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Scientists Explain Puzzling Lake Asymmetry on Titan


ScienceDaily
Sun, 29 Nov 2009 05:00 UTC
Image
© NASA
The disparity between the abundance of lakes in the north and their paucity in the South
Researchers at the California Institute of Technology (Caltech) suggest that the eccentricity of Saturn's orbit around the sun may be responsible for the unusually uneven distribution of methane and ethane lakes over the northern and southern polar regions of the planet's largest moon, Titan. On Earth, similar "astronomical forcing" of climate drives ice-age cycles.

A paper describing the theory appears in the November 29th advance online edition of Nature Geoscience.

As revealed by Synthetic Aperture Radar (SAR) imaging data taken by NASA's Cassini spacecraft, which has been surveying Saturn and its moons since 2004, liquid hydrocarbon-filled lakes in Titan's northern high latitudes cover 20 times more area than lakes in the southern high latitudes. There are also significantly more partially filled and now-empty lakes in the north. (In the SAR data, smooth features -- like the surfaces of lakes -- appear as dark areas, while rougher features -- such as the bottom of an empty lake -- appear bright.)
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Forming New Brain Cells: Key Regulatory Peptide Discovered


ScienceDaily
Sun, 29 Nov 2009 00:00 UTC
The generation of new nerve cells in the brain is regulated by a peptide known as C3a, which directly affects the stem cells' maturation into nerve cells and is also important for the migration of new nerve cells through the brain tissue, reveals new research from the Sahlgrenska Academy published in the journal Stem Cells.

Although the research has been carried out using mice and cultured cells, it could lead to a new medicine for human beings, which could be given to patients who have had a stroke or other disorders that damage or destroy the nerve cells. "Our research findings show that it could be possible to use molecules that are similar to the peptide C3a to boost the formation of nerve cells and stimulate the replacement of nerve cells lost due to injury or illness," says senior lecturer Marcela Pekna who headed the research group at the Sahlgrenska Academy.

The peptide C3a is generated through the activation of the complement system, a group of proteins in the blood that is essential for the body's immune defence. "Our research group was the first in the world to show that the complement system also plays an important role in the repair and regeneration of the brain," says Pekna. "This was a surprising discovery that opened up a whole new field of research."
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'Glow-in-the-Dark' Red Blood Cells Made from Human Stem Cells


ScienceDaily
Sun, 29 Nov 2009 00:00 UTC
Image
© Monash University
Human embryonic stem cells modified to glow red when the stem cells become red blood cells.
Victorian stem cell scientists from Monash University have modified a human embryonic stem cell (hESC) line to glow red when the stem cells become red blood cells.

The modified hESC line, ErythRED, represents a major step forward to the eventual aim of generating mature, fully functional red blood cells from human embryonic stem cells.

The research, conducted by a team led by Professors Andrew Elefanty and Ed Stanley at the Monash Immunology and Stem Cell Laboratories that included scientists at the Murdoch Children's Research Institute, was published in the August 25 issue of the journal, Nature Methods.

The work, funded by the Australian Stem Cell Centre (ASCC), will help scientists to track the differentiation of embryonic stem cells into red blood cells.

Whilst hESCs have the potential to turn into any cell type in the body, it remains a scientific challenge to reliably turn these stem cells into specific cell types such as red blood cells. The development of the ErythRED embryonic stem cell line, which fluoresces red when haemoglobin genes are switched on, is an important development that will help researchers to optimise the conditions that generate these cells.
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Mass Extinction: Why Did Half of North America's Large Mammals Disappear 40,000 to 10,000 Years Ago?


ScienceDaily
Fri, 27 Nov 2009 03:00 UTC
Image
© iStockphoto
Artist's rendering of a woolly mammoth family.
Years of scientific debate over the extinction of ancient species in North America have yielded many theories. However, new findings from J. Tyler Faith, GW Ph.D. candidate in the hominid paleobiology doctoral program, and Todd Surovell, associate professor of anthropology at the University of Wyoming, reveal that a mass extinction occurred in a geological instant.

During the late Pleistocene, 40,000 to 10,000 years ago, North America lost over 50 percent of its large mammal species. These species include mammoths, mastodons, giant ground sloths, among many others. In total, 35 different genera (groups of species) disappeared, all of different habitat preferences and feeding habits.

What event or factor could cause such a mass extinction? The many hypotheses that have been developed over the years include: abrupt change in climate, the result of comet impact, human overkill and disease. Some researchers believe that it may be a combination of these factors, one of them, or none.
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Scientists Identify Two Molecules that Affect Brain Plasticity in Mice


ScienceDaily
Sat, 28 Nov 2009 05:00 UTC
You wouldn't want a car with no brakes. It turns out that the developing brain needs them, too.

Researchers at the Stanford University School of Medicine have identified a set of molecular brakes that stabilize the developing brain's circuitry. Moreover, experimentally removing those brakes in mice enhanced the animals' performance in a test of visual learning, suggesting a long-term path to therapeutic application.

In a study to be published Nov. 25 in Neuron, Carla Shatz, PhD, professor of neurobiology and of biology, and her colleagues have implicated two members of a large family of proteins critical to immune function (collectively known as HLA molecules in humans and MHC1 molecules in mice) in brain development. Until recently, these immune-associated molecules were thought to play no role at all in the healthy brain.

In previous studies, Shatz and her co-investigators have shown that MHC molecules are found on the surfaces of nerve cells in the brain, and that they temper "synaptic plasticity": the ease with which synapses -- the more than 100 trillion points of contact between nerve cells that determine brain circuitry -- are strengthened, weakened, created or destroyed in response to experience. In one recent study, the Shatz group tied two specific members of the MHC1 family, called K and D, to the ability of circuits in a brain region responsible for motor learning to be refined by a learning experience.
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RNA Network Seen in Live Bacterial Cells for First Time


ScienceDaily
Sat, 28 Nov 2009 03:00 UTC
Image
© Natalia E. Broude
These are fluorescent images of E. coli bacterial cells with visualized RNA.
Scientists who study RNA have faced a formidable roadblock: trying to examine RNA's movements in a living cell when they can't see the RNA. Now, a new technology has given scientists the first look ever at RNA in a live bacteria cell -- a sight that could offer new information about how the molecule moves and works.

Interest in RNA, which plays a key role in manufacturing proteins, has increased in recent years, due in large part to its potential in new drug therapies. RNA localization and movement in bacterial cell are poorly understood. The problem has been finding a way to mark RNA in a living cell so that scientists can track it, says Natasha Broude, a research associate professor at Boston University's Department of Biomedical Engineering.

"You can label any protein within the cell and watch what it is doing," says Broude, a senior researcher on the new study, published in a recent issue of the Proceedings of the National Academy of Sciences. "For RNA it was much more difficult because RNA is more mobile and less stable than both proteins and DNA."

Before now, scientists used green fluorescent protein (GFP) to label RNA in a cell. But proteins were also tagged with GFP and their fluorescence was so bright, it drowned out the glow from the RNA. "The initial idea was to do something to allow us to decrease background fluorescence," Broude says.
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Satellite

Signal Fading on Radio Traffic Reports

Daisy Nguyen
The Associated Press
Fri, 27 Nov 2009 23:00 UTC
For more than 20 years, Mike Nolan was known to radio listeners as the "eye in the sky." He flew over Southern California freeways in his single-engine plane, reporting on the nation's worst traffic.

These days, he broadcasts about traffic snarls and lurking gridlock without leaving the ground - without even leaving his home in this Los Angeles suburb. Sitting in a chair behind computer monitors and a television, Nolan gathers traffic data and broadcasts live on two radio stations a day.

"What I'm best suited to do is look out the airplane window and tell people what I see," Nolan, 60, said. "When I was grounded, that world changed considerably so I had to reinvent myself."

His return to earth reflects the evolution of the traffic reporting business as a faltering economy forces news operation cutbacks, technology displaces traditional reporters and motorists increasingly rely on cell phones and GPS to monitor live traffic.
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Info

Experts scan disease links with Chinese "gene map"

Tan Ee Lyn
Reuters.com
Fri, 27 Nov 2009 18:46 UTC
Image
© REUTERS/China Daily
People hold a Chinese national flag ahead of a raising-flag ceremony during a photo call at Yangren Street in Chongqing Municipality, September 29, 2009.
Hong Kong - A large analysis of the genes of 8,200 ethnic Chinese has revealed subtle genetic differences between inhabitants in northern China and southern China, and even between different Chinese dialect groups.

Published in the American Journal of Human Genetics, the study is important as scientists are trying to identify if certain gene variants may render some people more vulnerable to some diseases -- so that targeted preventive measures can be taken and therapies may one day be found.
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Mural reveals ancient connection to Uzbekistan

Yim Seung-hye
JoongAng Daily
Fri, 27 Nov 2009 18:37 UTC
Image
© Provided by the National Museum of Korea
A replica of an ancient mural that is part of an exhibition at the National Museum of Korea shows the connections between Korea and Uzbekistan.
In most cases, replicas of ancient treasures or great works of art are treated with contempt. But with relics that are at risk of aging or disintegration, replicas can play an integral role in our understanding of the original works and the time in which they were made.

In 1965, a mural was discovered in Samarkand, Uzbekistan, when local authorities decided to build a road in the middle of the Afrasiab tepe. A tepe is a mound marking an ancient site, in this case pre-Mongol Samarkand.

When it was found, the mural was weathered and its images obscured. But those who discovered it had the foresight to make a drawing of it, from which replicas have been made.
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10,000-year-old weapon found at site of new Ontario arena

Gary Rennie
Windsor Star
Fri, 27 Nov 2009 18:20 UTC
Image
© Unknown
Early Paleoindian fluted (or grooved) spear points that date to ca. 12,500 to 13,000 years old in our calendar
Archaeologists in Windsor, Ont., have discovered a 10,000-year-old stone weapon created by the first humans who lived in the province.

Newmarket archaeologist Kim Slocki said she found a single "projectile point" in her pre-construction survey of the site of a new arena.

"It's at least 10,000 years old," Slocki said.

She said the artifact comes from Paleoindian hunters often called the "first people of Ontario."
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