic astrology'.

Genetics researchers say that commercial DNA tests cannot provide accurate stories about personal ancestry. Part of a rapidly growing market for genealogy, commercial 'genetic ancestry tests' offer people a profile of their genetic history based on a DNA sample for around £200. The test findings tell people that they have links to groups such as Aboriginals or Vikings, to particular migrations of people and sometimes to famous figures such as Napoleon or Cleopatra. But the researchers warn that such histories are either so general as to be personally meaningless or they are just speculation from thin evidence.

They are issuing their warning alongside a public guide, published today: Sense About Genetic Ancestry Testing, where they explain why DNA tests are used in population research and why they do not provide accurate information about an individual's ancestry:
  • Our individual ancestry is much shallower than people might imagine - the best estimate is that the most recent person from whom everyone alive today is descended lived just 3,500 years ago.
  • As we look back through time we quickly accumulate more ancestors than we have sections of DNA, which means we have ancestors from whom we have inherited no DNA.
  • There are millions of possible 'stories' of your ancestry. To know whether any one of them is likely to be true, it would need to be tested statistically for its likelihood against other possibilities.
  • The genetic ancestry business uses a phenomenon well-known in other areas such as horoscopes, where general information is interpreted as being more personal than it really is.

Fireball 5

Russian asteroid explosion and past impactors paint a potentially grim future for Earth

Impact Events
© MasPix/deviantartAn artist’s sketch of asteroids striking the Earth 65 million years ago during the reign of the Dinosaurs. Humanity will face potentially dangerous impactors, both large and small, from space in the (distant/near?) future. It is inevitable.
The recent meteor explosion over Chelyabinsk brought to the forefront a topic that has worried astronomers for years, namely that an impactor from space could cause widespread human fatalities. Indeed, the thousand+ injured recently in Russia was a wake-up call. Should humanity be worried about impactors? "Hell yes!" replied astronomer Neil deGrasse Tyson to CNN's F. Zakharia .

The geological and biological records attest to the fact that some impactors have played a major role in altering the evolution of life on Earth, particularly when the underlying terrestrial material at the impact site contains large amounts of carbonates and sulphates. The dating of certain large impact craters (50 km and greater) found on Earth have matched events such as the extinction of the Dinosaurs (Hildebrand 1993, however see also G. Keller's alternative hypothesis). Ironically, one could argue that humanity owes its emergence in part to the impactor that killed the Dinosaurs.

Comment: The Apocalypse: Comets, Asteroids and Cyclical Catastrophes,

Comets and the Horns of Moses


Galaxy

Astronomers measure distance to nearest galaxy

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© ESA/NASA/Hubble
Astronomers determined that the LMC lies 163,000 light-years away.

Astronomers have measured the distance to our nearest neighbor galaxy, according to a news release from the Carnegie Institution for Science. In the process of refining the measurement of the distance to the nearest galaxy, astronomers were able to enhance the astronomical calculation that helps measure the expansion rate of the universe.

According to NASA, the expansion or contraction of the universe is contingent on its content and past history. The current rate of expansion is typically expressed as the Hubble constant. The Carnegie Institution adds that the Hubble constant is named after 20th Century Carnegie astronomer Edwin P. Hubble, who discovered that the universe has been expanding since its beginning.

In order to determine the age and size of our universe, scientists must identify the rate of this continuing growth. According to astronomers, one of the biggest uncertainties when it came to past measurement of the Hubble constant has been the distance to the Large Magellanic Cloud, which just so happens to be our nearest neighbor galaxy.

To determine the scale of the universe, astronomers must first measure the distance to close-by objects and then using observations of these objects in more distant galaxies to calculate distance ever further out in the universe. Without an accurate measurement of the distance to the LMC, however, scientists have had trouble pinpointing the distances to more distant objects.

Magnify

Russian scientists discover unidentified bacteria in sub-glacial Lake Vostok

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© Reuters / Alexey EkaikinVostock research camp in Antarctica
Russian researchers have found unidentified bacteria in waters of the unique sub-glacial Lake Vostok. However, this is not a sensational discovery since the microorganism was found in possible kerosene contaminated waters.

The finding from the water sample taken in May 2012 showed that the bacteria do not belong to any of the existing classes of bacteria. Before the latest discovery, science knew only one species of bacteria that can live under these conditions.

"The last analysis was completed a week ago - there will be another, but the results are unlikely to change anything. After exclusion of all known contaminants - extraneous organisms - bacterial DNA was detected, which does not coincide with any of the known species in the world," RIA Novosti quotes Sergey Bulat of the St. Petersburg Nuclear Physics Institute in Russia.

However, the discovery turns out not to be that sensational.

"There has been one strain of bacteria which we did not find in drilling liquid, but these bacteria could in principal use kerosene as an energy source," the head of the laboratory of the same institution, Vladimir Korolev said. "That is why we can't say that a previously-unknown bacteria was found," he stressed.