Science & TechnologyS


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How the Brain Encodes Memories at a Cellular Level


ScienceDaily
Fri, 25 Dec 2009 00:00 UTC
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© Sourav BanerjeeThis is a neuron.
Scientists at UC Santa Barbara have made a major discovery in how the brain encodes memories. The finding, published in the December 24 issue of the journal Neuron, could eventually lead to the development of new drugs to aid memory.

The team of scientists is the first to uncover a central process in encoding memories that occurs at the level of the synapse, where neurons connect with each other.

"When we learn new things, when we store memories, there are a number of things that have to happen," said senior author Kenneth S. Kosik, co-director and Harriman Chair in Neuroscience Research, at UCSB's Neuroscience Research Institute. Kosik is a leading researcher in the area of Alzheimer's disease.

"One of the most important processes is that the synapses -- which cement those memories into place -- have to be strengthened," said Kosik. "In strengthening a synapse you build a connection, and certain synapses are encoding a memory. Those synapses have to be strengthened so that memory is in place and stays there. Strengthening synapses is a very important part of learning. What we have found appears to be one part of how that happens."
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Earth on Track for Epic Die-Off, Scientists Say

Peter Fimrite
Sam Francisco Chronicle
Sat, 19 Dec 2009 06:00 UTC
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© Mauricio Anton/UCLAA reconstructed scene in the Pleistocene of western North America, showing a group of three sabertooth cats (Smilodon fatalis).
If the course of human history is any model, then the wheels are already turning on Earth's sixth mass extinction, thanks to habitat destruction, pollution and now global warming, a scientific analysis of millions of years of data revealed Friday.

The study of the fossil and archaeological record over the past 30 million years by UC Berkeley and Penn State University researchers shows that between 15 and 42 percent of the mammals in North America disappeared after humans arrived.

That means North American mammals are well on the way - perhaps as much as half way - to a level of extinction comparable to other epic die-offs, like the one that wiped out the dinosaurs.

Anthony Barnosky, a UC Berkeley professor of integrative biology and co-author of the study, said the most dramatic human-caused impacts on the ecosystem have occurred in the last century.
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Chemical Energy Influences Tiny Vibrations of Red Blood Cell Membranes


ScienceDaily
Thu, 24 Dec 2009 06:00 UTC
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© Alex Jerez, YongKeun Park, Gabriel Popescu, and Subra SureshPictured is an artist's rendering of human red blood cell.
Much like a tightly wound drum, red blood cells are in perpetual vibration. Those vibrations help the cells maintain their characteristic flattened oval or disc shape, which is critical to their ability to deform as they traverse blood vessels in the body to deliver oxygen to tissues.

Blood disorders such as malaria, sickle cell anemia and spherocytosis interfere with those vibrations, so a better understanding of the vibrations could help researchers develop treatments for those diseases. However, the vibrations are nearly impossible to study because their amplitude is so tiny (nanometer, or billionth of a meter, scale), and they occur in just milliseconds.

A year ago, a team led by MIT Dean of Engineering Subra Suresh and Physics Professor Michael Feld, director of MIT's George R. Harrison Spectroscopy Laboratory, reported the first whole-cell glimpse of these membrane fluctuations. Now, in a paper appearing in the Proceedings of the National Academy of Sciences, they present conclusive evidence that the vibrations require energy input from ATP (adenosine triphosphate), a chemical cells use to store and transfer energy.
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Fight Infection by Disturbing How Bacteria Communicate


ScienceDaily
Thu, 24 Dec 2009 00:00 UTC
Researchers from the University of Groningen have clarified the structure of an enzyme that disturbs the communication processes between bacteria. By doing so they have laid the foundations for a new method of tackling bacterial infections such as cystic fibrosis. An article on the structure and function of the so-called quorum-quenching acylase was published on 21 December 2009 in the online edition of the Proceedings of the National Academy of Sciences (PNAS).

Although bacteria are simple single-celled organisms, they are capable of communicating with each other. Bacteria talk to each other by exchanging tiny hormone-like signal molecules. By means of this process of 'quorum sensing', the activities of a large group of bacteria are synchronized. Thus bacteria can adapt quickly to changes in their environment such as the running out of nutrients or the arrival of rival microorganisms.

The production of factors that determine the virulence of a bacterium is also controlled by these signal molecules. This enables bacteria to remain invisible to the immune system in the early stages of infection. As soon as the group of informed bacteria -- the quorum -- is sufficiently large, the attack on the infected host is initiated by starting up the production of toxins and other virulence factors.
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Telescope

Herschel Space Telescope Uncovers Sources of Cosmic Infrared Background


ScienceDaily
Thu, 24 Dec 2009 06:00 UTC
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© Max Planck Institute for Extraterrestrial PhysicsHerschel-PACS images of the ‘GOODS-N’ field in the constellation of Ursa Major at far-infrared wavelengths of 100 and 160micrometres.
A weak cosmic infrared radiation field that reaches Earth from all directions contains not yet deciphered messages about the evolution of galaxies. Using first observations with the PACS Instrument on board ESA's Herschel Space Telescope, scientists from the Max Planck Institute for Extraterrestrial Physics and other institutions have for the first time resolved more than half of this radiation into its constituting sources. Observations with Herschel open the road towards understanding the properties of these galaxies, and trace the dusty side of galaxy evolution.

In the mid 1990's, scientists analyzing data from NASA's COBE spacecraft discovered faint radiation in the far-infrared part of the electromagnetic spectrum that reaches earth with the same intensity from all directions in space. Immediately, they suspected it to be the aggregate emission of many distant galaxies in the early universe, releasing the same amount of energy in the far-infrared as reaches us in visible light from similarly distant galaxies.

Whereas visible light tells us about the stars in galaxies, the far-infrared is emitted by cold dust that is hiding the newly formed stars. Identifying these surprisingly numerous dusty galaxies has proven difficult, though. Space telescopes are needed to detect far-infrared emission, because it is absorbed by the Earth's atmosphere. Previous infrared space telescopes have detected far-infrared light from only the brightest of the galaxies forming this cosmic background. To glean any information about the fainter objects, astronomers had to rely on indirect evidence based on shorter wavelength radiation.
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Satellite

Fluffy Mystery at Edge of Solar System Solved


SPACE.com
Wed, 23 Dec 2009 15:54 UTC
edge
© NASA/JPLArtist's rendering depicts the Voyager 2 spacecraft as it studies the outer limits of the heliosphere - a magnetic 'bubble' around the Solar System that is created by the solar wind. Scientists observed the magnetic bubble is not spherical, but pressed inward in the southern hemisphere.
Our solar system is passing through a cloud of interstellar material that shouldn't be there, astronomers say. And now the decades-old Voyager spacecraft have helped solved the mystery.

The cloud is called the "Local Fluff." It's about 30 light-years wide and holds a wispy mix of hydrogen and helium atoms, according to a NASA statement released today. Stars that exploded nearby, about 10 million years ago, should have crushed the Fluff or blown it away.

So what's holding the Fluff in place?

"Using data from Voyager, we have discovered a strong magnetic field just outside the solar system," explained Merav Opher, a NASA Heliophysics Guest Investigator from George Mason University. "This magnetic field holds the interstellar cloud together ["The Fluff"] and solves the long-standing puzzle of how it can exist at all."

The Fluff is much more strongly magnetized than anyone had previously suspected," Opher said. "This magnetic field can provide the extra pressure required to resist destruction."
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Mystery Solved? Scientists Now Know How Smallpox Kills


ScienceDaily
Wed, 23 Dec 2009 00:00 UTC
A team of researchers working in a high containment laboratory at the Centers for Disease Control and Prevention in Atlanta, GA, have solved a fundamental mystery about smallpox that has puzzled scientists long after the natural disease was eradicated by vaccination.: they know how it kills us. In a new research report appearing online in The FASEB Journal, researchers describe how the virus cripples immune systems by attacking molecules made by our bodies to block viral replication.

This discovery fills a major gap in the scientific understanding of pox diseases and lays the foundation for the development of antiviral treatments, should smallpox or related viruses re-emerge through accident, viral evolution, or terrorist action.

"These studies demonstrate the production of an interferon binding protein by variola virus and monkeypox virus, and point at this viral anti-interferon protein as a target to develop new therapeutics and protect people from smallpox and related viruses," said Antonio Alcami, Ph.D., a collaborator on the study from Madrid, Spain. "A better understanding of how variola virus, one of the most virulent viruses known to humans, evades host defenses will help us to understand the molecular mechanisms that cause disease in other viral infections."
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Sun

See sunspots run


Watts Up With That?
Mon, 21 Dec 2009 16:54 UTC
The sun is showing signs of life. There are no fewer than five active regions on the sun's surface, shown here in an extreme ultraviolet photo taken this morning by the Solar and Heliospheric Observatory (SOHO):

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© SOHO/Spaceweather.com
Each circle contains a sunspot or proto-sunspot belonging to new Solar Cycle 24. After two years of record-low sunspot numbers and many month-long stretches of utter quiet, this is a notable outbreak. Whether it heralds a genuine trend or merely marks a temporary, statistical uptick in activity remains to be seen.
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Info

An inexpensive 'dipstick' test for pesticides in foods

Michael Bernstein
American Chemical Society
Tue, 22 Dec 2009 19:56 UTC
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© The American Chemical SocietyA test strip shows a visible color change indicating the presence of pesticides, and advance toward a dipstick test for foods and beverages.
Scientists in Canada are reporting the development of a fast, inexpensive "dipstick" test to identify small amounts of pesticides that may exist in foods and beverages. Their paper-strip test is more practical than conventional pesticide tests, producing results in minutes rather than hours by means of an easy-to-read color-change, they say.
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Telescope

Brown Dwarf Pair Mystifies Astronomers

Andrea Messer
Penn State Live
Mon, 21 Dec 2009 17:28 UTC
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© NASAArtist's rendition of a brown dwarf and its moon orbiting a triple star system
Two brown dwarf-sized objects orbiting a giant old star show that planets may assemble around stars more quickly and efficiently than anyone thought possible, according to an international team of astronomers.

"We have found two brown dwarf-sized masses around an ordinary star, which is very rare," said Alex Wolszczan, Evan Pugh professor of astronomy and astrophysics, Penn State and lead scientist on the project.

The star, BD +20 2457, is a K2 giant -- an old bloated star nearing the end of its life. Seeing a pair of brown dwarfs around a K-type giant is a first for astronomers and offers a unique window into how they can be produced. The researchers from the Torun Center for Astronomy, Poland and the Center for Exoplanets and Habitable Worlds, Penn State report their findings in the current issue of the Astrophysical Journal.
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