Oct 5, 2012

Mass of Dark Matter Revealed by Precise Measurements of the Galaxy

A research team, led by Associate Professor Mareki Honma from the National Astronomical Observatory of Japan (NAOJ), has succeeded in precisely determining the astronomical yardstick for the Galaxy based upon the precise distance measurements with VERA from NAOJ and other advanced radio telescopes. The new findings are that the distance from the sun to the Galactic center is 26,100 light-years, and that the Galactic rotation velocity in the solar system is 240km/s.

The Galactic rotation velocity from this research is higher than that of previously known (220km/s). This results in the conclusion that the mass of the Galaxy, especially that of dark matter, is about 20% larger than what has been previously considered.

A research team, led by Associate Professor Mareki Honma(NAOJ) has reached the following two conclusions:

(1) The distance from the solar system to the galactic center is approximately 26,100 light years (*1);

(2) The galactic rotation velocity in the solar system (V0) (*2) is approximately 240km/s.

These conclusions are drawn based upon the precise distances to celestial objects in the Galaxy and their proper motions, a technical term to describe the stars' change in position. The International Astronomical Union has endorsed V0=220km/s; this value was announced in 1986. When the V0 value derived from this research is applied, the mass of dark matter in the galaxy is about 20% larger than what has been considered so far.

VERA (VLBI Exploration of Radio Astrometry) (*3) and other VLBI arrays in the world were utilized to get most of the precise distances to about 50 objects and the data on their proper motions. At VERA, triangulation (*4) was used to precisely measure the distances to the objects and their proper motions. The research team plans to further increase the number for objects of which they measure the precise distances and proper motions. In addition, the team has hopes to deepen understanding of the Galaxy in which we all live by creating a 3D Galaxy map, and then determine motions and mass distribution in the Galaxy based upon the 3D map.

*1: A light year is a unit of distance, which is how far light can travel in one year at the speed of 300,000km/sec. It is equal to approximately 9.5 trillion km.

*2: The Galactic disk rotates around the Galactic center. It has been found that the rotation speed is almost constant, no matter whether it is near the center or near the outer edge.

*3: VERA stands for VLBI Exploration of Radio Astrometry while VLBI means Very Long Baseline Interferometry. This is a project to precisely measure distances to celestial objects with the principles of triangulation (see *4), and to identify the 3D structure of the Galaxy. Construction work was completed in 2002, and astronomical observations to measure distances to objects have been done on a regular basis since 2007. The 20-meter radio telescopes used for VERA are located at the following four places: Oshu City in Iwate Prefecture, Satsumasendai City in Kagoshima Prefecture, Ogasawara Village in Tokyo, and Ishigaki City in Okinawa Prefecture.

*4: Triangulation is a method to observe an object from two fixed spots and determine a distance from the difference of the apparent direction. It is used as the most reliable method to determine distances to stars located outside the solar system.

The difference of direction as seen from two different places is called parallax, or trigonometric parallax. When the distance from two points is equal, the trigonometric parallax is in inverse proportion to the distance to the star. They took advantage of the fact that Earth revolves around the sun once over a year in order to measure the distance to the stars. That means, for example, that the direction from Earth in summer is different from the one in winter by approximately one thirty-millionth degree when observing a star in the Galactic center. Even though the star is located in the Galaxy, the direction difference should be precisely measured because of the long distance to the star. The VERA project makes full use of the cutting-edge technologies of astronomical observation, so star location is measured with the super high accuracy of within one 360-millionth degree.

What is Our Milky Way Galaxy Like as a Galaxy?

What is our Milky Way Galaxy like? -- How big? How heavy? What shape? We know now that the Galaxy is a spiral galaxy, but precise information including its size, shape, and rotation velocity, has not been made clear yet.

The biggest reason is that we cannot see the Galaxy from the outside since we stay inside the Galaxy. In order to see the whole shape of the Galaxy from the inside, it is necessary to precisely measure the distance of each one of the many Galactic objects, and make a "Galactic map" with an overhead view.

In that case, trigonometric parallax, or annual parallax, is utilized to measure the distance to an object without any "what if?" assumptions. The trigonometric parallax is the difference in position of an object, which is generated when Earth orbits around the sun. However, the difference is extremely small; even that of Alpha Centauri, the nearest star from the Sun, is one arcsecond or less. Therefore, we could not measure any areas beyond 1,000 light-years away from the solar system by using the annual parallax because of the measurable limit of the parallax. The distance of 1,000 light-years is far smaller than the distance from the Sun to the Galactic center (approximately 26,100 light-years, as mentioned later). This means that measuring the area of the Galaxy has been a frontier left for modern astronomy.

Precise Triangulation by Radio Interferometers

VERA (VLBI Exploration of Radio Astrometry), with which we have continued our research, is a group of radio interferometers; 20-meter radio telescopes are installed in Oshu City in Iwate Prefecture, Satsumasendai City in Kagoshima Prefecture, Ogasawara Village in Tokyo, and Ishigaki City in Okinawa Prefecture. This is a project to precisely measure distances to objects with the technology of Very Long Baseline Interferometry (VLBI), and to identify the 3D structure of the Galaxy. Mizusawa VLBI Observatory of NAOJ is operating VERA in cooperation with Kagoshima University and other organizations. The construction of VERA was finished in 2002, and astronomical observations to measure distances to stars have been regularly conducted since 2007.

VERA has completed observations of more than 100 radio objects (maser sources) in the Galaxy, and so far we have reported on the precise distances and motions of approximately 30 of those objects. This time, we determined the Galactic yardstick based upon the precise distance measurements with the observation results of 52 objects in total (Figures 3 and 4): 19 star-forming regions (newly-born stars) observed at VERA, and other objects observed by the Very Long Baseline Array (VLBA) of US equipment, and by the European VLBI Network (EVN). In this report, the latest measurement results of VERA were added, making it the world's first analysis of Galactic structure using more than 50 objects.

Galactic Yardsticks Precisely Determined

This research successfully managed to determine the Galactic yardsticks precisely: the R0 value of the distance to the Galactic center from the solar system, and theΘ0 value of the Galactic rotation velocity in the solar system. The distance to the Galactic center is R0=8.0 +/- 0.5 kpc (approximately 26,100 light-years +/-1,600 light-years), and the Galactic rotation velocity in the solar system isΘ0=240 +/- 14 km/s.

The value of Galactic rotation velocity from this research is larger than V0=220km/s, the one endorsed by the International Astronomical Union (IAU) since 1986. This finding now forces them to change the rotation speed and mass distribution of the Galaxy, as mentioned later.

On the other hand, the distance to the galactic center is almost equal, within an 8.5 kpc (approximately 27,700 light-years) margin of error, as that endorsed by the IAU since 1986. However, one of the most important points is that this measurement was directly and more precisely done with the triangulation method and is more precise. In addition to these yardsticks, it is also confirmed that the Galactic rotation velocity is almost constant between the distances of 10,000 and 50,000 light-years from the Galactic center.

Read more at Science Daily

Dish-Grown Sperm and Eggs Produce Mouse Pups

Want baby mice? Grab a petri dish. After producing normal mouse pups last year using sperm derived from stem cells, a Kyoto University team of researchers has now accomplished the same feat using eggs created the same way. The study may eventually lead to new ways of helping infertile couples conceive.

“This is a significant achievement that I believe will have a sustained and long-lasting impact on the field of reproductive cell biology and genetics,” says Amander Clark, a stem cell biologist at University of California, Los Angeles.

The stem cells in both cases are embryonic stem (ES) cells and induced pluripotent stem (iPS) cells. The former are taken from embryos and the latter are adult tissue cells that are reprogrammed to act like stem cells. In theory, both can produce all of the body’s cell types, yet most researchers have been unable to turn them into germ cells, precursors of sperm and eggs.

The Kyoto group, led by stem cell biologist Mitinori Saitou, found a process that works. As with the sperm, the group started with ES and iPS cells and cultured them in a cocktail of proteins to produce primordial germ cell-like cells. To get oocytes, or precursor egg cells, they then mixed the primordial cells with fetal ovarian cells, forming reconstituted ovaries that they then grafted onto natural ovaries in living mice. Four weeks and 4 days later, the primordial germ cell-like cells had developed into oocytes. The team removed the ovaries, harvested the oocytes, fertilized them in vitro, and implanted the resulting embryos into surrogate mothers. About 3 weeks later, normal mouse pups were born, the researchers report online today in Science.

“It is remarkable that one can produce oocytes capable of sustaining complete development starting with embryonic stem cells,” says Davor Solter, a developmental biologist at Singapore’s Institute of Medical Biology. Clark adds that the immediate impact of the work will be on understanding the molecular mechanisms involved in forming germ cells. Saitou says that with a bit more progress in understanding the complex interactions at work, they may be able to coax the cells through the entire oocyte development process in a lab dish. If successful, “we may be able to skip the grafting,” he says.

Read more at Wired Science

Einstein's Letter Questioning God Goes Up for Auction

From studying slices of his brilliant brain to probing profound physics theories, scientists and enthusiasts alike have long been spellbound by Albert Einstein. Now, an auction is offering the world a peek at Einstein's thoughts on what may be humanity's most profound question: the existence of God.

The private letter written by Einstein expressing his views on God and religion will go up for auction Monday (Oct. 8) on eBay. In the letter, he calls belief in religion and God "pretty childish" and ridicules the idea that the Jews are a chosen people.

"This is the most historic and significant piece we have listed on eBay," Eric Gazin, president of Auction Cause, the agency managing the sale, told LiveScience in an email. "We are excited to offer a person or organization an opportunity to own perhaps one of the most intriguing 20th-century documents in existence. This personal letter from Einstein represents the nexus of science, theology, reason and culture."

Einstein handwrote the letter in German to Jewish philosopher Eric B. Gutkind on Jan. 3, 1954, a year before Einstein's death. The letter was a response to Gutkind's book "Choose Life: The Biblical Call to Revolt" (1952, H. Schuman; 1st edition).

In part of his letter, Einstein writes, "For me the Jewish religion like all other religions is an incarnation of the most childish superstitions. And the Jewish people to whom I gladly belong and with whose mentality I have a deep affinity have no different quality for me than all other people. As far as my experience goes, they are also no better than other human groups, although they are protected from the worst cancers by a lack of power. Otherwise I cannot see anything 'chosen' about them," as translated from German by Joan Stambaugh.

In his book, Gutkind suggested that unlike the mass hypnosis spoiling mankind at the time, "The soul of the Jewish people was never a mass-soul. Israel's soul could not be hypnotized; it never succumbed to hypnotic assaults. … The soul of Israel is incorruptible."

And as for whether Einstein believed in God? Yes and no, it seems.

In a March 24, 1954 letter, he is quoted as writing, "It was, of course, a lie what you read about my religious convictions, a lie which is being systematically repeated. I do not believe in a personal God and I have never denied this but have expressed it clearly. If something is in me which can be called religious then it is the unbounded admiration for the structure of the world so far as our science can reveal it."

However, in the letter to Gutkind, Einstein wrote the word God was "nothing more than the expression and product of human weaknesses, the Bible a collection of honorable, but still primitive legends which are nevertheless pretty childish."

This isn't the first time this "God" letter has been up for auction: In 2008, an unidentified buyer who had "a passion for theoretical physics" bought the letter at a Bloomsbury Auctions sale in London for $404,000, 25 times its presale estimate, according to an article in the New York Times.

The letter to Gutkind has been stored in a temperature-, humidity- and light-controlled environment at an academic institution specializing in the care of cultural heritage collections, according to an eBay description. Since the letter has been known among scientists for more than 50 years, the description reads, its authenticity has never been questioned. The letter is in its original envelope, holding a stamp and postmark from Princeton, N.J, where Einstein lived toward the end of his life.

The last few years have seen an outpouring of projects that bring the famous genius down to earth: For instance, in March, a large collection of Einstein's documents — everything from personal letters to scientific manuscripts -- went online as part of an endeavor by the Albert Einstein Archives at the Hebrew University of Jerusalem and at the Einstein Papers Project at the California Institute of Technology. The archive reveals both the academic side of Einstein — with one of only three existing manuscripts containing the famous E=mc^2 equation written in Einstein's handwriting -- and his personal life -- with a postcard to his mother Pauline.

Read more at Discovery News

Russian Boy Finds Wooly Mammoth

An 11-year-old boy from Russia's north has stumbled upon a well-preserved wooly mammoth, in what scientists describe as the best such discovery since 1901.

Yevgeny Salinder, whose family lives near a polar station in the northern Taimyr Peninsula, discovered the frozen animal when he was strolling along the banks of the Yenisei River in late August.

"He sensed an unpleasant odor and saw something sticking out of the ground -- it was the mammoth's heels," said Alexei Tikhonov, director of the Saint Petersburg-based Zoological Museum, who rushed to the tundra after the boy's family had notified scientists of the historic find.

Tikhonov said the mammoth had died aged 15-16 around 30,000 years ago, adding his tusk, skin, an eye and an ear were clearly visible.

"His one-meter-long penis is also intact so we can conclude that this was a male," Tikhonov said.

Read more at Discovery News

Oct 4, 2012

Vitamins C and D (Still) Don't Prevent Colds

As we head into cold and flu season, many people swear by megadoses of vitamins C and D to stave off sickness. However there's more and more evidence that they won't do much good.

According to a BBC News story, "Scientists say they can find no convincing evidence to show that taking vitamin D supplements will fend off a cold. A New Zealand team did the 'gold standard' of tests -- a randomized placebo-controlled trial -- to see what impact the supplements would have. The 161 people who took daily vitamin D for 18 months caught as many colds as the 161 who took fake pills."

The new study, "Effect of Vitamin D3 Supplementation on Upper Respiratory Tract Infections in Healthy Adults," was conducted at the University of Auckland, New Zealand, and concluded, "In this trial, monthly administration of 100,000 IU of vitamin D did not reduce the incidence or severity of URTIs (upper respiratory tract infections) in healthy adults."

The study was reported in the Journal of the American Medical Association.

It's not just vitamin D that's worthless in preventing colds, it's also the old standby vitamin C. The idea of vitamin C as a panacea got a huge boost in the 1970s from Nobel Prize winning chemist Linus Pauling, who took three grams of vitamin C daily to prevent colds, and later claimed that the vitamin could treat a variety of diseases including cancer.

Though the claims were proven false, the basic idea that extra vitamin C will prevent colds remains. Though it won't help, it usually won't harm: unless a person is taking megadoses, excess vitamin C will simply be flushed out of the body. While certain people with vitamin deficiencies require supplements, most adults who eat a reasonably balanced diet get enough vitamins in their meals, and don’t require supplements.

One Australian study in 2004 reviewed dozens of clinical trials examining vitamin C's effect on colds. It found no significant difference in incidence of colds between people who took the vitamin every day and those who did not.

Read more at Discovery News

Tomb of Mayan Queen Found

Archaeologists in Guatemala say they have discovered the 7th-century tomb of Lady K'abel, one of the greatest queens of classic Maya civilization.

Unearthed during excavations of the royal Maya city of El Perú-Waka' in northwestern Petén, Guatemala, the grave contained the skeletal remains of a mature individual buried with rich offerings such as dozens of ceramic vessels, numerous carved jade, shell artifacts and a small, carved alabaster jar.

According to the archaeologists, the white vessel strongly suggest the tomb belonged to the warrior Queen Lady K'abel.

Carved as a conch shell, with a head and arm of an aged woman emerging from the opening, the alabaster jar portrayed a woman, mature with a lined face and a strand of hair in front of her ear, while on the other side it featured a brief glyphic text consisting of four hieroglyphs.

The final two glyphs named the owner as "Lady Waterlily-Hand, Princess of Calakmul."

"This is almost certainly an alternative spelling of the name of Lady K'abel, as both names consist of hands holding waterlilies and both are titled as princesses of Calakmul," David Freidel, professor of archaeology at Washington University in St. Louis and co-director of the expedition, said.

The most powerful person in Waka' during her lifetime, Lady K'abel is known in Maya archaeology because of a beautiful and detailed portrait of her in a stela dated to 692 A.D. The carved stone slab was looted from Waka' in the 1960s and is now in the Cleveland Art Museum.

Lady K'abel ruled with her husband, K'inich Bahlam, for at least 20 years (672-692 A.D.). She was the military governor of the Wak kingdom for her family, the imperial house of the Snake King, and carried the title Kaloomte', which translates to "Supreme Warrior."

"The significance of this woman's powerful role as a 'Kaloomte,' a title rarely associated with Maya women, provides tremendous insight on the nexus of gender and power in Classic Maya politics," Olivia Navarro-Farr, assistant professor of sociology and anthropology at The College of Wooster and co-director of the expedition, said.

The discovery of the tomb of the seventh-century Maya queen occurred while Navarro-Farr investigated "ritually potent" features at El Perú-Waka’, such as shrines, altars, and dedicatory offerings.

The tomb was found underneath various phases of a masonry shrine that had been placed on a staircase.

The shrine contained a monumental fire altar which had been dedicated by the sacrifice of a mature woman buried underneath it.

"Below that last shrine was a buried earlier version and it was below this earlier shrine that the royal tomb was found," Freidel and Navarro-Farr said.

It soon became clear to the archaeologists why the structure received so much ritual attention throughout its final occupation.

 "The golden age of the city, and the great queen and her husband who presided over it, were remembered and celebrated by ordinary people with their humble offerings," the researchers said.

Inside the tomb the team led by Freidel and Navarro-Farr found the skeletal remains of an individual, whose skull was almost covered by ceramic vessels.

Deterioration of the bones did not permit a clear identification of the subject as male or female.

"If female, the interred individual had more robust than gracile features," the researchers said. The traits would match the queen's portrait on the stela on display at the Cleveland Art Museum.

Read more at Discovery News

Vegetarian Dinosaurs Were Champion Chompers

Giant plant-eating dinosaurs may have been champion chewers up there with the likes of mammals such as horses, bison or elephants, researchers say.

The finding could help explain why these behemoths dominated the plains of Europe, Asia and North America during the last part of the age of dinosaurs, scientists added.

Duck-billed herbivores called hadrosaurids thundered across the world during the Late Cretaceous period, dating about 65 million to 100 million years ago. They grazed on horsetails, ferns and primitive flowering plantson the ground, and browsed on Earth's conifers.

The plants these dinosaurs fed on were tough and covered with hard, tooth-gouging particles. Hadrosaurids chewed their meals with teeth that possessed flattened grinding surfaces much like those of horses and bison. Some hadrosaurids sported up to 1,400 of these teeth, and were continually replacing them.

"They were like walking pulp mills -- I suspect they could eat any kind of plant they ran into," said researcher Gregory Erickson, a paleobiologist at Florida State University in Tallahassee.

The chewing teeth of mammals can be relatively complex, possessing four major types of tissue of varying hardness. These combinations help keep the grinding ridges and valleys on a tooth's surface from wearing and breaking down. In contrast, most reptile teeth are comparably simple, with only two kinds of tissue -- hard enamel and a softer bone-like material.

"It didn't make sense to me that the complex surfaces we see in hadrosaur teeth could be done with the simple tooth tissues reptiles are supposed to have," Erickson said.

Now researchers find hadrosaurid teeth were far more complex than those of known reptiles — they were composed of six different types of tissue.

"They were as sophisticated, if not more sophisticated, than any known mammal," Erickson told LiveScience.

After analyzing fossil hadrosaurid teeth with microscopy and X-rays and by testing them with diamond-tipped probes, the researchers found the way tissues were distributed varied substantially within each tooth. This would allow a single tooth to assume different forms and functions as the tooth changed over time, exposing different surfaces as the teeth migrated across the chewing surfaces in the mouths of the dinosaurs over time.

Read more at Discovery News

Star Swoops in Close to Milky Way's Black Hole

Astronomers have found a star that breaks speed records as it orbits the Milky Way's central black hole, covering 3,100 miles (5,000 kilometers) per second as it whips around the black hole in less than a dozen years.

The discovery offers scientists a unique chance within the decade to test Einstein's theory of relativity in an extreme environment.

The star is named S0-102. It's one of a class of "S-stars" that surround the center of the sun's home galaxy in a kind of spherical shell. It has an orbital period of 11.5 years, give or take 3 1/2 months, making it the shortest-period star ever found in the region. The previous record was set by S0-2, which has a 16-year period.

The presence of two short-period stars means astronomers can look at the precession (change in orientation) of their orbits over time and use that information to learn how much space has been curved by the immense gravity of the galaxy's central black hole, which weighs in at 4 million times the sun's mass.

Such tests have been done before. The most famous study looked at the movement of the planet Mercury around the sun. Astronomers of the 19th century noticed Mercury's orbit was precessing more than could be accounted for by Newton's theory of gravity. At first they proposed the presence of another planet inside Mercury's orbit, but in the early 20th century Einstein was able to use his theory of relativity to predict exactly how much "extra" precession should happen as a result of space being curved by the sun's gravity, forcing the planet into a different path.

Other similar observations have been made of pairs of dense objects called neutron stars. However, because these stars can be only up to three times as massive as the sun, they don't curve space-time much more than the warping scientists see in the solar neighborhood.

Thus, studying the space-time around the Milky Way's gigantic black hole should offer an unprecedented test.

"This is the same idea in an unexplored parameter space," said Andrea Ghez, a professor of astronomy at the University of California, Los Angeles, and one of the leaders of the research team that found S0-102. "We know relativity breaks down on a small scale. We want to get as close to the event horizon as possible."

The event horizon around a black hole is the point of no return -- the closest anything can come without falling in.

The stars S0-102 and S0-2 appear to get fairly close. Their orbits are so near the central black hole that the effects of space-time curvature should be clearly visible. And the presence of these two short-period stars will allow observers to measure the local space-time curvature far more accurately than one star would.

The duo also helps astronomers take into account the fact that the gravitational mass of the central black hole isn't a perfect point; there are lots of other objects, such as remnants of dead stars, in the region that can cloud the observations.

"Close" though, is a relative term. A 4 million solar-mass black hole has a radius of about 6.8 million miles (11 million kilometers). The closest S0-102 gets is 260 times the distance between the Earth and the sun, or about five times the distance between the sun and Pluto at its farthest.

One of the unique things about S0-102 is astronomers have observed its orbit through one complete circuit. It last made its closest approach (periapse) to the central black hole in 2009, and should make another in 2020. Meanwhile, S0-2, the other record-holder, will reach periapse in 2018 or 2019. That's when it will be possible to measure their orbital precessions.

Another test of relativity will be the stars' gravitational red shift. Light traveling from a star in a region of very curved space-time should be shifted from what one might expect in normal space. With two stars to observe, both of them reaching periapse in the next 10 years, researchers hope to get an accurate measurement.

S0-102 was found by the Keck Observatory in Hawaii. Using adaptive optics, which correct for the blurriness caused by the Earth's atmosphere, the telescope made observations in long-wavelength infrared light that allowed the detection of S0-102 and other nearby stars. But to make some of the measurements to test relativity, scientists will need a new generation of instruments, including the huge Thirty Meter Telescope under construction in Hawaii.

Read more at Discovery News

Oct 3, 2012

Fanged, Tiny Veggie Dinosaur Found

A "punk-sized" dinosaur with porcupine-like bristles featured some flashy stabbing self-sharpening fangs -- although it likely only had a taste for plants.

The newly identified dinosaur, named Pegomastax africanus, or "thick jaw from Africa," was a mere two feet long and weighed less than a modern housecat in the flesh. Its remains were chipped out of 200-million-year-old red rock from South Africa.

Though small, the dinosaur was a plucky survivor.

"I think the bristles would have made it look at least a little bigger than it was -- perhaps they could poke out more strongly when excited," Paul Sereno, author of a study about the find in the journal ZooKeys, told Discovery News.

"The main defense would be speed of escape," added Sereno, a paleontologist and professor at the University of Chicago. "These were very long-legged fast critters. (They could inflict) a nipping bite if cornered, using the fangs much like a peccary or fanged deer."

Sereno studied the remains, which belong to a single specimen uncovered in a collection of fossils at Harvard University. Sereno has identified it as a heterodontosaur. This group of herbivores included some of the first dinosaurs to spread across the planet.

At the time, the supercontinent Pangea had just begun to split into northern and southern landmasses. This led to heterodontosaurs divided into northern species with simple triangular teeth, and southern species, like Pegomastax, with taller tooth crowns.

Pegomastax had 1-inch-long jaws that supported a short, parrot-shaped beak up front, a pair of stabbing canine teeth, and tall teeth tucked behind. The teeth in the upper and lower jaws operated like self-sharpening scissors, with shearing wear facets that slid past one another when the jaw was closed.

Sereno believes the less than 3-inch-long skull was probably adapted to plucking fruit, and not to ripping flesh out of animal prey. This is supported by the way the teeth met during a bite, their shape, and wear pattern.

Given that the wear facets in this and related dinosaurs are "blunt with broken shards…this would not be good for a meat eater and suggests the teeth were more for digging or rooting around and in nipping competitions or occasional defense than in acting like steak knives necessary for feeding on a daily basis."

With its bristles, Pegomastax looked something like a "nimble two-legged porcupine," according to Sereno. Similar bristles first came to light in another comparable sized heterodontosaur called Tianyulong from China. The bristles spread across its body from the neck to the tip of its tail.

As for the term "punk," Sereno explained that he prefers that description over the word "dwarf," since "dinosaurs started out small (and) we tend to forget that."

He added, "These plant-eaters are among the very oldest we know from the bird-hipped side of the dinosaur tree. They started out small, and some of them got a bit smaller to be among the smallest dinosaurs we know."

While it's unknown what carnivores might have feasted on Pegomastax, this tiny dinosaur lived in an ecosystem with a much larger plant-eater, Massospondylus, and its kin. Some of these dinosaurs weighed at least a ton.

Read more at Discovery News

Black Hole Twins?

Globular star clusters like M22, located about 10,600 light-years away in the constellation Sagittarius, may start out with hundreds of black holes, but gravity soon slingshots all but one of them away.

Or so scientists thought.

Newly discovered radio waves coming from M22 indicate the massive cluster has at least two -- and possibly as many as 100 -- black holes, each about 10 to 20 times the mass of the sun.

"This suggests that while some black holes might be ejected from globular clusters, this process may not be as efficient as some have thought. Globular clusters might actually turn out to be good places to look for black holes, rather than poor ones," Michigan State University astronomer Jay Strader told Discovery News.

Black holes are objects so densely packed with matter that not even photons of light can escape their gravitational grip. They are found by studying their impact on orbiting partner stars and surrounding material.

Each of M22's black holes has a companion object that is being cannibalized -- not good for the objects, but fortuitous for astronomers who were able to pick up telltale radio signals of the phenomenon.

Analysis shows there may be many more stellar-mass black holes, perhaps as many as 100, lurking inside the cluster, a spherical collection of stars orbiting around the galactic center.

"That many black holes will have an effect on the structure and evolution of M22," noted astronomer Stefan Umbreit with Northwestern University.

The black holes likely would keep the cluster's core from contracting and slow the evolution of the cluster as a whole.

M22's black holes are estimated to be about 1.6 light years from one another. Light travels at about 186,000 miles per second.

Read more at Discovery News

Stellar Fingerprinting Hints Nearest Star Hosts Planets

Astronomers have come up with a novel way to look for circumstantial evidence of rocky planets around sun-like stars. The "stellar fingerprinting" technique points to the nearest star to our sun, Alpha Centauri A, and one of the top contenders for possessing an Earth clone.

What has become apparent over the past few years is that stars with planets can be very slightly anemic --containing less iron -- compared to stars where planets are not detected.

The conventional wisdom is that a small fraction of these elements are locked up in rocky planets and asteroids that condensed out of a disk of dust and ice that encircled the newborn star. The elements never manage to fall into their star to chemically enrich it. Even a planet as massive as just a few Earths will leave a telltale deficiency in the star's chemistry.

With extraordinary precision, Ivan Ramirez of the University of Texas at Austin studied the makeup of 11 target stars. The exact mix of elements the stars yield could betray the presence of terrestrial and gas giant planets, and tell of the episodes in the star's birth they formed.

Ramirez's spectroscopic survey found that 15 percent of solar type stars have circumstantial evidence for terrestrial planets according to his chemical recipe based on our sun's spectral fingerprint. This is a bit lower than estimates by detection from NASA's prolific Kepler space observatory.

He used the binary stars 16 Cygni as a good test case. The one companion star where a planet was found has a slight deficiency of heavier elements as compared to its apparently planet-less twin star.

By far the most exciting stellar candidate is merely 4.3 light-years away, Alpha Centauri A, the largest star in the triple star system. Compared to 85 percent of solar twins studied in Ramirez's survey, it has the closest temperature and iron abundance as our sun.

Ramirez says that this strongly argues for the presence of one or more terrestrial planets circling the star. Searches are underway, but no evidence for planets have been teased out of the data yet.

Regardless, given Kepler's trawl of rocky planets it would be much more surprising not to find any rocky worlds orbiting Alpha Centauri A. Its closest companion star, Alpha Centauri B is far enough away to allow for stable planet orbits around either star.

Finding such a planet would send a seismic wave through the astronomical community. There would be a strong incentive to build ever-larger space telescopes to sample the planet's atmosphere, and in the much farther future, look for oceans and continents.

Because Alpha Centauri is as old as the sun, it would be natural to assume that a planet with atmospheric biotracers such as ozone, oxygen, methane and carbon dioxide would have time enough to evolve multicelled forms of life. If we found out that didn't happen on an Earth clone, it would strongly suggest that complex life is much more rare in the universe than some astrobiologists imagine.

This couldn't be answered without visiting such a world. And that could be accomplished within a reasonable amount of time if a probe could be built that could be accelerated to 10 percent the speed of light. Alpha Centauri A could be reached in a little over 40 years.

There is little doubt that microbes exist on other planets in our solar system. But being able to peruse a world to see Darwinian evolution played out over billions of years would be a scientific watershed of immeasurable impact.

Read more at Discovery News

Why Does Fall/Autumn Have Two Names?

Ambivalence over the name of the third season of the year reflects its status as a relatively new concept. As natural as it seems today, people haven't always thought of the year in terms of four seasons.

Fifteen hundred years ago, the Anglo-Saxons marked the passage of time with just one season: winter, a concept considered equivalent to hardship or adversity that metaphorically represented the year in its entirety. For example, in the Old English epic poem "Beowulf," the title character rescues a kingdom that had been terrorized by a monster for "12 winters."

According to "Folk Taxonomies in Early English" (Fairleigh Dickinson University Press, 2003) by Earl R. Anderson, the importance of winter in marking the passage of time is evidenced by the constancy of its name over time and across many languages. "Winter" probably derives from a root word meaning "wet" that traces back more than 5,000 years.

Summer is also a time-honored concept, though perhaps never quite as weighty a one as winter, and this is evidenced by greater ambivalence over its name. In Old English, the word "gear" connoted the warmer part of the year. This word gave way to the Germanic "sumer," which is related to the word for "half." Eventually, speakers of Middle English (the language used from the 11th to 15th centuries) conceived of the year in terms of halves: "sumer," the warm half, and "winter," the cold half. This two-season frame of reference dominated Western thinking as late as the 18th century.

Incidentally, Chinese culture also had a two-season framework, but there, the major seasonal polarity was autumn (symbolizing adversity) and spring (symbolizing regeneration), with little importance given to the extremes of summer and winter.

In the West, the transitional seasons, being more trivial, were "not fully lexicalized in the language" until much later, Anderson wrote. Lexicalization is the realization of an idea in a single word.

In 12th- and 13th-century Middle English, spring was called "lent" or "lenten" (but this also meant the religious observance), and fall, when it was considered a season at all, was called "haerfest" (which also meant the act of taking in crops). In the 14th and 15th centuries, "lenten" gave way to a panoply of terms, including "spring," "spryngyng tyme," "ver" (Latin for "green"), "primetemps" (French for "new time"), as well as more complicated descriptive phrases. By the 17th century, "spring" had won out.

In terms of seasons, the period spanning the transition from summer to winter had the weakest credentials of all, and so it got lexicalized last. "Autumn," a Latin word, first appears in English in the late 14th century, and gradually gained on "harvest." In the 17th century, "fall" came into use, almost certainly as a poetic complement to "spring," and it competed with the other terms.

Finally, in the 18th century, "harvest" had lost its seasonal meaning altogether, and "fall" and "autumn" emerged as the two accepted names for the third season. But by the 19th century, "fall" had become an "Americanism": a word primarily used in the United States and one that was frowned upon by British lexicographers.

The persistence of two terms for the third season in the United States, while somewhat of a mystery, may have something to do with the spread of English to the American continent at the very epoch when "fall" began jockeying for position with "autumn": the 17th century. At that time, both terms were adopted stateside, and the younger, more poetic "fall" gained the upper hand. Back in Britain, however, "autumn" won out. The continued acceptance of "autumn" in the United States may reflect the influence, or at least the proximity, of English culture and literature.

Read more at Discovery News

Oct 2, 2012

Length Matters in Gene Expression

A research team at Aarhus University reveals a surprising interplay between the ends of human genes: If a protein-coding gene is too short it becomes inactive! The findings also explain how some short genes have adapted to circumvent this handicap.

Gene ends communicate

Human genomes harbour thousands of genes, each of which gives rise to proteins when it is active. But which inherent features of a gene determine its activity? Postdoctoral Scholar Pia Kjølhede Andersen and Senior Researcher Søren Lykke-Andersen from the Danish National Research Foundation's Centre for mRNP Biogenesis and Metabolism have now found that the distance between the gene start, termed the 'promoter', and the gene end, the 'terminator', is crucial for the activity of a protein-coding gene. If the distance is too short, the gene is transcriptionally repressed and the output is therefore severely decreased. This finding outlines a completely new functional interplay between gene ends.

Small genes utilise specialised terminators

Fortunately, most human protein-coding genes are long and are therefore not repressed by this mechanism. However, some genes, e.g. 'replication-dependent histone genes', are very short. How do such genes express their information at all? Interestingly, many of these differ from the longer protein-coding genes by containing specialised terminators. And in fact, if such a specialised terminator replaces a normal terminator in a short gene context, the short gene is no longer transcriptionally repressed. It therefore appears that naturally occurring short genes have evolved 'their own' terminators to achieve high expression levels.

The new findings add to a complex molecular network of intragenic communication and help us to understand the basic function of genes.

Read more at Science Daily

The Science Behind Those Eye-Popping Northern Lights

Northern night skies have recently been alive with light. Those shimmering curtains get their start about 93 million miles away, on the sun.

An aurora borealis (aurora australis in the Southern Hemisphere) is precipitated by explosions on the surface of the sun, sometimes starting as solar flares, said Robert Nemiroff, an astrophysicist at Michigan Technological University and coauthor of NASA's Astronomy Picture of the Day website.

These flares release a burst of charged particles, or plasma, into the solar system. When they come our way, they whack into Earth's magnetosphere, which is made up of its own stream of charged particles. That collision causes particles to break free of the magnetosphere and cascade towar Earth's magnetic field lines, usually traveling toward the poles.

"The aurorae happen when these high-energy particles bap into atoms and molecules in the Earth's atmosphere, typically oxygen," Nemiroff said. Light is emitted as part of the reaction.

Those particles can also wreak havoc. "The plasma cloud can cause the Earth's magnetic field to fluctuate," Nemiroff said. "At worst, that can knock out satellites and even power grids."

Aurorae can happen anytime, but it's no surprise they are happening now.

"We are nearing the solar maximum, which is when the sun is at its most active," he said. Solar maximums come around every 11 years, but no one knows why.

Read more at Science Daily

Ancient Fortress Found in Spain

Spanish archaeologists have discovered an impressive structure with 4,200-year-old outer walls and six pyramid-shaped towers, representing the most architecturally advanced Bronze Age fortress.

Called La Bastida, the Spanish fortification system stood in the sierras of Totana, in the southeastern Murcia region. It was built with large stones and lime mortar and consisted of 10-foot-thick walls that were once 22 feet high and imposing pyramid-based towers. ‭

So far the archaeologists led by ‬Vicente Lull,‭ ‬professor of prehistory of the Autonomous University of Barcelona‭, have unearthed ‬ six towers along a length of‭ ‬230 feet,‭ although‬ the full perimeter of the fortification measured about 1,000 feet.

The entrance to the enclosure consisted of a passageway built with strong walls and large doors at the end,‭ ‬held shut with thick wooden beams.‭

One of the most relevant elements of the discovery was the secondary door, located near the main entrance.‭ ‬

The door's arch is in very good conditions and is the first one to be found in prehistoric Europe.

"Some of the fortification traits, such as the massive towers and the secondary door, could be found in some places of the Eastern Mediterranean slightly before 2200 B.C. This might show unexpected political relations between distant regions," Rafael Micó, professor of prehistory at the Autonomous University of Barcelona‭ and a member of the "La Bastida Project" direction team, told Discovery News.

Protecting a city located on top of a hill and extending over ‭ ‬10 acres, the fortress was designed‭ ‬by people experienced in fighting methods unknown in the West at those times.

The model is typical of ancient Mediterranean civilizations, including the second city of Troy in Turkey, and the urban world of the Middle East‭ (‬Palestine,‭ ‬Israel and Jordan‭)‬. According to the archaeologists, people from the East participated in the construction of the fortification.

"It was not until some‭ ‬400‭ ‬to‭ ‬800‭ ‬years later that civilizations like the Hittites and Mycenaeans,‭ ‬or city-states such as Ugarit,‭ ‬incorporated the innovative methods seen at La Basida into their military architecture," the archaeologists said in a statement.

Indeed, the fortress contained unique military features. For example, the lime mortar offered exceptional solidity to the construction,‭ ‬strongly holding the stones and making the wall impermeable,‭ ‬as well as eliminating any elements attackers could hold on to.‭

The postern gate,‭ ‬as a hidden and covered entrance,‭ ‬demanded great planning of the defensive structure as a whole and of the correct engineering technique to fit it perfectly into the wall.‭

All this indicates ‬ that La Bastida "was probably the most powerful city of Europe during the Bronze Age," the researchers said.

Previous excavations had already revealed the existence of a pool capable of storing over 100,000 gallons, and large houses and public buildings which were alternated with smaller constructions,‭ ‬all separated by entries,‭ ‬passageways and squares.‭

Read more at Discovery News

It Pays to Be a Nice Baboon

Like humans, baboons with good friends often enjoy better health and longer lives. Now research suggests the strength of a baboon's social circle depends less on its rank than its personality -- and being nice pays off.

"These results have allowed us to, for the first time in a wild primate, link personality characteristics, social skill and reproductive success," researcher Robert Seyfarth, of the University of Pennsylvania, said in a statement. "By being a nice baboon, you increase the likelihood of having strong social bonds, which in turn translates to a better chance of passing on your genes."

In baboons' hierarchical societies, females inherit their rank from their moms, which determines their access to food and mates. But a higher rank and a bigger network of kin does not always lead to greater fitness and reproductive success, the researchers said.

"In fact, dominance rank is not as good a predictor of reproductive outcomes as a close network of social relationships and stable relationships over time," Seyfarth explained. "So our question became 'What predicts having a strong network?'"

Seyfarth and his fellow researchers observed 45 female baboons in the Moremi Game Reserve in Botswana over the course of seven years, paying close attention to each baboon's friendly or aggressive tendencies. The team also studied how long the baboons and their offspring lived and measured their stress levels by testing their droppings for certain hormones. Based on trends they saw in the baboons' behavior, the researchers lumped the females into three personality groups: "nice," "aloof" and "loner."

Nice baboons were friendly to all others regardless of status -- they even reassured lower-ranking peers with grunts -- and they formed strong social bonds with long-term grooming partners. Aloof females also had consistent grooming partners as well, but they formed slightly weaker bonds and were more aggressive to others, often reserving their grunts for higher-ranking females with infants. Both nice and aloof females had the health and reproductive benefits associated with strong social bonds, the researchers said.

Meanwhile, loner females were the least friendly and formed the weakest social bonds. They often changed grooming partners and typically grunted only to appease higher-ranking females without infants. This personality type was linked to higher stress levels, lower offspring survival and shorter life spans, the researchers found.

Read more at Discovery News

Oct 1, 2012

How Immune Cells Defend Themselves Against HIV

A team of scientists led by virologists Prof. Oliver T. Fackler and Prof. Oliver T. Keppler from Heidelberg University Hospital have decoded a mechanism used by the human immune system to protect itself from HIV viruses. A protein stops the replication of the virus in resting immune cells, referred to as T helper cells, by preventing the transcription of the viral genome into one that can be read by the cell. The ground-breaking results provide new insights into the molecular background of the immunodeficiency syndrome AIDS and could open up starting points for new treatments.

The study has now been published -- ahead of print online -- in the international journal Nature Medicine.

Human immunodeficiency viruses attack different cells of the human immune system, most frequently, "T helper cells." These lymphocytes play a key role in immune defense, since they activate other immune cells upon contact with pathogens and set off subsequent immune responses. In the course of the HIV infection, they are continuously depleted until the immune system ultimately fails, culminating in AIDS with various infections.

In healthy people, the vast majority of T helper cells in the blood are in a resting state. They are not activated until they contact the pathogens against which they are specialized in defending. In the activated state, the cells are susceptible to HIV infection. "In contrast, resting T helper cells are immune to HIV: While the virus docks, and delivers its genetic information to the cell, the infection does not progress further. We have investigated why this is the case," explained Prof. Fackler, head of the working group at the Department of Infectious Diseases, Virology. Even if the T helper cells are activated later on, the virus does not replicate, because the genetic information of the virus is degraded during this period.

HIV genome cannot be transcribed into cell-compatible version

The team is headed by Prof. Fackler and Prof. Keppler, who moved from Heidelberg to the University Hospital in Frankfurt in April 2012 and now heads the Institute of Medical Virology there. The researchers discovered that the cellular protein SAMHD1 significantly contributes to protecting the resting immune cells. The protein is present in both resting and activated T helper cells and depletes nucleotides, the building blocks of genetic information. In the active phase the cells double their genetic information and divide, a process that depends on the continoues production of nucleotides. In the resting state, the cell does not require any nucleotides and stops their production, and SAMHD1 degrades the remaining nucleotides. "As a result, the HIV viruses most likely also lack the material they need to transcribe their genetic information into a version that can be used for the cell and to allow it to replicate," Fackler explained.

Read more at Science Daily

Stem Cells Improve Visual Function in Blind Mice

An experimental treatment for blindness, developed from a patient's skin cells, improved the vision of blind mice in a study conducted by Columbia ophthalmologists and stem cell researchers.

The findings suggest that induced pluripotent stem (iPS) cells -- which are derived from adult human skin cells but have embryonic properties -- could soon be used to restore vision in people with macular degeneration and other diseases that affect the eye's retina.

"With eye diseases, I think we're getting close to a scenario where a patient's own skin cells are used to replace retina cells destroyed by disease or degeneration," says the study's principal investigator, Stephen Tsang, MD, PhD, associate professor of ophthalmology and pathology & cell biology. "It's often said that iPS transplantation will be important in the practice of medicine in some distant future, but our paper suggests the future is almost here."

The advent of human iPS cells in 2007 was greeted with excitement from scientists who hailed the development as a way to avoid the ethical complications of embryonic stem cells and create patient-specific stem cells. Like embryonic stem cells, iPS cells can develop into any type of cell. Thousands of different iPS cell lines from patients and healthy donors have been created in the last few years, but they are almost always used in research or drug screening.

No iPS cells have been transplanted into people, but many ophthalmologists say the eye is the ideal testing ground for iPS therapies.

"The eye is a transparent and accessible part of the central nervous system, and that's a big advantage. We can put cells into the eye and monitor them every day with routine non-invasive clinical exams," Tsang says. "And in the event of serious complications, removing the eye is not a life-threatening event."

In Tsang's new preclinical iPS study, human iPS cells -- derived from the skin cells of a 53-year-old donor -- were first transformed with a cocktail of growth factors into cells in the retina that lie underneath the eye's light-sensing cells.

The primary job of the retina cells is to nourish the light-sensing cells and protect the fragile cells from excess light, heat, and cellular debris. If the retina cells die -- which happens in macular degeneration and retinitis pigmentosa -- the photoreceptor cells degenerate and the patient loses vision. Macular degeneration is a leading cause of vision loss in the elderly, and it is estimated that 30 percent of people will have some form of macular degeneration by age 75. Macular degeneration currently affects 7 million Americans and its incidence is expected to double by 2020.

In their study, the researchers injected the iPS-derived retina cells into the right eyes of 34 mice that had a genetic mutation that caused their retina cells to degenerate.

In many animals, the human cells assimilated into mouse retina without disruption and functioned as normal retina cells well into the animals' old age. Control mice that got injections of saline or inactive cells showed no improvement in retina tests.

"Our findings provide the first evidence of life-long neuronal recovery in a preclinical model of retinal degeneration, using stem cell transplant, with vision improvement persisting through the lifespan," Tsang says. "And importantly, we saw no tumors in any of the mice, which should allay one of the biggest fears people have about stem cell transplants: that they will generate tumors."

Tsang hopes to begin a clinical trial for macular degeneration patients in the next three years, after more preclinical testing in animal models.

Already a similar trial -- testing retina cells derived from embryonic stem cells -- has seen encouraging preliminary results. A paper from this study, published earlier this year, reported that the stem cells are safe and have potential to improve the vision of two patients with macular degeneration.

"These results are encouraging, but iPS cells could be a more attractive option than embryonic stem cells," Tsang says, "because patients may not need drugs to prevent rejection of the transplanted cells."

Regardless of which cell works better, the prospect of stem cell transplants may mean many people with macular degeneration may never lose their vision.

Read more at Science Daily

Clam Shells Yield Clues to Atlantic’s Climate History

Two Iowa State University graduate students are just back from the Gulf of Maine with another big catch of clam shells.

Shelly Griffin and Madelyn Mette recently boarded a lobster boat, dropped a scallop dredge into 30 meters of ocean water and pulled up load after load of Arctica islandica.

“These are the clams that end up in clam chowder,” said Alan Wanamaker, an assistant professor of geological and atmospheric sciences in the College of Liberal Arts and Sciences. Wanamaker studies paleoclimatology, the variations and trends of past climates and environments, with the goal of better understanding future climate changes.

The Iowa State researchers only need a few live, meaty clams for their studies. They’re really after the old, dead shells. Off the coast of Maine, clams can live up to 240 years, year after year adding another band to their shells, just like a tree adds another growth ring. In the colder waters of the North Atlantic near Iceland, the clams can live up to 500 years, recording even more information in what scientists call annual shell increments.

Wanamaker and his research team bring those shells back to Iowa State’s Stable Isotope Laboratory where they’re cleaned, sorted, measured, cut, polished, drilled and otherwise prepared for careful microscopic imaging, geochemical testing and radiocarbon analysis.

It turns out those shell increments are a lot like sensors at the bottom of the ocean – they record long records of information about the ocean, including growing conditions, temperatures and circulation patterns.

A paper published by Nature Communications in June 2012 reported how Wanamaker (the lead author) and an international team of researchers used radiocarbon data from shells to determine when clams collected north of Iceland were living in “young” or “old” water. Young water had been at the surface more recently and probably came from the Atlantic. Old water had been removed from the surface much longer and probably came from the Arctic Ocean.

The paper reports warmer, younger water from the Gulf Stream during the warmer Medieval Climate Anomaly from about A.D. 950 to 1250. The paper also reports that shell data showed older, colder water during Europe’s Little Ice Age from about A.D. 1550 to 1850.

The researchers’ interpretation of the data says the Gulf Stream carrying warm water from the subtropical Atlantic was strong in the medieval era, weakened during the Little Ice Age and strengthened again after A.D. 1940. Those fluctuations amplified the relative warmth and coolness of the times.

Wanamaker said a better understanding of the ocean’s past can help researchers understand today’s climate trends and changes.

“Is the natural variability only that, or is it influenced by burning fossil fuels?” he said. “Maybe we can understand what will happen in the next 100 years if we understand oceans over the past 1,000 years.”

And so Wanamaker – a former high school science teacher in Maine whose fascination with climate change sent him back to graduate school – works with students to carefully collect, process and study clam shells.

The research is painstaking – the shell increments are measured in millionths of a meter and microscopes are required at the most important steps. And the tools are sophisticated – two mass spectrometers measure shell fragments for different isotopes of carbon and oxygen. (Isotopes are elements with varying numbers of neutrons. Heavier isotopes of oxygen in the shell material generally correspond to colder ocean temperatures.)

“Isotopes are just wonderful tracers in nature,” Wanamaker said, noting he also takes isotope measurements for research projects across campus and beyond.

Read more at Science Daily

SARS-Like Virus May Come From Bats

The SARS-like virus that's caught the attention of health care workers worldwide appears to be related to a virus that infects bats in Southeast Asia.

Dutch virologists uncovered the genome sequence of the coronavirus that has killed one and sickened another patient; both had traveled to Saudi Arabia recently. The code reveals that the virus is more similar to two bat viruses than it is to sudden acutes respiratory syndrome.

"Bats harbor many coronaviruses, so it's logical to assume that bats are the natural reservoir" of the new virus, Ron Fouchier, who led the sequencing work, told National Public Radio.

Fouchier suspects there was an in-between animal that infected the patients. The World Health Organization said the virus so far does not appear to jump from person to person easily.

Scientists are in the process of developing a test that could be used to quickly identify new cases of the virus, Reuters reports.

"If any national authority is concerned about a patient who is under investigation, if they want to contact us, we can put them in touch with these laboratories and provide initial tests for any cases which are suspicious," WHO spokesman Glenn Thomas said.

Read more at Discovery News

Sep 30, 2012

Gene That Causes a Form of Deafness Discovered

Researchers at the University of Cincinnati and Cincinnati Children's Hospital Medical Center have found a new genetic mutation responsible for deafness and hearing loss associated with Usher syndrome type 1.

These findings, published in the Sept. 30 advance online edition of the journal Nature Genetics, could help researchers develop new therapeutic targets for those at risk for this syndrome.

Partners in the study included the National Institute on Deafness and other Communication Disorders (NIDCD), Baylor College of Medicine and the University of Kentucky.

Usher syndrome is a genetic defect that causes deafness, night-blindness and a loss of peripheral vision through the progressive degeneration of the retina.

"In this study, researchers were able to pinpoint the gene which caused deafness in Usher syndrome type 1 as well as deafness that is not associated with the syndrome through the genetic analysis of 57 humans from Pakistan and Turkey," says Zubair Ahmed, PhD, assistant professor of ophthalmology who conducts research at Cincinnati Children's and is the lead investigator on this study.

Ahmed says that a protein, called CIB2, which binds to calcium within a cell, is associated with deafness in Usher syndrome type 1 and non-syndromic hearing loss.

"To date, mutations affecting CIB2 are the most common and prevalent genetic cause of non-syndromic hearing loss in Pakistan," he says. "However, we have also found another mutation of the protein that contributes to deafness in Turkish populations.

"In animal models, CIB2 is found in the mechanosensory stereocilia of the inner ear -- hair cells, which respond to fluid motion and allow hearing and balance, and in retinal photoreceptor cells, which convert light into electrical signals in the eye, making it possible to see," says Saima Riazuddin, PhD, assistant professor in UC's department of otolaryngology who conducts research at Cincinnati Children's and is co-lead investigator on the study.

Researchers found that CIB2 staining is often brighter at shorter row stereocilia tips than the neighboring stereocilia of a longer row, where it may be involved in calcium signaling that regulates mechano-electrical transduction, a process by which the ear converts mechanical energy -- or energy of motion -- into a form of energy that the brain can recognize as sound.

"With this knowledge, we are one step closer to understanding the mechanism of mechano-electrical transduction and possibly finding a genetic target to prevent non-syndromic deafness as well as that associated with Usher syndrome type 1," Ahmed says.

Read more at Science Daily

Clonal Evolution in Maxillary Sinus Carcinoma

Knowing how tumors evolve can lead to new treatments that could help prevent cancer from recurring, according to a study published September 29 by the Translational Genomics Research Institute (TGen) and Scottsdale Healthcare.

TGen researchers tracked several years of tumor evolution in a 47-year-old male patient with maxillary sinus carcinoma (MSC), a rare cancer of the sinus cavities beneath the cheeks that often requires surgical removal that is disfiguring. Fewer than half of MSC patients live more than 5 years after diagnosis.

"The ability to characterize clonal evolution of this rare cancer and identify its Achilles' heel can significantly impact treatment, leading to more personalized medicine," according to the study published in the journal PLOS ONE.

Clonal evolution refers to the often-rapid genetic changes that occur in cancer cells, which continually mutate and, thus, frequently resist anti-cancer drug compounds intended to destroy them.

"If we can understand the genomic basis of how this cancer evolves, perhaps we can find new treatments that could help improve the longevity and quality of life for patients," said Dr. Glen Weiss, Clinical Associate Professor at TGen, and Director of Thoracic Oncology at Virginia G. Piper Cancer Center Clinical Trials at Scottsdale Healthcare, a partnership with TGen. Dr. Weiss is one of the study's senior co-authors.

MSC represents nearly four of every five cases of paranasal sinus cancers, which grow rapidly and invade nearby tissues but also are usually slow to spread to distant sites. Patients usually die from a local recurrence of the tumor, even after aggressive treatment.

"This is the first report to study the clonal population of MSC arising in longitudinal samples from the same patient," the study said. "One of the aims of this study was to closely follow disease progression and the clonally evolving metastases for molecular profiling and accumulation of data for future use in development of personalized treatment."

The patient in the study received conventional treatment, which included surgical removal of his tumors, radiation therapy and chemotherapy, and participation in a clinical trial.

Over time, however, the cancer spread to his upper right lung, lower left lung, left kidney, brain and part of his intestine. He eventually was hospitalized, received hospice care and prior to passing away gave permission to have his cancer studied after death in a rapid autopsy research program.

"Because his cancer resumed growth despite several courses of systemic chemotherapy and radiation therapy, we speculated that acquired secondary genetic changes evolved with the evolution of resistance to these therapies," said Dr. Michael Barrett, Associate Professor in TGen's Clinical Translational Research Division, and the study's other senior co-author.

Analysis of his tumors following surgeries, biopsies and autopsy revealed several genetic aberrations, including multiple copies of a region on chromosome 4q, which includes the KIT gene. KIT is an oncogene, a gene with the potential to cause cancer, and is a potential treatment target.

The authors suggest the results provide a unique description of how the drug resistant cancer cells replicate and progress to metastatic MSC. Additional findings included the loss of the gene PKP4, which is associated with increased tumor size.

"These results show that molecular analyses of patient samples can add to the information about the tumor and help us in tracking back the progression of the disease," the authors concluded. "Identification of selected genetic changes, and the biological processes they regulate arising in primary MSC tumors, will advance individualizing therapy and improve the outcome of patients with rare cancers."

"These kinds of cutting-edge studies are made possible through the collaboration of major research and clinical practices, such as the partnership between TGen and Scottsdale Healthcare," said Dr. Mark Slater, Vice President of Research at Scottsdale Healthcare.

Read more at Science Daily