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Offline neilep

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XXL from Too Few Zs? Skimping on sleep might cause obesity, diabetes
Ben Harder

Widespread sleep deprivation could partly explain the current epidemics of both obesity and diabetes, emerging data suggest.

Too little sleep may contribute to long-term health problems by changing the concentrations of hormones that control appetite, increasing food intake, and disrupting the biological clock, according to Eve Van Cauter of the University of Chicago.

Van Cauter and other researchers discussed possible links between sleep deprivation, expanding waistlines, and obesity-related problems this week in Washington, D.C., at a meeting titled A Scientific Workshop on Sleep Loss and Obesity: Interacting Epidemics.

Researchers have observed that people who sleep less than 7 to 8 hours a night have elevated rates of obesity and diabetes. In late 2004, Karine Spiegel of the Free University of Brussels in Belgium and Van Cauter conducted experiments in healthy men showing that forced sleep restriction for 2 days increased appetite and triggered changes in the appetite-related hormones ghrelin and leptin.The observed ghrelin elevation and leptin suppression may have encouraged food intake, Spiegel says.

Before that pivotal study, tests had demonstrated that obesity could disrupt sleep, but few experiments had investigated whether lack of sleep could contribute to obesity.

Preliminary results close in on an independent relationship between sleep loss and diabetes. Spiegel, Van Cauter, and their colleagues collected data from 13 volunteers who habitually sleep about 5 hours per night and from 14 others who sleep about 8 hours per night. The groups had similar body weights and ages.

Spiegel reported at the conference that the people who sleep less produce markedly elevated quantities of the hormone insulin. Their high insulin production reflects a state, called insulin resistance, that can be a harbinger of diabetes, Spiegel says.

In another new study reported at the conference, Emmanuel Mignot of Stanford University Medical School and his colleagues tested about 2,000 employees of Wisconsin government agencies. Obesity was common in that population, and volunteers who slept either significantly less or more than the overall average tended to be heavier than people getting a moderate amount of sleep, Mignot reports. Compared with people who slept 8 hours a night, those who slept 5 hours had 16 percent lower leptin concentrations and 15 percent higher ghrelin concentrations in their blood.

Mignot and his colleagues have launched a yearlong trial that will test whether prescribing extra sleep can make some obese people lose weight. He hypothesizes that an extra 1.5 hours of sleep per night might produce weight losses of 3 to 4 percent.

But Van Cauter says that when her team previously asked patients to increase nightly sleep for extended periods of time, the changes in behavior lasted only a few days.

Short sleep might encourage overeating independent of its hormonal effects, says Mignot. "When people sleep less, they have more time for eating," he notes.


SOURCE: SCIENCENEWS.ORG

Oh Joy !!..lucky me !!...though the conclusion that if you're awake more means you'll eat more is obvious isn't it ?

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Offline neilep

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Google to advertise on the moon
VNUnet Saturday April 1, 09:00 AM

 
By Arif Pollo

In the most wide-scale advertising attempt ever known,Google plans to brand itslogo into the surface of the moon so that it is visible from Earth.

The search giant will pay the US government an estimated $1bn for the rightsto the lunar land.

"You've heard of GoogleMars and GoogleEarth, where we show you maps of those planets? Well this is Google Moon,where we become the world's biggest brand," said an unnamed source at thecompany.

The Americans were the first to lay claim to the moon back in July 1969 whenNeilArmstrong took "one small step for a man, one giant leap for mankind".

Planting the flag on the Moon's surface has always been considered a gestureof being there first, but that claim has now paid off in real money terms forthe US government.

Google announced this week that it would sell afurther 5.3 billion shares to raise $2.1bn.

Google's official filing to theSecurities and ExchangeCommission said that the sale of shares was designed to raise additionalcapital for future acquisitions, but the company declined to be morespecific about any current agreements or commitments.

Analysts speculated at the time that the company must have a major purchasein mind and it is now clear where the funds will be heading.

SOURCE: YAHOO.

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Offline ariel

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Study claims ice, not water, kept Jesus afloat


University professor attempts to explain miracles with science


Tuesday, April 4, 2006; Posted: 6:54 p.m. EDT (22:54 GMT)

MIAMI, Florida (Reuters) -- The New Testament says that Jesus walked on water, but a Florida university professor believes there could be a less miraculous explanation -- he walked on a floating piece of ice.

Professor Doron Nof also theorized in the early 1990s that Moses's parting of the Red Sea had solid science behind it.

Nof, a professor of oceanography at Florida State University, said on Tuesday that his study found an unusual combination of water and atmospheric conditions in what is now northern Israel could have led to ice formation on the Sea of Galilee.

Nof used records of the Mediterranean Sea's surface temperatures and statistical models to examine the dynamics of the Sea of Galilee, which Israelis know now as Lake Kinneret.

The study found that a period of cooler temperatures in the area between 1,500 and 2,600 years ago could have included the decades in which Jesus lived.

A drop in temperature below freezing could have caused ice -- thick enough to support a human -- to form on the surface of the freshwater lake near the western shore, Nof said. It might have been nearly impossible for distant observers to see a piece of floating ice surrounded by water.

Nof said he offered his study -- published in the April edition of the Journal of Paleolimnology -- as a "possible explanation" for Jesus' walk on water.

"If you ask me if I believe someone walked on water, no, I don't," Nof said. "Maybe somebody walked on the ice, I don't know. I believe that something natural was there that explains it."

"We leave to others the question of whether or not our research explains the biblical account."

When he offered his theory 14 years ago that wind and sea conditions could explain the parting of the Red Sea, Nof said he received some hate mail, even though he noted that the idea could support the biblical description of the event.

And as his theory of Jesus' walk on ice began to circulate, he had more hate mail in his e-mail inbox.

"They asked me if I'm going to try next to explain the resurrection," he said.



http://www.cnn.com/2006/TECH/science/04/04/jesus.science.reut/index.html

ariel
« Last Edit: 05/04/2006 01:31:27 by ariel »
 

Offline DoctorBeaver

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Oh bugger, he's sussed me [:(!]

Brand new forum at
http://beaverlandforum.d4a.com
More than just science
 

Offline JimBob

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I bow in awe and reverence.

Jim

The mind is like a parachute. It works best when open.  -- A. Einstein
 

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" Testicle cells may aid research  
 
Stem cells hold the promise of many new treatments
Scientists believe the human testicle may provide a less controversial source of cells for stem cell research.
Stem cells hold great promise for new treatments for many conditions as they have the ability to become many different types of adult tissue.

But at present the most flexible type is found in human embryos - and their use is mired in controversy.

A German team describes in the journal Nature how it isolated cells from mice testes that seem equally useful.

  The possibility of using cells from the testes as an alternative to embryonic stem cells for therapy is intriguing

Scientists already knew certain cells in the testes of newborn mice were able, like embryonic stem cells, to generate numerous different tissue types.

But until now they had not been able to show the same cells existed in adults."

http://news.bbc.co.uk/1/hi/health/4841786.stm
 

Offline JimBob

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From http://www.eurekalert.org/pub_releases/2006-04/iodp-spf041906.php

Public release date: 20-Apr-2006

Contact: Nancy Light
nlight@iodp.org
202-465-7511
Integrated Ocean Drilling Program Management International

Scientists penetrate fossil magma chamber beneath intact ocean crust



-- achieving scientific 'first'
PACIFIC OCEAN, approximately 800 km west of Costa Rica¡ªAn international team of scientists aboard the research drilling ship JOIDES Resolution has¡--for the first time¡--recovered black rocks known as gabbros from intact ocean crust. Supported by the Integrated Ocean Drilling Program (IODP), the scientists drilled through the volcanic rock that forms the Earth's crust to reach a fossil magma chamber lying 1.4 kilometers beneath the seafloor.

"By sampling a complete section of the upper oceanic crust, we've achieved a goal scientists have pursued for over 40 years, since the days of Project MoHole," says Damon Teagle, National Oceanography Centre, University of Southampton, UK, and co-chief scientist of this drilling expedition. "Our accomplishment will ultimately help science answer the important question, 'how is new ocean crust formed?'"

Formation of ocean crust is a key process in the cycle of plate tectonics; it constantly 'repaves' the Earth's surface, builds mountains, and leads to earthquakes and volcanoes. Project MoHole, begun in the 1950s, aimed to drill all the way through the ocean crust, into the Earth's mantle.

Jeffrey Alt of the University of Michigan and co-chief scientist on an earlier leg of this mission, explains that "having this sample from the deep fossil magma chamber allows us to compare its composition to the overlying lavas. It will help explain," he says, "whether ocean crust, which is about six- to seven- kilometers thick, is formed from one high-level magma chamber, or from a series of stacked magma lenses." He emphasizes that "the size and geometry of the melt lens affects not only the composition and thermal structure of the ocean crust, but also the vigor of hydrothermal circulation of seawater through the crust." Alt states that such systems lead to spectacular black-smoker vents--modern analogs of ancient copper deposits and deep-ocean oases that support exotic life.

IODP Program Director James Allan at the U.S. National Science Foundation, which co-funds IODP research with Japan, further clarifies what the expedition's discovery represents. "These results," he says, "coming from the structural heart of Pacific crust, confirm ideas from seismologic interpretation about how fast-spreading oceanic crust is built. They refine our understanding of the relationship between seismic velocity and crustal rock composition, and open new vistas for investigating the origin of lower oceanic crust, best addressed by deeper drilling." NSF and Japan each provide a scientific drilling vessel to IODP for research teams.

Geophysical theories have long projected that oceanic magma chambers freeze to form coarse-grained, black rocks known as gabbros, commonly used for facing stones on buildings and kitchen countertops. Although gabbros have been sampled elsewhere in the oceans, where faulting and tectonic movement have brought them closer to the seafloor, this is the first time that gabbros have been recovered from intact ocean crust.

"Drilling this deep hole in the eastern Pacific is a rare opportunity to calibrate remote geophysical measurements such as seismic travel time or magnetic field with direct observations of real rocks," says geophysicist Doug Wilson, University of California, Santa Barbara. Co-chief scientist on an earlier expedition to the same drilling site, Wilson was instrumental in helping to select the site drilled. His contributed to the research mission thorough study of the ocean crust's magnetic properties.

"Finding the right place to drill was probably key to our success," Wilson asserts. The research team identified a 15-million-year-old region of the Pacific Ocean that formed when the East Pacific Rise was spreading at a 'superfast' rate (more than 200 millimeters per year), faster than any mid-ocean ridge on Earth today. "We planned to exploit a partially tested geophysical observation that magma chambers should be closest to the Earth's surface, in crust formed at the fastest spreading rate. If that theory were to be correct," reasoned Wilson, "then we should only need to drill a relatively shallow hole--compared to anywhere else--to reach gabbros." Wilson and colleagues proved the theory correct.

Following three years of research and multiple trips to the site in question, the borehole that rendered the magma chamber is now more than 1,500 meters deep; it took nearly five months at sea to drill. Twenty-five hardened steel and tungsten carbide drill bits were used before the scientists' work was complete. The rocks directly above the frozen magma chamber were extremely hard because they had been baked by the underlying magmas, much like tempered steel.

IODP scientists want to return to the site of the unearthed magma chamber to explore deeper, in hopes of finding more secrets hidden deep within the ocean's crust.

###


The Integrated Ocean Drilling Program (IODP) is an international marine research program dedicated to advancing scientific understanding of the Earth, the deep biosphere, climate change, and Earth processes by sampling and monitoring sub-seafloor environments. IODP is supported by two lead agencies: the U.S. National Science Foundation, and Japan's Ministry of Education, Culture, Sports, Science, and Technology, with support from a European consortium of 17 countries, and the People's Republic of China. IODP's U.S.-sponsored drilling operations are conducted by the JOI Alliance; comprised of the Joint Oceanographic Institutions, Texas A & M University Research Foundation, and Lamont-Doherty Earth Observatory of Columbia University.

To access a list of research participants on IODP Expedition 312 and the countries they represent, or to see photos from the expedition, go to http://iodp.tamu.edu/scienceops/expeditions/exp312.html.

Note to Editors: A paper authored by the IODP research party is to be published online in Science Express on April 20, 2006. To obtain a copy of the embargoed paper, contact AAAS Office of Public Programs, +1-202-326-6440 or scipak@aaas.org

CONTACTS:

Nancy Light, IODP Management International
Tel: 202-465-7511, 202-361-3325

Jon Corsiglia, Joint Oceanographic Institutions, JOI Alliance
Tel: 202-232-3900 ext. 1644

Cheryl Dybas, U.S. National Science Foundation
Tel: 703-292-7734



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Offline Ophiolite

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As you can tell from my user name JimBob, this interests me. Thank you for posting it.

Observe; collate; conjecture; analyse; hypothesise; test; validate; theorise. Repeat until complete.
 

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MRI helps spot problems before birth
21/04/2006 3:59:24 PM  

Some infants and their families in Alberta are benefiting from the use of MRIs to catch problems before birth.

"An ultrasound just has limits on the type of detailed picture it can obtain," said Dr. Radha Chari, a professor at the University of Alberta's faculty of medicine. "The MRI seems better for us to define things a little bit better."

Chari uses MRIs to help prepare for births that are high-risk.

In the case of six-month-old Taliesin Schultz, doctors in the rural community of Barrhead first spotted a problem with his lungs when his mother had an ultrasound.

She was sent to Edmonton's Royal Alexandra Hospital for an MRI, which allowed the medical team to take a closer look at the spot on the lungs.

"There was a few times that we were considering the fact that we might not ever be able to see him," recalled Taliesin's father, Rick Shultz.

MRI is particularly useful for monitoring how the lungs of a fetus are developing.

For Taliesin, radiologist Dr. Ravi Bhargava was able to determine what was causing the mass in the baby's chest. Taliesin's lungs repaired themselves and he was born without complications.

But if the cyst is larger or the abnormality is different then a child may need surgery after birth, the doctor said.

Knowing what treatment the baby will need ahead of time allows doctors to prepare resources for the child's family, such as counselling or the services of a specialist.

Parents may also learn the location of delivery and its timing beforehand.

Chari and Bhargava first started using the technology several years ago as part of a study on fetal lung development. MRIs are now used for about one in 100 high-risk pregnancies at the hospital.

The results of the study helped to set new standards for lung development for 16- to 40-week-old fetuses, which were published in the journal Radiology.

http://www.cbc.ca

My Question to you is- Isnt radiology (Xrays) toxic to a developing feuts? Why subjec high risk babies to more risks??

-Meg
« Last Edit: 24/04/2006 14:14:31 by elegantlywasted »
 

ROBERT

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quote:
Originally posted by elegantlywasted

MRI helps spot problems before birth
21/04/2006 3:59:24 PM  

Some infants and their families in Alberta are benefiting from the use of MRIs to catch problems before birth.

http://www.cbc.ca

My Question to you is- Isnt radiology (Xrays) toxic to a developing feuts? Why subjec high risk babies to more risks??

-Meg



Hi Meg,
MRIs do not use X-rays, they use radio waves and a strong magnetic field:-

"  The Basic Idea
If you have ever seen an MRI machine, you know that the basic design used in most is a giant cube. The cube in a typical system might be 7 feet tall by 7 feet wide by 10 feet long (2 m by 2 m by 3 m), although new models are rapidly shrinking. There is a horizontal tube running through the magnet from front to back. This tube is known as the bore of the magnet. The patient, lying on his or her back, slides into the bore on a special table. Whether or not the patient goes in head first or feet first, as well as how far in the magnet they will go, is determined by the type of exam to be performed. MRI scanners vary in size and shape, and newer models have some degree of openness around the sides, but the basic design is the same. Once the body part to be scanned is in the exact center or isocenter of the magnetic field, the scan can begin.
In conjunction with radio wave pulses of energy, the MRI scanner can pick out a very small point inside the patient's body and ask it, essentially, "What type of tissue are you?" The point might be a cube that is half a millimeter on each side. The MRI system goes through the patient's body point by point, building up a 2-D or 3-D map of tissue types. It then integrates all of this information together to create 2-D images or 3-D models. "
http://electronics.howstuffworks.com/mri1.htm

 
 
« Last Edit: 24/04/2006 17:10:54 by ROBERT »
 

Offline neilep

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Hominid fossils from Ethiopia link ape-men to more distant human ancestors

Berkeley -- New fossils discovered in the Afar desert of eastern
Ethiopia are a missing link between our ape-man ancestors some 3.5
million years ago and more primitive hominids a million years older,
according to an international team led by the University of
California, Berkeley, and Los Alamos National Laboratory in New
Mexico.


The fossils are from the most primitive species of Australopithecus,
 known as Au. anamensis, and date from about 4.1 million years ago,
 said Tim White, a UC Berkeley professor of integrative biology and
one of the team's leaders. The hominid Australopithecus has often
been called an ape-man because, though short-statured, small-brained
and big-toothed, it walked on two legs unlike the great apes.


More primitive hominids in the genus Ardipithecus date from between
4.4 million and 7 million years ago and were much more ape-like,
though they, too, walked on two legs.


"This new discovery closes the gap between the fully blown
Australopithecines and earlier forms we call Ardipithecus," White
said. "We now know where Australopithecus came from before 4 million
years ago."


The fossil finds and an analysis of the hominid's habitat and
evolutionary position are reported by White and co-authors from
Ethiopia, Japan, France and the United States in the April 13 issue
of Nature.


Since the first Australopithecus skull, the famous Taung child, was
discovered in South Africa 82 years ago by Raymond Dart, fossils of
this hominid have been found all over eastern Africa spanning a 3-
million-year time period. Seven separate species have been named,
including the most primitive, Au. anamensis, which dates from 4.2
million years ago, and Au. africanus, Dart's find. The most
specialized species, Au. boisei, died out about 1.2 million years
ago, long after the genus Homo had spread throughout the Old World.


The most famous of the Australopithecine fossils was "Lucy," a 3.5-
foot adult skeleton discovered in the Afar depression in 1974. Her
analytical team included White. Subsequently named Au. afarensis,
this hominid, which lived between 3.6 and 3 million years ago, was
also discovered in the Middle Awash study area, where the new Au.
anamensis fossils were found.


Ardipithecus, on the other hand, was discovered by White and his
team in 1992, based on fossils from Aramis, a village in the Awash
Valley of Ethiopia's Afar rift. White and his team named the 4. 4
million-year-old fossils Ardipithecus ramidus.


The relationship between Australopithecus and Ardipithecus remained
unclear, however, because of a million-year gap between these two
genera. The new fossil finds, jawbones and teeth from each of two
localities, bridge that gap. With Ardipithecus in older rocks and
Au. afarensis in overlying rocks, the newly announced fossils are
intermediate in time and anatomy.


The teeth tell a story about the organism's diet, White said.
Australopithecus's large cheek teeth - anthropologists refer to the
hominid as a megadont, meaning large-toothed - allowed it to subsist
on a broader diet of tough, fibrous plants. The teeth of
Ardipithecus were smaller, restricting it to a diet of softer, less
abrasive food, White said.


"Australopithecus became a superior omnivore, able to eat tubers and
roots with more fiber and grit, adapting it better to times of
scarcity during periods of extended drought," he said. "They may
have been small brained, but they stuck around a long time, fully
half of our zoological family's 6-million-year existence on the
planet."


White and his Middle Awash team are cautious about claiming that the
new fossils are closely related to the most recent member of the
genus Ardipithecus, Ar. ramidus, since the two are separated by only
300,000 years. While Au. anamensis could have rapidly evolved from
Ar. ramidus, contemporary fossils may yet be found. Nevertheless,
White said, the new fossils show clear descent from the genus
Ardipithecus, two species of which have been identified over the
genus's 2 million years of existence. The fact that fossils of Ar.
ramidus, Au. anamensis and Au. afarensis have been found in
successive sediment layers in the same area of the Middle Awash site
also indicates an evolutionary sequence, said White.


"It is fair to say that some species of Ardipithecus gave rise to
Australopithecus," he said.


The first of the newly reported fossils, an upper jawbone with
teeth, was discovered in November 1994 at Aramis, the site of
earlier fossil finds of Au. anamensis. In 2000, 2003 and again in
both January and December 2005, the team found additional teeth and
jaw fragments at Asa Issie, about 10 kilometers west of Aramis. Many
of the teeth were completely shattered, but by water-sieving the
surface sediments, they were able to collect nearly all the
fragments, which White painstakingly reassembled.


In all, teeth and jawbones of eight individuals were found at Asa
Issie, all from about 4.1 million years ago as dated by
paleomagnetic and argon-argon methods by a team led by geologist
Paul Renne, UC Berkeley adjunct professor of earth and planetary
science and director of the independent Berkeley Geochronology
Center. A partial thigh bone and hand and foot bones were very
similar to the Lucy bones found 60 kilometers away in Hadar and
dating from 3 million to 3.4 million years ago. The large, thick
-enameled teeth were judged by the research team to be closest to
Au. anamensis, and ancestral to Au. afarensis.


Hundreds of mammal fossils also were found, allowing the team to
reconstruct the habitat as closed woodland with lots of colobus
monkeys, kudus, pigs, birds and rodents, as well as a collection of
carnivores, primarily hyenas and big cats.


"The abundance of monkeys, kudus and other mammals, and petrified
wood found both at Aramis and Asa Issie shows that a closed, wooded
habitat type persisted over a long period in this part of the Afar
and was favored by early hominids between 4 and 6 million years
ago," said Giday WoldeGabriel of Los Alamos National Laboratory, a
geologist and co-leader of the Middle Awash project.


The Middle Awash team, consisting of 60 scientists from 17
countries, brings expertise in geology, archaeology, paleontology
and evolutionary biology to the study of fossils unearthed in
Ethiopia spanning nearly 6 million years of evolution - from the
first hominids that split from chimpanzees to modern humans, Homo
sapiens sapiens. The team continues to unearth fossils from what
White describes as "the world's best window on human evolution."


SOURCE:EUREKERALERT.ORG

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Offline neilep

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Apollo lunar rocks suggest meteorite shower
OREGON STATE UNIVERSITY NEWS RELEASE


New age measurements of lunar rocks returned by the Apollo space missions have revealed that a surprising number of the rocks show signs of melting about 3.9 billion years ago, suggesting that the moon - and its nearby neighbor Earth - were bombarded by a series of large meteorites at that time.

The idea that meteorites have hammered the moon's surface isn't news to scientists. The lunar surface is pock-marked with large craters carved out by the impact of crashing asteroids and meteorites, said Robert Duncan, a professor and associate dean in the College of Oceanic and Atmospheric Sciences at Oregon State University.

But the narrow range of the impact dates suggests to researchers that a large spike in meteorite activity took place during a 100-million year interval - possibly the result of collisions in the asteroid belt with comets coming from just beyond our solar system.

Results of the study are being published in Geochimica et Cosmochimica Acta, the journal of the international Meteoritical Society. Co-authors with Duncan are Marc Norman of the Australian National University and John Huard, also an oceanographer at OSU. The study was funded by NASA.

Tiny melted fragments from the lunar rocks were dated at the noble gas geochronology laboratory at Oregon State. Duncan and Huard were able to use radiometric dating techniques to determine when the rocks had melted after being struck by meteorites. What is particularly intriguing, Duncan says, is that this apparent spike in meteorite activity took place about 3.8 to 4 billion years ago - an era that roughly coincides with when scientists believe life first began on Earth, as evidenced by the fossil record of primitive one-cell bacteria.

It is possible that life was introduced to Earth from one of these meteorites, Duncan said. Or it could have developed spontaneously once the bombardment subsided, or developed beneath the ocean near life-nurturing hydrothermal vents. The lack of evidence on Earth makes the analysis of moon rocks much more compelling. The meteorite activity that bombarded the moon likely struck our planet as well.

"Unfortunately, we haven't found many very old rocks on Earth because of our planet's surface is constantly renewed by plate tectonics, coupled with erosion," Duncan said. "By comparison, the moon is dead, has no atmosphere and provides a record of meteorite bombardment that we can only assume is similar to that on Earth."

When the solar system was formed, scientists say, it spun away from the sun like a huge, hot disk that subsequently condensed into planets. At least nine planets survived, sucking in loose space matter from around them. Those planets closer to the sun were more solid, while those farther away were comprised primarily of gases.

Over time, the space debris has lessened, either being gravitationally collected into the planets, or smashed into cosmic dust through collisions with other objects. The discovery of this apparent spike in meteorite activity suggests to the authors that a major event took place.

"We may have had a 10th and 11th planet that collided," Duncan said, "or it's possible that the outward migration of Neptune may have scattered comets and small planet bodies, inducing collisions in the asteroid belt. The close passing of a neighboring star could have had a similar effect."

Duncan and his colleagues examined about 50 different rock samples scooped up by astronauts on the Apollo missions. All but a few of them produced ages close to 3.9 billion years and they exhibited different chemical "fingerprints," indicating that they had melted from different meteorites and lunar surface rocks.

"The evidence is clear that there was repeated bombardment by meteorites," Duncan said.

When meteorites collide with the moon, the surface rock and the meteorites partially melt, and then turn to glass. After the glasses quenched, they slowly began to accumulate argon gas that scientists can measure and calculate from the known isotopic decay rate (from potassium) to determine age.

"The formation of glass from the melting is like starting a clock," Duncan said. "It resets the time for us to determine billions of years later."

Duncan and his colleagues say the intense bombardment ended about 3.85 billion years ago, and there has been a slowly declining pattern of meteorite activity since. Many of the prominent craters found on the moon date back to that era, including Imbrium, at 3.84 billion years; Serenitatis, 3.89 billion years; and Nectaris, 3.92 billion years.

Many of the moon's craters are 10 to 100 kilometers across and scientists say that meteorites of that size or larger may have struck the Earth in the past. Such meteorites impacts may have been responsible for the extinction of dinosaurs 65 million years ago, and a mass extinction that wiped out an estimated 75 percent of the Earth's plant and animal species 250 million years ago.

However, Duncan said, these mass extinctions could also be linked to climate, disease and volcanism - or a combination of such factors.

"It is clear that there was a spike of meteorite activity on the moon about 3.9 billion years ago, and that it lasted for roughly 100 million years," Duncan said. "The moon provides important information about the early history of our solar system that is missing from the Earth's geologic record."

SOURCE: SPACEFLIGHTNOW.COM

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Mobile DNA part of evolution's toolbox
The repeated copying of a small segment of DNA in the genome of a primeval fish may have been crucial to the transition of ancient animals from sea to land, or to later key evolutionary changes in land vertebrates. The discovery is "tantalizing evidence" that copied DNA elements known as retroposons could be an important source of evolutionary innovations, says the director of the research, Howard Hughes Medical Institute investigator David Haussler.
"The big question is whether this is a special case or whether it's the tip of the iceberg," says Haussler, who is at the University of California, Santa Cruz. A report on the research is published in the May 4, 2006, issue of the journal Nature.

Haussler and his colleagues were led to the discovery through their work on what they call "ultraconserved elements" -- segments of DNA hundreds of nucleotides long that are almost exactly the same in a wide variety of vertebrate organisms. Haussler and postdoctoral fellow Gill Bejerano discovered the ultraconserved elements in 2003, and since then they have been trying to figure out how they arose and what function they serve.

One ultraconserved element in particular caught their eye. "We were very interested in this sequence, because it had a number of copies elsewhere in the genome," says Bejerano, who is the first author of the study. Close copies of the sequence were ubiquitous in amphibians, birds, and mammals, indicating that it served an important function. "We found it in every species for which we have genomes, from frogs to humans," says Bejerano.

Comparing the sequence to other species also turned up a big surprise. When the researchers compared the human ultraconserved element to all the DNA sequences in the public database GenBank, the closest match was to DNA from the coelacanth -- an ancient fish thought to have gone extinct millions of years ago until a live specimen was caught in 1938 off the east coast of South Africa. The coelacanth is a descendant of the ancient marine organism that gave rise to the terrestrial vertebrates more than 360 million years ago. Humans are therefore separated from the coelacanth by hundreds of millions of years of evolution, yet the two organisms still share critical DNA sequences.

In the coelacanth, the ultraconserved segments were produced by a retroposon known as a short interspersed repetitive element, or SINE, which is a piece of DNA that can make copies of itself and insert those copies elsewhere in an organism's genome. Haussler and his colleagues called this SINE the LF-SINE, where LF stands for lobe-finned fishes--the group of fishes that gave rise to both the coelacanth and terrestrial vertebrates.

The LF-SINE was very active in the evolutionary lineage leading to the terrestrial vertebrates, but much less active after animals moved onto land. Humans have 245 recognizable copies of the LF-SINE, most or all of which probably were in place before the origins of the mammals. But in the lineage leading to the coelacanth, the LF-SINE remained active, so that the coelacanth genome is now estimated to contain hundreds of thousands of copies of the sequence.

The close copies of the ultraconserved element scattered around vertebrate genomes have changed less than would be expected over evolutionary time, indicating that they are functionally important. But relatively few of the copies contain parts that code for proteins, which suggests they instead are helping to regulate when genes are turned on and off. Furthermore, when Bejerano analyzed the locations of the copies, he found that they tended to be near genes that control the development of the brain.

Haussler and his colleagues then looked at a particular example -- a copy of the ultraconserved element that is near a gene called Islet 1 (ISL1). ISL1 produces a protein that helps control the growth and differentiation of motor neurons. In the laboratory of Edward Rubin at the University of California, Berkeley, postdoctoral fellow Nadav Ahituv combined the human version of the LF-SINE sequence with a "reporter" gene that would produce an easily recognizable protein if the LF-SINE were serving as its on-off switch. He then injected the resulting DNA into the nuclei of fertilized mouse eggs. Eleven days later, he examined the mouse embryos to see whether and where the reporter gene was switched on. Sure enough, the gene was active in the embryos' developing nervous systems, as would be expected if the LF-SINE copy were regulating the activity of ISL1.

The discoverer of mobile DNA elements, Barbara McClintock, suggested in 1950 that they might play a role in the regulation of genes -- a hypothesis that was more fully developed by Roy Britten and Eric Davidson in about 1970, when it was discovered that more than half of the human genome consists of remnants of mobile elements. But the mechanisms underlying this process remained obscure. Haussler's work provides direct evidence that even when they land at some distance from a gene, mobile elements like SINEs can be adapted to serve as regulatory elements that have powerful effects in their new locations. "When you activate a gene in a new context," Bejerano points out, "you get processes that did not occur before."

Bejerano and Haussler's results support the hypothesis that the movement of retroposons can generate evolutionary experiments by adding new regulatory modules to genes. Most of these experiments will have no effects or will harm an organism. But every once in a while, the movement of a regulatory element will give an organism an evolutionary advantage. "And to the extent that [such changes] improve the fitness of an organism," says Haussler, "they eventually will become fixed in a population."

"This suggests a lot of exciting evolutionary avenues," says Haussler, "but we don't yet know how prevalent this kind of evolution is." Other labs have found similar examples of mobile elements that have changed the regulation of genes, and Haussler expects the number of reports to grow. "It's a very exciting time to be looking at the human genome, because there's an enormous amount of DNA that we know is important, but we don't yet know what it's doing."

SOURCE: EUREKALERT


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World-leading microscope shows more detail than ever


A unique 3-dimensional microscope that works in a new way is giving unprecedented insight into microscopic internal structure and chemical composition. It is revealing how materials are affected, over time, by changes in temperature, humidity, weight load and other conditions.
The device could lead to advances in a range of areas, such as healthcare (in furthering, for instance, the understanding of conditions such as osteoporosis), the development of better construction materials, improved oil extraction methods and even the study of fossils.

Like a number of other microscopes, the new microscope harnesses X-rays to provide information about an object's internal structure down to micron scale. (A micron is a millionth of a metre.) What makes it unique, however, is its innovative use of a technique called 'time delay integration', which enables it to generate much better images of larger objects than any other device. This means that microscopic structure can be studied with greater accuracy.

With EPSRC funding, a multi-disciplinary team drawn from six UK universities has been developing and utilising the microscope, which, although similar to the CT scanners used in healthcare, can view things in much greater detail.

X-ray microscopes can produce 3-d internal pictures of an object by taking a large number of 2-d images from different angles – this is known as X-ray microtomography. However, the new microscope's combining of this technique with time delay integration is completely unique. Through averaging out imperfections in the image across all pixels, this approach enables the microscope to produce clearer and bigger pictures than previously possible (see 'Notes for Editors').

Some of the microscope's many potential uses include:

Studying how bone and tooth tissue behave in conditions such as osteoporosis, osteoarthritis and tooth decay. By improving understanding of these conditions, the microscope could aid prevention, earlier diagnosis and more effective treatment.
Observing how crude oil is held in sandstone pores. This knowledge could assist the development of more efficient ways of exploiting both offshore and onshore oil resources.
Investigating the mechanical behaviour of metals at a microscopic level. This could contribute to development of more reliable, more resilient and lower weight materials for use in construction, aviation and the storage & transportation of dangerous substances.
Detailed study of fossils embedded in rocks without having to remove and risk damaging them.
Professor Jim Elliott of Queen Mary, University of London led the project. "As well as developing these microscopes to study subtle variations in internal structure, a main aim of ours is to work with the wider scientific community to identify problems where they could make a real contribution," he says. "There's no limit to what it would be useful or interesting to look at."

The microscope looks set to be a valuable research tool that many different organisations in a wide range of sectors could benefit from using. The team is currently planning to seek funding to support the development of a radical new design that could be even more effective.

SOURCE: EUREKALERT


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Man may have caused pre-historic extinctions

New research shows that pre-historic horses in Alaska may have been hunted into extinction by man, rather than by climate change as previously thought.

The discovery by Andrew Solow of Woods Hole Oceanographic Institute, US, David Roberts of the Royal Botanic Garden, Kew and Karen Robbirt of the University of East Anglia (UEA) is published this week in Proceedings of the National Academy of Sciences (PNAS).

The accepted view had previously been that the wild horses became extinct long before the extinction of mammoths and the arrival of humans from Asia - ruling out the possibility that they were over-hunted by man. One theory had been that a period of climate cooling wiped them out.

However, the researchers have discovered that uncertainties in dating fossil remains and the incompleteness of fossil records mean that the survival of the horse beyond the arrival of humans cannot be ruled out.

The PNAS paper develops a new statistical method to help resolve the inherent problems associated with dating fossils from the Pleistocene period. The aim is to provide a far more accurate timetable for the extinction of caballoid horses and mammoths and, ultimately, the cause.

"This research is exciting because it throws open the debate as to whether climate change or over-hunting may have led to the extinction of pre-historic horses in North America," said UEA's Karen Robbirt.

The Pleistocene period refers to the first epoch of the Quarternary period between 1.64 million and 10,000 years ago. It was characterised by extensive glaciation of the northern hemisphere and the evolution of modern man around 100,000 years ago.

It is known that the end of the Pleistocene period was a time of large-scale extinctions of animals and plants in North America and elsewhere but the factors responsible have remained open to question, with climate change and over-hunting by humans the prime suspects. Ends

SOURCE: EUREKALERT.

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Last Update: Tuesday, May 9, 2006. 9:00am (AEST)
New neighbours: Two dwarf galaxies have been found near the Milky Way. [File photo]

New neighbours: Two dwarf galaxies have been found near the Milky Way. [File photo] (Reuters)
   
Astronomers spy two dwarf galaxies

Two dim dwarf galaxies are the Milky Way's newest known galactic companions, astronomers studying a vast swath of the sky say.

This brings the total number of dwarf galaxies in the Milky Way's cosmic neighbourhood to 14, but theorists believe there could conceivably be hundreds more.

Scientists studying the Sloan Digital Sky Survey say the two newly-detected dwarfs have been found in the direction of the constellations Canes Venatici (the hunting dogs) and Bootes (the herdsman).

The little galaxy found in Canes Venatici is about 640,000 light years from the sun, a stone's throw in cosmic terms.

A light year is about 10 trillion kilometres, the distance light travels in a year.

The dwarf found in Bootes is about the same distance from the sun.

Even though they are close, the galaxies are hard to spot because they are so dim, a defining characteristic of dwarf galaxies.

The new galaxy in Bootes is the faintest discovered, with a total luminosity of 100,000 suns.
Cold dark matter

Some astronomers theorise that there should be hundreds of clumps of so-called cold dark matter - slow-moving subatomic particles left over from the earliest period of the universe - orbiting the Milky Way, which contains earth.

Each of these clumps should be massive enough to host a dwarf galaxy, but so far only 14 have been found.

The two newest discoveries are among 12 spheroidal dwarf galaxies, two more are the Large Magellanic Cloud and the Small Magellanic Cloud, a pair of irregular dwarfs.

A galaxy is considered a dwarf if it is less than 10 per cent as luminous as the Milky Way, since luminosity is mostly a matter of the total number of stars.

The Sloan Digital Sky Survey, which is managed by a global consortium of museums, universities and other astronomical institutions, aims to ultimately provide detailed images of more than one-quarter of the sky for use by the scientists.

- Reuters

URL = http://www.abc.net.au/news/newsitems/200605/s1633825.htm



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Dragonfly migration resembles that of birds, scientists say.

Princeton, N.J. - Scientists have discovered that migrating dragonflies and songbirds exhibit many of the same behaviors, suggesting the rules that govern such long-distance travel may be simpler and more ancient than was once thought.

The research, published in the May 11 Biology Letters, is based on data generated by tracking 14 green darner dragonflies with radio transmitters weighing only 300 milligrams -- about a third as much as a paper clip. Green darners are among the 25 to 50 species of dragonflies thought to be migratory among about 5200 species worldwide.

The team of researchers that made the discovery, led by Princeton University's Martin Wikelski, tracked the insects for up to 10 days from both aircraft and handheld devices on the ground. They found that the dragonflies' flight patterns showed many similarities to those of birds that migrate over the same regions of coastal New Jersey.

"The dragonflies' routes have showed distinct stopover and migration days, just as the birds' did," said Wikelski, an associate professor of ecology and evolutionary biology. "Additionally, groups of both birds and dragonflies did not migrate on very windy days and only moved after two successive nights of falling temperatures. We saw other similarities as well, which makes us wonder just how far back in Earth's history the rules for migration were established in its animals."

According to fossil records, dragonflies appeared about 285 million years ago, predating the first birds by about 140 million years.

Wikelski said that the findings could also be an important demonstration of how to track small animals over great distances, a technique that could be useful in agriculture and ecological management.

"These small transmitters could enable us to track animals from space all around the globe if satellites were available," Wikelski said. "Though nearly everyone has heard of animal migration, we actually know very little about how animals move. It could tell us a lot about the way species respond to climate change and other disturbances. Because the economies of many nations are still largely agrarian, a better understanding of how, say, locust swarms travel could assist us with managing both local agriculture and the world economy that hinges upon it."

SOURCE: EUREKALERT.ORG

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We will be able to live to 1,000'
By Dr Aubrey de Grey
University of Cambridge

Life expectancy is increasing in the developed world. But Cambridge University geneticist Aubrey de Grey believes it will soon extend dramatically to 1,000. Here, he explains why.

Ageing is a physical phenomenon happening to our bodies, so at some point in the future, as medicine becomes more and more powerful, we will inevitably be able to address ageing just as effectively as we address many diseases today.

I claim that we are close to that point because of the SENS (Strategies for Engineered Negligible Senescence) project to prevent and cure ageing.

It is not just an idea: it's a very detailed plan to repair all the types of molecular and cellular damage that happen to us over time.

And each method to do this is either already working in a preliminary form (in clinical trials) or is based on technologies that already exist and just need to be combined.

This means that all parts of the project should be fully working in mice within just 10 years and we might take only another 10 years to get them all working in humans.

When we get these therapies, we will no longer all get frail and decrepit and dependent as we get older, and eventually succumb to the innumerable ghastly progressive diseases of old age.

We will still die, of course - from crossing the road carelessly, being bitten by snakes, catching a new flu variant etcetera - but not in the drawn-out way in which most of us die at present.

 So, will this happen in time for some people alive today? Probably. Since these therapies repair accumulated damage, they are applicable to people in middle age or older who have a fair amount of that damage.

I think the first person to live to 1,000 might be 60 already.

It is very complicated, because ageing is. There are seven major types of molecular and cellular damage that eventually become bad for us - including cells being lost without replacement and mutations in our chromosomes.

Each of these things is potentially fixable by technology that either already exists or is in active development.

'Youthful not frail'

The length of life will be much more variable than now, when most people die at a narrow range of ages (65 to 90 or so), because people won't be getting frailer as time passes.

The average age will be in the region of a few thousand years. These numbers are guesses, of course, but they're guided by the rate at which the young die these days.

If you are a reasonably risk-aware teenager today in an affluent, non-violent neighbourhood, you have a risk of dying in the next year of well under one in 1,000, which means that if you stayed that way forever you would have a 50/50 chance of living to over 1,000.

And remember, none of that time would be lived in frailty and debility and dependence - you would be youthful, both physically and mentally, right up to the day you mis-time the speed of that oncoming lorry.

Should we cure ageing?

Curing ageing will change society in innumerable ways. Some people are so scared of this that they think we should accept ageing as it is.

I think that is diabolical - it says we should deny people the right to life.

The right to choose to live or to die is the most fundamental right there is; conversely, the duty to give others that opportunity to the best of our ability is the most fundamental duty there is.

There is no difference between saving lives and extending lives, because in both cases we are giving people the chance of more life. To say that we shouldn't cure ageing is ageism, saying that old people are unworthy of medical care.

Playing God?

People also say we will get terribly bored but I say we will have the resources to improve everyone's ability to get the most out of life.

People with a good education and the time to use it never get bored today and can't imagine ever running out of new things they'd like to do.

And finally some people are worried that it would mean playing God and going against nature. But it's unnatural for us to accept the world as we find it.

Ever since we invented fire and the wheel, we've been demonstrating both our ability and our inherent desire to fix things that we don't like about ourselves and our environment.

We would be going against that most fundamental aspect of what it is to be human if we decided that something so horrible as everyone getting frail and decrepit and dependent was something we should live with forever.

If changing our world is playing God, it is just one more way in which God made us in His image.

SOURCE: story from BBC NEWS:
http://news.bbc.co.uk/go/pr/fr/-/1/hi/uk/4003063.stm

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Light's most exotic trick yet: So fast it goes ... backwards?
UNIVERSITY OF ROCHESTER NEWS RELEASE
Posted: May 14, 2006

In the past few years, scientists have found ways to make light go both faster and slower than its usual speed limit, but now researchers at the University of Rochester published a paper on May 12 in Science on how they've gone one step further: pushing light into reverse. As if to defy common sense, the backward-moving pulse of light travels faster than light.

Confused? You're not alone.

"I've had some of the world's experts scratching their heads over this one," says Robert Boyd, the M. Parker Givens Professor of Optics at the University of Rochester. "Theory predicted that we could send light backwards, but nobody knew if the theory would hold up or even if it could be observed in laboratory conditions."

Boyd recently showed how he can slow down a pulse of light to slower than an airplane, or speed it up faster than its breakneck pace, using exotic techniques and materials. But he's now taken what was once just a mathematical oddity-negative speed-and shown it working in the real world.

"It's weird stuff," says Boyd. "We sent a pulse through an optical fiber, and before its peak even entered the fiber, it was exiting the other end. Through experiments we were able to see that the pulse inside the fiber was actually moving backward, linking the input and output pulses."

So, wouldn't Einstein shake a finger at all these strange goings-on? After all, this seems to violate Einstein's sacred tenet that nothing can travel faster than the speed of light.

"Einstein said information can't travel faster than light, and in this case, as with all fast-light experiments, no information is truly moving faster than light," says Boyd. "The pulse of light is shaped like a hump with a peak and long leading and trailing edges. The leading edge carries with it all the information about the pulse and enters the fiber first. By the time the peak enters the fiber, the leading edge is already well ahead, exiting. From the information in that leading edge, the fiber essentially 'reconstructs' the pulse at the far end, sending one version out the fiber, and another backward toward the beginning of the fiber."

Boyd is already working on ways to see what will happen if he can design a pulse without a leading edge. Einstein says the entire faster-than-light and reverse-light phenomena will disappear. Boyd is eager to put Einstein to the test.

So how does light go backwards?

Boyd, along with Rochester graduate students George M. Gehring and Aaron Schweinsberg, and undergraduates Christopher Barsi of Manhattan College and Natalie Kostinski of the University of Michigan, sent a burst of laser light through an optical fiber that had been laced with the element erbium. As the pulse exited the laser, it was split into two. One pulse went into the erbium fiber and the second traveled along undisturbed as a reference. The peak of the pulse emerged from the other end of the fiber before the peak entered the front of the fiber, and well ahead of the peak of the reference pulse.

But to find out if the pulse was truly traveling backward within the fiber, Boyd and his students had to cut back the fiber every few inches and re-measure the pulse peaks when they exited each pared-back section of the fiber. By arranging that data and playing it back in a time sequence, Boyd was able to depict, for the first time, that the pulse of light was moving backward within the fiber.

To understand how light's speed can be manipulated, think of a funhouse mirror that makes you look fatter. As you first walk by the mirror, you look normal, but as you pass the curved portion in the center, your reflection stretches, with the far edge seeming to leap ahead of you (the reference walker) for a moment. In the same way, a pulse of light fired through special materials moves at normal speed until it hits the substance, where it is stretched out to reach and exit the material's other side.

Conversely, if the funhouse mirror were the kind that made you look skinny, your reflection would appear to suddenly squish together, with the leading edge of your reflection slowing as you passed the curved section. Similarly, a light pulse can be made to contract and slow inside a material, exiting the other side much later than it naturally would.

To visualize Boyd's reverse-traveling light pulse, replace the mirror with a big-screen TV and video camera. As you may have noticed when passing such a display in an electronics store window, as you walk past the camera, your on-screen image appears on the far side of the TV. It walks toward you, passes you in the middle, and continues moving in the opposite direction until it exits the other side of the screen.

A negative-speed pulse of light acts much the same way. As the pulse enters the material, a second pulse appears on the far end of the fiber and flows backward. The reversed pulse not only propagates backward, but it releases a forward pulse out the far end of the fiber. In this way, the pulse that enters the front of the fiber appears out the end almost instantly, apparently traveling faster than the regular speed of light. To use the TV analogy again-it's as if you walked by the shop window, saw your image stepping toward you from the opposite edge of the TV screen, and that TV image of you created a clone at that far edge, walking in the same direction as you, several paces ahead.

"I know this all sounds weird, but this is the way the world works," says Boyd.

SOURCE:SPACEFLIGHTNOW.COM

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New scenario explains origin of Neptune's oddball moon
UNIVERSITY OF CALIFORNIA-SANTA CRUZ NEWS RELEASE
Posted: May 14, 2006

Neptune's large moon Triton may have abandoned an earlier partner to arrive in its unusual orbit around Neptune. Triton is unique among all the large moons in the solar system because it orbits Neptune in a direction opposite to the planet's rotation (a "retrograde" orbit). It is unlikely to have formed in this configuration and was probably captured from elsewhere.

In the May 11 issue of the journal Nature, planetary scientists Craig Agnor of the University of California, Santa Cruz, and Douglas Hamilton of the University of Maryland describe a new model for the capture of planetary satellites involving a three-body gravitational encounter between a binary and a planet. According to this scenario, Triton was originally a member of a binary pair of objects orbiting the Sun. Gravitational interactions during a close approach to Neptune then pulled Triton away from its binary companion to become a satellite of Neptune.

"We've found a likely solution to the long-standing problem of how Triton arrived in its peculiar orbit. In addition, this mechanism introduces a new pathway for the capture of satellites by planets that may be relevant to other objects in the solar system," said Agnor, a researcher in UCSC's Center for the Origin, Dynamics, and Evolution of Planets.

With properties similar to the planet Pluto and about 40 percent more massive, Triton has an inclined, circular orbit that lies between a group of small inner moons with prograde orbits and an outer group of small satellites with both prograde and retrograde orbits. There are other retrograde moons in the solar system, including the small outer moons of Jupiter and Saturn, but all are tiny compared to Triton (less than a few thousandths of its mass) and have much larger and more eccentric orbits about their parent planets.

Triton may have come from a binary very similar to Pluto and its moon Charon, Agnor said. Charon is relatively massive, about one-eighth the mass of Pluto, he explained.

"It's not so much that Charon orbits Pluto, but rather both move around their mutual center of mass, which lies between the two objects," Agnor said.

In a close encounter with a giant planet like Neptune, such a system can be pulled apart by the planet's gravitational forces. The orbital motion of the binary usually causes one member to move more slowly than the other. Disruption of the binary leaves each object with residual motions that can result in a permanent change of orbital companions. This mechanism, known as an exchange reaction, could have delivered Triton to any of a variety of different orbits around Neptune, Agnor said.

An earlier scenario proposed for Triton is that it may have collided with another satellite near Neptune. But this mechanism requires the object involved in the collision to be large enough to slow Triton down, but small enough not to destroy it. The probability of such a collision is extremely small, Agnor said.

Another suggestion was that aerodynamic drag from a disk of gas around Neptune slowed Triton down enough for it to be captured. But this scenario puts constraints on the timing of the capture event, which would have to occur early in Neptune's history when the planet was surrounded by a gas disk, but late enough that the gas would disperse before it slowed Triton's orbit enough to send the moon crashing into the planet.

In the past decade, many binaries have been discovered in the Kuiper belt and elsewhere in the solar system. Recent surveys indicate that about 11 percent of Kuiper belt objects are binaries, as are about 16 percent of near-Earth asteroids.

"These discoveries pointed the way to our new explanation of Triton's capture," Hamilton said. "Binaries appear to be a ubiquitous feature of small-body populations."

The Pluto/Charon pair and binaries in the Kuiper belt are especially relevant for Triton, as their orbits abut Neptune's, he said.

"Similar objects have probably been around for billions of years, and their prevalence indicates that the binary-planet encounter that we propose for Triton's capture is not particularly restrictive," Hamilton said.

The exchange reaction described by Agnor and Hamilton may have broad applications in understanding the evolution of the solar system, which contains many irregular satellites. The researchers plan to explore the implications of their findings for other satellite systems.

This research was supported by grants from NASA's Planetary Geology and Geophysics, Outer Planet Research, and Origins of Solar Systems programs.


SOURCE: SPACEFLIGHTNOW.COM

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17 May 2006
" Q. Did humans and chimps once interbreed?

Tangled family tree
 By Bob Holmes

It goes to the heart of who we are and where we came from. Our human ancestors were still interbreeding with their chimp cousins long after first splitting from the chimpanzee lineage, a genetic study suggests. Early humans and chimps may even have hybridised completely before diverging a second time. If so, some of the earliest fossils of proto-humans might represent an abortive first attempt to diverge from chimps, rather than being our direct ancestors. "
http://www.newscientist.com/article.ns?id=mg19025525.000&feedId=online-news_rss20

A. YES, look at Wayne Rooney and President George W. Bush :).

« Last Edit: 18/05/2006 14:03:39 by ROBERT »
 

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Apes shown to be able to plan ahead
Associated Press

WASHINGTON — They don't bring along an umbrella or sunglasses that might be needed later, but researchers say apes, like people, can plan ahead.

Both orangutans and bonobos were able to figure out which tool would work in an effort to retrieve grapes, and were able to remember to bring that tool along hours later, researchers report in Friday's issue of the journal Science.

In a series of laboratory tests the apes were shown the tools and grapes, allowed to retrieve grapes, and then removed from the area where the treats were available.

They were allowed back from one to 14 hours later and most were able to bring along the correct tool to get the treats, report Nicholas J. Mulcahy and Josep Call of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany.

The researchers said the finding suggests that planning ahead arose at least 14 million years ago, when the last common ancestor of bonobos, orangutans and humans lived.

While the findings do not necessarily imply that the apes are able to anticipate a future state of mind, they are nonetheless groundbreaking, Thomas Suddendorf of the University of Queensland in Australia said in a commentary.

"By identifying what capacities our closest living relatives share with us, we can get a glimpse at our evolutionary past," Suddendorf said.

In a separate paper in ScienceExpress, the electronic version of Science, researchers report that scrub jays look over their shoulders when hiding food for future use and, if they think another bird saw where they put it, will relocate their cache.

The report by Nicola S. Clayton and colleagues at the University of Cambridge in England noted that relocating food was common when a bird thought it had been observed by a more dominant bird, but not when a partner was present.

The findings indicate that the birds act to avoid the possibility that a non-partner will raid their stored food, and remember who was around when they hid it, the researchers say.

SOURCE: CTV.CA


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Polar bear + Grizzly bear = Pizzly Bear

" DNA Tests Confirm Bear Was a Hybrid

Roger Kuptana, an Inuvialuit guide from Sachs Harbour, Northwest Territories, was the first to suspect it had actually happened when he proposed that a strange-looking bear shot last month by an American sports hunter might be half polar bear, half grizzly.

Territorial officials seized the creature after noticing its white fur was scattered with brown patches and that it had the long claws and humped back of a grizzly. Now a DNA test has confirmed that it is indeed a hybrid - possibly the first documented in the wild.

"We've known it's possible, but actually most of us never thought it would happen," said Ian Stirling, a polar bear biologist with the Canadian Wildlife Service in Edmonton. "
http://enews.earthlink.net/article/top?guid=20060511/4462b6c0_3ca6_15526200605112014489028

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Tamed 11,400 years ago, figs were likely first domesticated crop

Long before the grains, fig domestication may have marked a decisive shift in human history


CAMBRIDGE, Mass. -- Archaeobotanists have found evidence that the dawn of agriculture may have come with the domestication of fig trees in the Near East some 11,400 years ago, roughly a thousand years before such staples as wheat, barley, and legumes were domesticated in the region. The discovery dates domesticated figs to a period some 5,000 years earlier than previously thought, making the fruit trees the oldest known domesticated crop.

Ofer Bar-Yosef of Harvard University and Mordechai E. Kislev and Anat Hartmann of Bar-Ilan University report their findings in this week's issue of the journal Science.

"Eleven thousand years ago, there was a critical switch in the human mind -- from exploiting the earth as it is to actively changing the environment to suit our needs," says Bar-Yosef, professor of anthropology in Harvard's Faculty of Arts and Sciences and curator of Paleolithic archaeology at Harvard's Peabody Museum of Archaeology and Ethnology. "People decided to intervene in nature and supply their own food rather than relying on what was provided by the gods. This shift to a sedentary lifestyle grounded in the growing of wild crops such as barley and wheat marked a dramatic change from 2.5 million years of human history as mobile hunter-gatherers."

The researchers found nine small figs and 313 fig drupelets (a small part of an aggregate fruit such as a fig) at Gilgal I, a village in the Lower Jordan Valley, just 8 miles north of ancient Jericho, known to have been inhabited for some 200 years before being abandoned roughly 11,200 years ago. The carbonized figs were not distorted, suggesting that they may have been dried for human consumption. Similar fig drupelets were found at a second site located some 1.5 kilometers west of Gilgal.

The scientists compared the ancient figs to modern wild and domesticated variants and determined that they were a mutant selectively propagated by humans. In this variety of fig, known as parthenocarpic, the fruit develops without insect pollination and is prevented from falling off the tree, allowing it to become soft, sweet, and edible. However, because such figs do not produce seeds, they are a reproductive dead end unless humans interfere by planting shoots from the parthenocarpic trees.

"Once the parthenocarpic mutation occurred, humans must have recognized that the resulting fruits do not produce new trees, and fig tree cultivation became a common practice," Bar-Yosef says. "In this intentional act of planting a specific variant of fig tree, we can see the beginnings of agriculture. This edible fig would not have survived if not for human intervention."

Figs are very easily propagated: A piece of stem stuck in the ground will sprout roots and grow into a plant. No grafting or seeds are necessary. Bar-Yosef, Kislev, and Hartmann suggest that this ease of planting, along with improved taste resulting from minor mutations, may explain why figs were domesticated some five millennia before other fruit trees, such as the grape, olive, and date.

"The reported Gilgal figs, stored together with other vegetal staples such as wild barley, wild oat, and acorns, indicate that the subsistence strategy of these early Neolithic farmers was a mixed exploitation of wild plants and initial fig domestication," Bar-Yosef says. "Apparently, this kind of economy, a mixture of cultivation of wild plants, planting fig trees and gathering other plant foods in nature, was widely practiced during the second half of the 12th millennium before present throughout the Levant, the western wing of the Fertile Crescent."

###


Bar-Yosef, Kislev, and Hartmann's research was sponsored by the American School of Prehistoric Research at Harvard's Peabody Museum, the Israel Museum in Jerusalem, the Shelby-White-Leon Levi Foundation, and the Koschitzky Foundation at Bar-Ilan University.

SOURCE; EUREKA ALERT

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" Source: Max Planck Institute of Biochemistry

Posted: June 2, 2006

Semiconductor Brain: Nerve Tissue Interfaced With A Computer Chip

For the first time, scientists at the Max-Planck Institute for Biochemistry in Martinsried near Munich coupled living brain tissue to a chip equivalent to the chips that run computers. The researchers under Peter Fromherz have reported this news in the online edition of the Journal of Neurophysiology (May 10, 2006).

Before informational input perceived by the mammalian brain is stored in the long-term memory, it is temporarily memorised in the hippocampus*. Understanding the function of the hippocampus as an important player in the memory process is a major topic of current brain research. Thin slices of this brain region provide the appropriate material to study the intact neural network of the hippocampus.

Methods commonly used in neurophysiology are invasive, restricted to a small number of cells or suffer from low spatial resolution. The scientists in Martinsried developed a revolutionary non- invasive technique that enables them to record neural communication between thousands of nerve cells in the tissue of a brain slice with high spatial resolution. This technique involves culturing razor-thin slices of the hippocampus region on semiconductor chips. These chips were developed in collaboration with Infineon Technologies AG and excel in their density of sensory transistors: 16384 transistors on an area of one square millimeter record the neural activity in the brain.

Recording the activity patterns of the united cell structure of an intact mammalian brain tissue represents a significant technological breakthrough. Employing the new technique, the biophysicists working under the direction of Peter Fromherz were able to visualize the influence of pharmaceutical compounds on the neural network. This makes the “brain-chip” from Martinsried a novel test system for brain and drug research.

As early as 1991, Peter Fromherz and his co-workers succeeded in interfacing single leech nerve cells with semiconductor chips. Subsequent research gave rise to bidirectional communication between chip and small networks of a few molluscan nerve cells. In this project, it was possible to detect the signalling between cells via their synapses. The chips used in these studies were developed and produced by the scientists themselves. The production requirements of the chip described above made collaboration with industry indispensable. With the resulting novel hybrid system of neural tissue and semiconductor, the scientists take a great step forward towards neurochip prosthetics and neurocomputation.

Original publication: M. Hutzler, A. Lambacher, B. Eversmann, M. Jenkner, R. Thewes, and P. Fromherz: High- resolution multi-transistor array recording of electrical field potentials in cultured brain slices. Journal of Neuropyhsiology "

http://www.sciencedaily.com/releases/2006/06/060602172512.htm
« Last Edit: 05/06/2006 18:05:38 by ROBERT »
 

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