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October 30, 2006, 8:45 PM CT

Brain's Response To Pleasing

Brain's Response To Pleasing
We all have tastes we love, and tastes we hate. And yet, our "taste" for certain flavors and foods can change over time, as we get older or we get tired of eating the same old thing.

Now, a new University of Michigan study gives new evidence about what's going on in the brain when we taste something we like, or develop a liking for something we once hated.

And eventhough the study used rats instead of people, it has direct implications for understanding the way we perceive pleasure and the reasons why some people develop problems, such as drug abuse, depression or anorexia, that knock their pleasure response off balance.

In a new paper in the recent issue of the Journal of Neurophysiology, U-M neuroresearchers and psychology experts report the findings from direct monitoring of an area of the brain known as the ventral pallidum. Located deep in the brain, it's a kind of traffic center for signals from different areas of the brain that process tastes and pleasurable sensations.

The scientists were able to track the activity of brain cells in that area while the rats received water, salt water and sugar water directly into their mouths. They also recorded how the rats behaved while they tasted those different solutions, including signs that they liked or disliked the tastes. And, they repeated the tests when the rats had been treated with drugs that greatly reduced their bodies' salt levels.........

Posted by: Nora      Permalink         Source


October 30, 2006, 8:30 PM CT

3-D ultrasound and robotic surgery

3-D ultrasound and robotic surgery Image courtesy of Cleveland Clinic
Duke University engineers have shown that a three-dimensional ultrasound scanner they developed can successfully guide a surgical robot.

The scanner could find application in various medical settings, according to the researchers. They said the scanner ultimately might enable surgeries to be performed without surgeons, a capability that could prove valuable in space stations or other remote locations.

"It's the first time, to our knowledge, that anyone has used the information in a 3-D ultrasound scan to actually guide a robot," said Stephen Smith, professor of biomedical engineering at Duke's Pratt School of Engineering.

Smith and Eric Pua, a Pratt graduate student who participated in the research, reported the findings in the cover article of the November 2006 issue of the journal IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control http://www.ieee-uffc.org/tr/covers/2006toc.htm#nov06.

The work was supported by the National Institutes of Health and the National Science Foundation.

In their demonstration, the researchers used 3-D ultrasound images to pinpoint in real time the exact location of targets in a simulated surgical procedure. That spatial information then guided a robotically controlled surgical instrument right to its mark.........

Posted by: John      Permalink         Source


October 29, 2006, 8:11 PM CT

New insight into cell division

New insight into cell division Abnormal mitotic spindle, whose deformation is caused by defective cell division control.
Image: Max Planck Institute for Molecular Genetic
When cells divide, control mechanisms ensure that the genetic material, in other words the chromosomes, is correctly distributed to the daughter cells. Researchers at the Max Planck Institute for Molecular Genetics in Berlin have now explained the molecular principles of these control processes. The so-called checkpoint kinases, i.e. the enzymes which perform this controlling, are not directly associated only with the chromosomes, as was previously assumed to be the case. On the contrary, they interact with a different category of proteins which are involved in the development of the cell division spindle. This finding is highly significant, since incorrect distribution of the chromosomes can lead to abnormalities and diseases such as cancer. The new understanding of this process will in turn promote a better understanding of the molecular principles of the development of cancer (Science, October 27, 2006).

The rod-shaped filaments of the microtubules are responsible for dividing the chromosomes in a cell. They form a connection between the starting point in the chromosomes, the kinetochors, and the centrosome. The centrosome organizes the spindle-shaped arrangement of the microtubule filaments in the cell by means of gamma tubulin ring complexes. Until now it was assumed that control of even distribution of chromosomes was only monitored by the checkpoint kinases in the kinetochors. When microtubules are correctly attached to the kinetochors, these kinases then inform the cell that a precise distribution of chromosomes can be carried out.........

Posted by: Nora      Permalink         Source


October 29, 2006, 6:53 PM CT

Mind of the Bumblebee

Mind of the Bumblebee
Rebecca Flanagan has probably come as close as a human can to reading the mind of a bumblebee.

Flanagan, a graduate student in biological sciences, and Associate Professor Jeffrey Karron are studying the behaviors of bees as they gather pollen - which plant species the bees forage on, which flowers they probe and in what order, and how many blooms they visit before moving on to another plant. In doing so, the bees make plant reproduction possible by dispersing pollen.

To predict where each bee that she tracks will carry its pollen next, Flanagan has to literally think like one.

"Once they've learned a foraging style that's been successful, they are more likely to stick with it rather than invest time in learning something new," says Flanagan.

But why go to such lengths to map the flight of the bumblebee? It may seem random and inconsequential. But it is neither, says Karron.

The bees are pivotal players in determining which plant populations survive through successful reproduction. If scientists could better understand nature's decision-making process, then they could use the information to increase crop yields and to boost conservation of native plant communities.

Best bee practices

Because there are many bee behaviors, the task isn't simple, but with tedious scrutiny it is documentable.........

Posted by: Nora      Permalink         Source


October 27, 2006, 9:02 PM CT

Mate-attracting Chemicals in Silk worms

Mate-attracting Chemicals in Silk worms Silkworm moths are white-haired with two-inch wingspans
It's all about "the birds and the bees." And now, "the silkworm moths and the fruit flies".

A chemical ecologist and a genetics researcher at the University of California, Davis, have joined forces to trick fruit flies into thinking that silkworm moths are potential mates.

Groundbreaking research in the labs of chemical ecologist Walter Leal and genetics researcher Deborah Kimbrell shows that genetically engineered fruit flies responded to the silkworm moth scent of a female.

The practical implications of the findings could be widespread. Methods that can attract or repel insects have important applications for agricultural pests and medical entomology. The research could lead to designing better chemicals to attract insects and designing better chemicals to suppress insect communication. That is because insects communicate or smell through their antennae.

A number of insect species, including silkworm moths, release sex pheromones or chemical signals to attract a mate. "Silkworm moths utilize smell more strongly than any other senses," said Leal, professor and chair of the Department of Entomology. "Moths keep on the trail of a scent until they find a female".

"We got a very clear response," he said. "Our electrophysiological recordings and direct stimulation testing showed that the transgenic fruit flies definitely responded to the moth pheromone".........

Posted by: Nora      Permalink         Source


October 27, 2006, 5:04 AM CT

Latest views of the V838

Latest views of the V838
Hubble has returned to the intriguing V838 Monocerotis many times since its initial outburst in 2002 to follow the evolution of its light echo. Two new images provide the most astonishing views of V838 to date.

The unusual variable star V838 Monocerotis (V838 Mon) continues to puzzle astronomers. This previously inconspicuous star underwent an outburst early in 2002, during which it temporarily increased in brightness to become 600,000 times more luminous than our Sun. Light from this sudden eruption is illuminating the interstellar dust surrounding the star, producing the most spectacular "light echo" in the history of astronomy.

As light from the eruption propagates outward into the dust, it is scattered by the dust and travels to the Earth. The scattered light has travelled an extra distance in comparison to light that reaches Earth directly from the stellar outburst. Such a light echo is the optical analogue of the sound echo produced when an Alpine yodel is reflected from the surrounding mountainsides.

The NASA/ESA Hubble Space Telescope has been observing the V838 Mon light echo since 2002. Each new observation of the light echo reveals a new and unique "thin-section" through the interstellar dust around the star. This release shows new images of the light echo from the Hubble Advanced Camera for Surveys taken in November 2005 (left) and again in September 2006 (right). The numerous whorls and eddies in the interstellar dust are particularly noticeable. Possibly they have been produced by the effects of magnetic fields in the space between the stars.........

Posted by: Edwin      Permalink         Source


October 27, 2006, 4:40 AM CT

What Makes A Bee A He Or A She?

What Makes A Bee A He Or A She?
Three years ago, scientists pinpointed a gene called csd that determines gender in honey bees, and now a research team led by University of Michigan evolutionary biologist Jianzhi "George" Zhang has unraveled details of how the gene evolved. The new insights could prove useful in designing strategies for breeding honey bees, which are major pollinators of economically important crops-and notoriously tricky to breed.

The findings of Zhang and collaborators appear in a special issue of Genome Research devoted to the biology of the honey bee. The issue will be published online and in print Oct. 26, coinciding with the publication of the honey bee genome sequence in the journal Nature.

Scientists have long known that in bees-as well as wasps, ants, ticks, mites and some 20 percent of all animals-unfertilized eggs develop into males, while females typically result from fertilized eggs. But that's not the whole story, and the discovery in 2003 of csd (the complementary sex determination gene) helped fill in the blanks. The gene has many versions, or alleles. Males inherit a single copy of the gene; bees that inherit two copies, each a different version, become female. Bees that have the misfortune of inheriting two identical copies of csd develop into sterile males but are quickly eaten at the larval stage by female worker bees.........

Posted by: Nora      Permalink         Source


October 26, 2006, 5:17 AM CT

Moderate Drinking May Boost Memory

Moderate Drinking May Boost Memory
In the long run, a drink or two a day may be good for the brain.

Scientists observed that moderate amounts of alcohol - amounts equivalent to a couple of drinks a day for a human - improved the memories of laboratory rats.

Such a finding may have implications for serious neurodegenerative diseases like Alzheimer's, said Matthew During, the study's senior author and a professor of molecular virology, immunology and cancer genetics at Ohio State University.

"There is some evidence suggesting that mild to moderate alcohol consumption can protect against diseases like Alzheimer's in humans," said During. "But it's not apparent how this happens".

He and his colleague, Margaret Kalev-Zylinska, a postdoctoral researcher at the University of Auckland, in New Zealand, uncovered a neuronal mechanism that may help explain the link between alcohol and improved memory.

"We saw a noticeable change on the surface of certain neurons in rats that were given alcohol," During said. "This change may have something to do with the positive effects of alcohol on memory".

The scientists presented their findings at the annual Society for Neuroscience conference in Atlanta.

During and Kalev-Zylinska designed a special liquid diet for the rats. One formulation included a low dose of alcohol, comparable to two or three drinks a day for a human, while the other diet included a much higher dose of alcohol, comparable to six or seven drinks a day for a human. A third group of rats was given a liquid diet without alcohol. All animals were given their respective diets daily for about four weeks.........

Posted by: Edwin      Permalink         Source


October 26, 2006, 5:04 AM CT

200-million-year-old Baby Galaxies

200-million-year-old Baby Galaxies This figure shows the relation between redshift and the age of the universe
Astronomers have taken amazing pictures of two of the most distant galaxies ever seen. The ultradeep images, taken at infrared wavelengths, confirm for the first time that these celestial cherubs are real. The researchers* are now able to weigh galaxies and determine their age at earlier times than ever before, providing important clues about the evolutionary origins of galaxies like our Milky Way. The work appears in the October 1 issue of Astrophysical Journal Letters.

Carnegie Fellow Ivo Labbe, along with Rychard Bouwens and Garth Illingworth of the UCO/Lick Observatory at the University of California, Santa Cruz, and Marijn Franx of the Leiden Observatory, examined galaxies in the Hubble Ultra Deep Field (HUDF) using the sensitive Infrared Array Camera (IRAC) aboard NASA's Spitzer Space Telescope. The HUDF, scanned by NASA's Hubble Space Telescope in late 2003, remains the deepest view ever taken at visible and near-infrared wavelengths.

The two galaxies are seen when the universe was just a baby-700 million years after the Big Bang, or five percent of the universe's current age. They belong to a precious small sample of similarly ancient galaxies, discovered two years ago by Bouwens, Illingworth, and Franx and analyzed in-depth in Nature last month. The relative deficit of such far-away luminous sources indicates that this early period is when galaxies were rapidly building up from a very small number of stars to the massive galaxies we see at later times.........

Posted by: Edwin      Permalink         Source


October 26, 2006, 4:57 AM CT

Pollinators Help One-third Of Crop Production

Pollinators Help One-third Of Crop Production Raspberries, Rubus ideaus L, after passive self-pollination (left and middle) and open insect pollination (right). (Photo by Jim Cane, Bee Research Institute, Longan, USA)
Pollinators such as bees, birds and bats affect 35 percent of the world's crop production, increasing the output of 87 of the leading food crops worldwide, finds a new study published recently (Wednesday, Oct. 25), in the Proceedings of the Royal Society B: Biological Sciences and co-authored by a conservation biologist at the University of California, Berkeley.

The study is the first global estimate of crop production that is reliant upon animal pollination. It comes one week after a National Research Council (NRC) report detailed the troubling decline in populations of key North American pollinators, which help spread the pollen needed for fertilization of such crops as fruits, vegetables, nuts,.

Of particular concern in the NRC report was the decline of the honey bee, a species introduced from Europe and a critical pollinator for California's almond industry. The report pointed out that it takes about 1.4 million colonies of honey bees to pollinate 550,000 acres of this state's almond trees.

In an effort to better understand how dependent crop production is upon pollinators worldwide, an international research team led by Alexandra-Maria Klein, an agroecologist from the University of Goettingen in Gera number of, conducted an extensive review of scientific studies from 200 countries and for 115 of the leading global crops.........

Posted by: Nora      Permalink         Source


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