In Neutrino-Less Double-Beta Decay Search, Physicists Excel
|11:20:54 PM, Friday, July 20, 2012|
"(Phys.org, July 19, 2012) Physicists Andrea Pocar and Krishna Kumar of the University of Massachusetts Amherst, part of an international research team, recently reported results of an experiment conducted at the Enriched Xenon Observatory (EXO), located in a salt mine one-half mile under Carlsbad, New Mexico, part of a decades-long search for evidence of the elusive neutrino-less double-beta decay of Xenon-136.
Pocar, Kumar and the team of 60 scientists using an instrument called the EXO-200 detector, succeeded in setting a new lower limit for the half-life of this ephemeral nuclear decay. Though no one has yet seen it, important progress was made.
Pocar explains, "This result is particularly interesting because it very nearly excludes a 10-year old claim for observing such a decay in germanium-76. One of the physics community's goals for all this time has been to test that claim. We now have a detector that is able to probe half-lives which are 10^15 times the age of the universe. This alone is a remarkable achievement."
If observed someday, the existence of neutrinoless double-beta decay would require a new theoretical explanation of particle physics, he adds. Many theorists believe that it should exist. "A number of factors make this seem possible. It could tell us something about the asymmetry between matter and anti-matter that we observe in the universe," Pocar notes. Latest findings are reported in the current issue of Physical Review Letters..."
Parts of Mars Interior as Wet as Earth's
|2:07:08 AM, Friday, July 20, 2012|
"(Space.com, June 23, 2012) The interior of Mars holds vast reservoirs of water, with some spots apparently as wet as Earth's innards, scientists say.
The finding upends previous studies, which had estimated that the Red Planet's internal water stores were scanty at best — something of a surprise, given that liquid water apparently flowed on the Martian surface long ago.
"It’s been puzzling why previous estimates for the planet’s interior have been so dry," co-author Erik Hauri, of the Carnegie Institution of Washington, said in a statement. "This new research makes sense and suggests that volcanoes may have been the primary vehicle for getting water to the surface."
The scientists examined two Martian meteorites that formed in the planet's mantle, the layer under the crust. These rocks landed on Earth about 2.5 million years ago, after being blasted off the Red Planet by a violent impact.
Using a technique called secondary ion mass spectrometry, the team determined that the mantle from which the meteorites derived contained between 70 and 300 parts per million (ppm) of water. Earth's mantle, for comparison, holds roughly 50-300 ppm water, researchers said.
"The results suggest that water was incorporated during the formation of Mars and that the planet was able to store water in its interior during the planet’s differentiation," Hauri said..."
Slowest Greenland Sharks Hunts Sleeping Prey
|2:00:10 AM, Friday, July 20, 2012|
"(BBC 22 June 2012) Researchers have measured the swimming speed of the ocean's slowest shark.
Data-logging tags revealed that Greenland sharks "cruise" at 0.34m per second - less than 1mph.
The study showed that, even when the languid fish embarks on a burst of speed in order to hunt, it is far too slow to catch a swimming seal.
Since the species is known to eat seals, the scientists think it probably "sneaks up on them" as they sleep under the water.
The Greenland shark was already known to be the world's slowest swimming shark, but its sluggishness surprised the scientists.
Yuuki Watanabe from the National Institute of Polar Research in Tokyo, who took part in the study, said that, when you account for the size of its body, it is the slowest fish in the ocean.
Previous research had revealed seal remains in the stomachs of the sharks.
"It was hard to understand," he told BBC Nature, "because [it would seem] impossible for them to catch fast-swimming seals."
The researcher joined Dr Kit Kovacs and Dr Christian Lydersen from the Norwegian Polar Institute, to tag Greenland sharks in the waters off Svarlbard..."
New Planet Found: Molten 'Mars' Is 'Right Around the Corner'
|1:51:47 AM, Friday, July 20, 2012|
"(Nat. Geo. July 19, 2012) In a surprise find, astronomers have discovered a planet possibly covered with oceans of magma "right around the corner."
Even more exciting to scientists is its size: about the same as Mars's, which would make the new world the closest known planet smaller than Earth.
Researchers using NASA's Spitzer Space Telescope essentially stumbled upon the new planet while studying a hot, Neptune-size planet called GJ 436b.
In their data, however, the team caught a faint signal of the new planet and named it UCF-1.01, after their institution, the University of Central Florida. Both worlds were detected by watching for regular dimming of their host star, indicating a planet transiting, or crossing in front of, the star.
"We have a sub-Earth-sized planet that's slightly larger than Mars and essentially right around the corner, at least on a cosmic scale," said Kevin Stevenson, a planetary scientist now at the University of Chicago, who led the study that revealed UCF-1.01.
"It's one of the nearest transiting planets, it's tiny, and it may not be alone."
It's a Small World After All
Large planets are easier to find, but they're generally gas giants that don't have a rocky surface or an atmosphere like Earth's. So scientists are scanning the skies for smaller worlds, which should be more likely to support life as we know it..."
Physicists Review Progress in Understanding the 'Primordial Soup'
|1:42:52 AM, Friday, July 20, 2012|
"(Phys.org July 19, 2012) A review article appearing in the July 20, 2012, issue of the journal Science describes groundbreaking discoveries that have emerged from the Relativistic Heavy Ion Collider (RHIC) at the Brookhaven National Laboratory, synergies with the heavy-ion program at the Large Hadron Collider (LHC) in Europe, and the compelling questions that will drive this research forward on both sides of the Atlantic. With details that help enlighten our understanding of the hot nuclear matter that permeated the early universe, the article is a prelude to the latest findings scientists from both facilities will present at the next gathering of physicists dedicated to this research — Quark Matter 2012, August 12-18 in Washington, D.C.
“Nuclear matter in today’s universe hides inside atomic nuclei and neutron stars,” begin the authors, Barbara Jacak, a physics professor at Stony Brook University and spokesperson for the PHENIX experiment at RHIC, and Berndt Mueller, a theoretical physicist at Duke University. Collisions between heavy ions at machines like RHIC, running since 2000, and more recently, the LHC, make this hidden realm accessible by recreating the extreme conditions of the early universe on a microscopic scale. The temperatures achieved in these collisions — more than 4 trillion degrees Celsius, the hottest ever created in a laboratory — briefly liberate the subatomic quarks and gluons that make up protons and neutrons of ordinary atomic nuclei so scientists can study their properties and interactions.
“Quarks and the gluons that hold them together are the building blocks of all the visible matter that exists in the universe today — from stars, to planets, to people,” Jacak said. “Understanding the evolution of our universe thus requires knowledge of the structure and dynamics of these particles in their purest form, a primordial ‘soup’ known as quark-gluon plasma (QGP).”
RHIC was the first machine to demonstrate the formation of quark-gluon plasma, and determine its unexpected properties. Instead of an ideal gas of weakly interacting quarks and gluons, the QGP discovered at RHIC behaves like a nearly frictionless liquid. This matter’s extremely low viscosity (near the lowest theoretically possible), its ability to stop energetic particle jets in their tracks, and its very rapid attainment of such a high equilibrium temperature all suggest that the fluid’s constituents are quite strongly interacting, or coupled..."
'Impossible’ Binary Stars Discovered
|1:32:33 AM, Friday, July 20, 2012|
"(ScienceDaily July 5, 2012) A team of astronomers have used the United Kingdom Infrared Telescope (UKIRT) on Hawaii to discover four pairs of stars that orbit each other in less than 4 hours. Until now it was thought that such close-in binary stars could not exist. The new discoveries come from the telescope's Wide Field Camera (WFCAM) Transit Survey, and appear in the journal Monthly Notices of the Royal Astronomical Society.
About half of the stars in our Milky Way galaxy are, unlike our Sun, part of a binary system in which two stars orbit each other. Most likely, the stars in these systems were formed close together and have been in orbit around each other from birth onwards. It was always thought that if binary stars form too close to each other, they would quickly merge into one single, bigger star. This was in line with many observations taken over the last three decades showing the abundant population of stellar binaries, but none with orbital periods shorter than 5 hours.
For the first time, the team have investigated binaries of red dwarfs, stars up to ten times smaller and a thousand times less luminous than the Sun. Although they form the most common type of star in the Milky Way, red dwarfs do not show up in normal surveys because of their dimness in visible light.
For the last five years, UKIRT has been monitoring the brightness of hundreds of thousands of stars, including thousands of red dwarfs, in near-infrared light, using its state-of-the-art Wide-Field Camera (WFC). This study of cool stars in the time domain has been a focus of the European (FP7) Initial Training Network 'Rocky Planets Around Cool Stars' (RoPACS) which studies planets and cool stars..."
NASA's Mars Rover Two Weeks from Landing
|2:46:07 AM, Thursday, July 19, 2012|
"(Phys.org July 17) - NASA's most advanced planetary rover is on a precise course for an early August landing beside a Martian mountain to begin two years of unprecedented scientific detective work. However, getting the Curiosity rover to the surface of Mars will not be easy.
"The Curiosity landing is the hardest NASA mission ever attempted in the history of robotic planetary exploration," said John Grunsfeld, associate administrator for NASA's Science Mission Directorate, at NASA Headquarters in Washington. "While the challenge is great, the team's skill and determination give me high confidence in a successful landing."
The Mars Science Laboratory mission is a precursor for future human missions to Mars. President Obama has set a challenge to reach the Red Planet in the 2030s.
To achieve the precision needed for landing safely inside Gale Crater, the spacecraft will fly like a wing in the upper atmosphere instead of dropping like a rock. To land the 1-ton rover, an airbag method used on previous Mars rovers will not work. Mission engineers at NASA's Jet Propulsion Laboratory in Pasadena, Calif., designed a "sky crane" method for the final several seconds of the flight. A backpack with retro-rockets controlling descent speed will lower the rover on three nylon cords just before touchdown..."
Neanderthals Had Knowledge of Plants' Healing Qualities: Study
|2:24:10 AM, Thursday, July 19, 2012|
"(phys.org July 18, 2012) An international team of researchers, led by the Universitat Autònoma de Barcelona and the University of York, has provided the first molecular evidence that Neanderthals not only ate a range of cooked plant foods, but also understood its nutritional and medicinal qualities.
Until recently Neanderthals, who disappeared between 30,000 and 24,000 years ago, were thought to be predominantly meat-eaters. However, evidence of dietary breadth is growing as more sophisticated analyses are undertaken.
Researchers from Spain, the UK and Australia combined pyrolysis gas-chromatography-mass spectrometry with morphological analysis of plant microfossils to identify material trapped in dental calculus (calcified dental plaque) from five Neanderthals from the north Spanish site of El Sidrón.
Their results, published in Naturwissenschaften – The Science of Nature this week, provide another twist to the story - the first molecular evidence for medicinal plants being used by a Neanderthal individual.
The researchers say the starch granules and carbohydrate markers in the samples, plus evidence for plant compounds such as azulenes and coumarins, as well as possible evidence for nuts, grasses and even green vegetables, argue for a broader use of ingested plants than is often suggested by stable isotope analysis..."
How the Same Plant Species Can Programme Itself to Flower at Different Times in Different Climates
|1:13:54 AM, Tuesday, July 17, 2012|
"(Phys.org July 16, 2012) Researchers led by Professor Caroline Dean have uncovered the genetic basis for variations in the vernalization response shown by plants growing in very different climates, linking epigenetic mechanisms with evolutionary change.
Vernalization is a period of prolonged cold that some plants require before they will flower. This ensures that they only produce flowers after the damaging cold of winter has passed. The plant must have a way of ‘remembering’ how much cold weather it has endured and in 2011 the researchers uncovered the mechanism plants use. When sufficient time in the cold has passed, an epigenetic switch silences a flowering-repressor gene called FLC. These epigenetic changes are then passed on to daughter cells during the rest of the plants developmental cycle.
Different plants have different vernalization requirements, as the length of winter cold they experience varies with geography and climate. In new research published in the journal Science, Professor Dean’s team have worked out how different plants set the level at which this epigenetic switch is triggered. They looked at a variety of Arabidopsis thaliana derived from North Sweden (Lov-1), and compared it to the reference ‘Columbia’ variety. Columbia needs 4 weeks of cold to trigger the epigenetic switch. The Lov-1 variety needs 9 weeks of cold to achieve the same, a natural variation to cope with the longer winters at northern latitudes..."
Lab-Engineered Muscle Implants Restore Function in Animals
|11:18:55 PM, Monday, July 16, 2012|
"(ScienceDaily July 16, 2012) - New research shows that exercise is a key step in building a muscle-like implant in the lab with the potential to repair muscle damage from injury or disease. In mice, these implants successfully prompt the regeneration and repair of damaged or lost muscle tissue, resulting in significant functional improvement.
"While the body has a capacity to repair small defects in skeletal muscle, the only option for larger defects is to surgically move muscle from one part of the body to another. This is like robbing Peter to pay Paul," said George Christ, Ph.D., a professor at Wake Forest Baptist Medical Center's Institute for Regenerative Medicine. "Rather than moving existing muscle, our aim is to help the body grow new muscle."
In the current issue of Tissue Engineering Part A, Christ and team build on their prior work and report their second round of experiments showing that placing cells derived from muscle tissue on a strip of biocompatible material -- and then "exercising" the strip in the lab -- results in a muscle-like implant that can prompt muscle regeneration and significant functional recovery. The researchers hope the treatment can one day help patients with muscle defects ranging from cleft lip and palate to those caused by traumatic injuries or surgery.
For the study, small samples of muscle tissue from rats and mice were processed to extract cells, which were then multiplied in the lab. The cells, at a rate of 1 million per square centimeter, were placed onto strips of a natural biological material. The material, derived from pig bladder with all cells removed, is known to be compatible with the body..."
As Old as Clovis Sites, but Not Clovis: Paisley Caves, Oregon Yields Western Stemmed Points, More Human DNA
|1:54:24 AM, Monday, July 16, 2012|
"(ScienceDaily July 12, 2012) - Archaeological work in Oregon's Paisley Caves has found evidence that Western Stemmed projectile points -- darts or thrusting spearheads -- were present at least 13,200 calendar years ago during or before the Clovis culture in western North America.
In a paper in the July 13 issue of Science, researchers from 13 institutions lay out their findings, which also include substantial new documentation, including "blind-test analysis" by independent labs, that confirms the human DNA pulled earlier from human coprolites (dried feces) and reported in Science (May 9, 2008) dates to the same time period.
The new conclusions are based on 190 radiocarbon dates of artifacts, coprolites, bones and sagebrush twigs meticulously removed from well-stratified layers of silt in the ancient caves. Absent from the Paisley Caves, said the project's lead researcher Dennis L. Jenkins of the University of Oregon's Museum of Natural and Cultural History, is diagnostic evidence of the Clovis culture such as the broad, concave-based, fluted Clovis projectile points.
The radiocarbon dating of the Western Stemmed projectiles to potentially pre-Clovis times, Jenkins said, provides new information in the decades-old debate that the two point-production technologies overlapped in time and may have developed separately. It suggests that Clovis may have arisen in the Southeastern United States and moved west, while the Western Stemmed tradition began, perhaps earlier, in the West and moved east..."
Researchers Create Highly Conductive and Elastic Conductors Using Silver Nanowires
|1:07:53 AM, Monday, July 16, 2012|
"(phys.org July 12, 2012) Researchers from North Carolina State University have developed highly conductive and elastic conductors made from silver nanoscale wires (nanowires). These elastic conductors could be used to develop stretchable electronic devices.
Stretchable circuitry would be able to do many things that its rigid counterpart cannot. For example, an electronic "skin" could help robots pick up delicate objects without breaking them, and stretchable displays and antennas could make cell phones and other electronic devices stretch and compress without affecting their performance. However, the first step toward making such applications possible is to produce conductors that are elastic and able to effectively and reliably transmit electric signals regardless of whether they are deformed.
Dr. Yong Zhu, an assistant professor of mechanical and aerospace engineering at NC State, and Feng Xu, a Ph.D. student in Zhu's lab have developed such elastic conductors using silver nanowires.
Silver has very high electric conductivity, meaning that it can transfer electricity efficiently. And the new technique developed at NC State embeds highly conductive silver nanowires in a polymer that can withstand significant stretching without adversely affecting the material's conductivity. This makes it attractive as a component for use in stretchable electronic devices..."
Early Human Ancestor, Australopithecus Sediba, Fossils Discovered in Rock
|10:57:23 PM, Saturday, July 14, 2012|
"(ScienceDaily July 12, 2012) - Scientists from the Wits Institute for Human Evolution based at the University of the Witwatersrand in Johannesburg have just announced the discovery of a large rock containing significant parts of a skeleton of an early human ancestor. The skeleton is believed to be the remains of 'Karabo', the type skeleton of Australopithecus sediba, discovered at the Malapa Site in the Cradle of Humankind in 2009.
Professor Lee Berger, a Reader in Palaeoanthropology and the Public Understanding of Science at the Wits Institute for Human Evolution, will make the announcement at the Shanghai Science and Technology Museum in Shanghai, China on 13 July 2012.
"We have discovered parts of a jaw and critical aspects of the body including what appear to be a complete femur (thigh bone), ribs, vertebrae and other important limb elements, some never before seen in such completeness in the human fossil record," says Berger. "This discovery will almost certainly make Karabo the most complete early human ancestor skeleton ever discovered. We are obviously quite excited as it appears that we now have some of the most critical and complete remains of the skeleton, albeit encased in solid rock. It's a big day for us as a team and for our field as a whole...""
Skinny Searchers Keep Fat Ants Full
|10:27:45 PM, Saturday, July 14, 2012|
"(sciencenews.org July 12th, 2012) Using tiny key cards glued to ants’ backs, researchers have figured out how colonies manage their food stores: A body weight–based strategy determines who’s doing the hunting and when.
To test the relevance of body weight and experience in foraging, researchers saddled ants (Temnothorax albipennis) with electronic tags smaller than a pinhead and installed a mini automatic door in the colony’s nest to control who could leave.
“It’s like if you didn’t want your teenage son to drive the car, you could disable his garage-door opener so he couldn’t get out,” says biologist Elva Robinson of the University of York in England.
Blocking lean ants from leaving forced stay-at-home tubby ants to gain experience foraging. But the insects switched back to their normal jobs when researchers reopened the doors, Robinson and colleagues report online July 12 in the Journal of Experimental Biology..."
Lost Viking Military Town Unearthed in Germany?
|10:15:46 PM, Saturday, July 14, 2012|
"(Nat. Geo. July 11, 2012) A battle-scarred, eighth-century town unearthed in northern Germany may be the earliest Viking settlement in the historical record, archaeologists announced recently.
Ongoing excavations at Füsing (map), near the Danish border, link the site to the "lost" Viking town of Sliasthorp—first recorded in A.D. 804 by royal scribes of the powerful Frankish ruler Charlemagne.
Used as a military base by the earliest Scandinavian kings, Sliasthorp's location was unknown until now, said dig leader Andres Dobat, of Aarhus University in Denmark.
Whether it proves to be the historic town or not, the site offers valuable insights into military organization and town planning in the early Viking era, according to the study team.
Some 30 buildings have been uncovered since excavations began in 2010. Aerial photographs and geomagnetic surveys indicate about 200 buildings in total..."
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