Science & TechnologyS


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New 'Stars' in Formation of Nerve Cell Insulation


ScienceDaily
Tue, 21 Mar 2006 00:00 UTC
The insulating myelin sheath enwrapping the cable-like axons of nerve cells is the major target of attack of the immune system in multiple sclerosis. Such attack causes neural short-circuits that give rise to the muscle weakness, loss of coordination, and speech and visual loss in the disease.

Now, Douglas Fields of the National Institute of Child Health and Human Development and his colleagues have reported in Neuron that supporting cells called astrocytes in the central nervous system (CNS) promote myelination by releasing an immune system molecule that triggers myelin-forming cells to action. The finding, they say, "may offer new approaches to treating demyelinating diseases."

Astrocytes, so named because of their star-like shape, are the most prominent supporting cells in the nervous system. They provide critical regulatory molecules that enable nerve cells to develop and connect properly.
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Studying Glial Cells in the Roundworm May Provide Insight into Human Brain Diseases


ScienceDaily
Tue, 07 Jun 2005 00:00 UTC
The key to understanding our brains may lie within a one-millimeter long worm, new research from Rockefeller University indicates. Reporting in the June issue of Developmental Cell, Shai Shaham, Ph.D., and graduate student Elliot Perens use the roundworm, C. elegans, to investigate the mysterious glial cell, which makes up 90 percent of the human brain and, when it malfunctions, can contribute to diseases like Parkinson's disease and schizophrenia.

Studying glial cells is technically difficult as they are essential for neuronal cell survival: disturbing them in any way puts the organism's life in jeopardy. Shaham and Perens show that worms are the perfect model system to study the function of these cells in the nervous system, because the glial cells can be manipulated and the neurons still form and function, though not entirely as normal.

"Glial cells have been traditionally hard to study in vertebrates because it is difficult to ask how they influence neurons beyond how they affect a neuron's survival," says Shaham, head of the Strang Laboratory of Developmental Genetics. "This is the first paper to take a serious crack at glial cells in C. elegans. It shows that the worm really is a great system in which to study glial cells, because we are able to get the kind of answers that could help us understand how they are functioning in the human brain."
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Brain Synapse Formation Linked to Proteins, Stanford Study Finds


ScienceDaily
Sun, 20 Feb 2005 00:00 UTC
Critical connections that neurons form in the brain during development turn out to rely on common but overlooked cells, called glia. These cells were known to support the neurons in adults, but had never been fingered as players in forming the connections between neurons, known as synapses.

The Stanford University School of Medicine researchers who conducted the work, led by Ben Barres, MD, PhD, professor of neurobiology, also discovered two of the proteins made by glial cells that signal synapse formation. This study, published in the Feb. 11 issue of Cell, could help researchers understand diseases such as epilepsy and addiction in which too many synapses form.

"We knew glia had a close relationship with neurons," Barres said. "We never thought the synapses would entirely fail to form without the glia." In fact, that relationship was considered so unlikely that the grant application was turned down six times because the work was considered too risky.
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Zebrafish May Hold Key to Understanding Human Nerve Cell Development


ScienceDaily
Fri, 07 Jan 2005 00:00 UTC
Traditionally viewed as supporting actors, cells known as glia may be essential for the normal development of nerve cells responsible for hearing and balance, according to new University of Utah research. The study is reported in the January 6, 2005 issue of Neuron and is co-authored by scientists at the University of Washington.

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© Tatjana Piotrowski/University of Utah School of MedicineZebrafish Neuromasts: A) The posterior lateral line placode in a 35 h old live larva stained with Bodipy. The placode drops off neuromast precursors as it migrates posteriorly on the trunk. B) Differentiated neuromast with hair bundles in a 4 d old larva. C) 5 d old live larva in which the neuromasts are stained with the fluorescent dye Daspei.
"Using zebrafish as a model, we've demonstrated that glial cells play a previously unidentified role in regulating the development of sensory hair cell precursors -- the specialized neurons found in the inner ear of humans that make hearing possible. This research increases our understanding of how nerve cells develop and whether it may be possible to regenerate these types of cells in humans one day," said Tatjana Piotrowski, Ph.D., assistant professor of neurobiology and anatomy at the University of Utah School of Medicine.

Scientists long have known that glial cells, or simply glia, are essential for healthy nerve cells. However, in the last 10 years scientists have learned that glia aren't just "glue" holding nerve cells together. Glia communicate with each other and even influence synapse formation between neurons.
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Using Modern Sequencing Techniques to Study Ancient Modern Humans

Cathleen Genova
Cell Press
Thu, 31 Dec 2009 06:00 UTC
DNA that is left in the remains of long-dead plants, animals, or humans allows a direct look into the history of evolution. So far, studies of this kind on ancestral members of our own species have been hampered by scientists' inability to distinguish the ancient DNA from modern-day human DNA contamination.

Now, research by Svante Pääbo from The Max-Planck Institute for Evolutionary Anthropology in Leipzig, published online on December 31st in Current Biology - a Cell Press publication - overcomes this hurdle and shows how it is possible to directly analyze DNA from a member of our own species who lived around 30,000 years ago.

DNA - the hereditary material contained in the nuclei and mitochondria of all body cells - is a hardy molecule and can persist, conditions permitting, for several tens of thousands of years. Such ancient DNA provides scientists with unique possibilities to directly glimpse into the genetic make-up of organisms that have long since vanished from the Earth. Using ancient DNA extracted from bones, the biology of extinct animals, such as mammoths, as well as of ancient humans, such as the Neanderthals, has been successfully studied in recent years.

The ancient DNA approach could not be easily applied to ancient members of our own species. This is because the ancient DNA fragments are multiplied with special molecular probes that target certain DNA sequences.
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Laptop

McAfee's prediction for 2010: Adobe will replace Microsoft as hacker's target

Nick Farrell
Fudzilla
Wed, 30 Dec 2009 09:04 UTC
Tarot readers working for the insecurity outfit McAfee are predicting that hackers will give up trying to turn over Microsoft and focus on Adobe stuff instead.

In 2009, as attacks on client software increased, cybercriminals' favourite products were Adobe Flash and Acrobat Reader. McAfee expects that next year things will get worse with attackers exploiting vulnerabilities in Flash applications via the Web and Acrobat documents via e-mail attachments.

"We expect that in 2010 Adobe product exploitation is likely to surpass that of Microsoft Office applications in the number of desktop PCs being attacked," the report said.
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Saturn

Reflection of Sunlight off Titan Lake

NASA/JPL/University of Arizona/DLR
Nasa.gov
Thu, 31 Dec 2009 07:49 UTC
Titan
© NASA/JPL/University of Arizona/DLR A flash of sunlight reflected off a lake on Saturn’s moon Titan
This image shows the first flash of sunlight reflected off a lake on Saturn's moon Titan. The glint off a mirror-like surface is known as a specular reflection. This kind of glint was detected by the visual and infrared mapping spectrometer (VIMS) on NASA's Cassini spacecraft on July 8, 2009. It confirmed the presence of liquid in the moon's northern hemisphere, where lakes are more numerous and larger than those in the southern hemisphere. Scientists using VIMS had confirmed the presence of liquid in Ontario Lacus, the largest lake in the southern hemisphere, in 2008.
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Sun

Sunspot Surge


Space Weather
Wed, 30 Dec 2009 21:27 UTC
2009 is ending with a flurry of sunspots. Indeed, if sunspot 1039 holds together just one more day (prediction: it will), the month of December will accumulate a total of 22 spotted days and the final tally for the year will look like this:

Image
© NOAA
The dark line is a linear least-squares fit to the data. If the trend continues exactly as shown (prediction: it won't), sunspots will become a non-stop daily occurance no later than February 2011. Blank suns would cease and solar minimum would be over.
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Telescope

Blue Moon Eclipse


Space Weather
Wed, 30 Dec 2009 21:22 UTC
On Dec. 31st, the Blue Moon will dip into Earth's shadow for a partial lunar eclipse. The event is visible from Europe, Africa and Asia: map. At maximum eclipse, around 19:24 Universal Time, approximately 8% of the Moon will be darkly shadowed. Click here to launch an animated preview.

Image
© Larry Koehn
Blue Moons are rare (once every ~2.5 years). Blue Moons on New Year's Eve are rarer still (once every ~19 years). How rare is a lunar eclipse of a Blue Moon on New Year's Eve?
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Telescope

Blue Moon On New Year's Eve

Dr. Tony Phillips
Science @ NASA
Wed, 30 Dec 2009 21:14 UTC
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© Stefano De Rosa The full moon of Dec. 2, 2009, over Turan, Italy. Photographer Stefano De Rosa notes that the blue colors are cast by Christmas lights surrounding the pictured church.
Party planners take note. For the first time in almost twenty years, there's going to be a Blue Moon on New Year's Eve. "I remember the last time this happened," says professor Philip Hiscock of the Dept. of Folklore at the Memorial University of Newfoundland. "December 1990 ended with a Blue Moon, and many New Year's Eve parties were themed by the event. It was a lot of fun."

Don't expect the Moon to actually turn blue, though. "The 'Blue Moon' is a creature of folklore," he explains. "It's the second full Moon in a calendar month."

Most months have only one full Moon. The 29.5-day cadence of the lunar cycle matches up almost perfectly with the 28- to 31-day length of calendar months. Indeed, the word "month" comes from "Moon." Occasionally, however, the one-to-one correspondence breaks down when two full Moons squeeze into a single month. Dec. 2009 is such a month. The first full Moon appeared on Dec. 2nd; the second, a "Blue Moon," will come on Dec. 31st.

This definition of Blue Moon is relatively new. If you told a person in Shakespeare's day that something happens "once in a Blue Moon" they would attach no astronomical meaning to the statement. Blue moon simply meant rare or absurd, like making a date for the Twelfth of Never. "But meaning is a slippery substance," says Hiscock. "The phrase 'Blue Moon' has been around for more than 400 years, and during that time its meaning has shifted."
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