Friday, February 11, 2011

Speak a lot of languages - it’s easier

0 comentarios
Bilinguals find it easier to learn a third language, as they gain a better aptitude for languages, a new study from the University of Haifa reveals.

Prof. Salim Abu-Rabia and Ekaterina Sanitsky of the Department of Special Education, who conducted the study, set out to examine what benefits bilingualism might have in the process of learning a third language. They hypothesized that students who know two languages would have an easier time gaining command of a third language than would students who are fluent in only one language.

For this study, two groups of 6th grade students in Israel were chosen to represent a sample of students studying English as a foreign language. The first group comprised 40 students, immigrants from the FSU whose mother tongue is Russian and who speak fluent Hebrew as a second language. The second group comprised 42 native Hebrew-speaking students with no fluency in another language, besides the English being studied in school as a foreign language.

Each participant took part in two meetings: a group meeting and an individual meeting. At the group meeting, the participants were given tests that assessed reading strategy and familiarity with the orthography of each language - Hebrew, English and Russian for the Russian speakers, and were asked to fill out personal questionnaires. At the individual student meetings, the researchers gave the Hebrew-only speakers a test in Hebrew and English, and the same tests with Russian added were given to those who were Russian speakers.

After comparing and merging the results of these tests, the researchers were able to conclude that those students whose mother tongue was Russian demonstrated higher proficiency not only in the new language, English, but also in Hebrew. They found that the total average between the tests of the two groups was above 13% in the Russian-speakers’ favor. Some of the specific tests showed particularly wide gaps in command of English, the Russian speakers achieving the higher scores: in writing skills, there was a 20% gap between the scores; in orthographic ability, the gap reached up to 22%; and in morphology it soared as high as 35%. In the intelligence test (the Raven Progressive Matrices test), the gap was over 7% on the side of the Russian speakers. According to the researchers, these results show that the more languages a person learns, the higher his or her intelligence will be.

This team of scholars also noted that the fact that the Russian speakers had better Hebrew skills than the Hebrew speakers themselves indicates that acquiring a mother tongue and preserving that language in a bilingual environment does not come at the expense of learning a second language - Hebrew in this case. In fact, the opposite is true: fluency and skills in one language assist in the language acquisition of a second language, and possessing skills in two languages can boost the learning process of a third language.

“Gaining command of a number of languages improves proficiency in native languages,” Prof. Abu-Rabia explained. “This is because languages reinforce one another, and provide tools to strengthen phonologic, morphologic and syntactic skills. These skills provide the necessary basis for learning to read. Our study has also shown that applying language skills from one language to another is a critical cognitive function that makes it easier for an individual to go through the learning process successfully. Hence, it is clear that tri-lingual education would be most successful when started at a young age and when it is provided with highly structured and substantive practice,” he concluded.

University of Haifa

Internet addresses: An inevitable shortage, but an uneven one

0 comentarios

As Internet authorities prepare to announce that they have handed over all of the available addresses, a USC research group that monitors address usage has completed the latest in its series of Internet censuses.

There is some good news, according to computer scientist John Heidemann, who heads a team at the USC Viterbi School of Engineering Information Sciences Institute that has just released its results in the form of a detailed outline, including a 10-minute video and an interactive web browser that allows users to explore the nooks and crannies of Internet space themselves.


Heidemann who is a senior project leader at ISI and a research associate professor in the USC Viterbi School of Engineering Department of Computer Science, says his group has found that while some of the already allocated address blocks (units of Internet real estate, ranging from 256 to more than 16 million addresses) are heavily used, many are still sparsely used. "Even allowing for undercount," the group finds, "probably only 14 percent of addresses are visible on the public Internet."

Nevertheless, "as full allocation happens, there will be pressure to improve utilization and eventually trade underutilized areas," the video shows. These strategies have limits, the report notes. Better utilization, trading, and other strategies can recover "twice or four times current utilization. But requests for address double every year, so trading will only help for two years. Four billion addresses are just not enough for 7 billion people."

The IPv6 protocol allows many, many more addresses – 1000 1000 trillion – but may involve transition costs.

Heidemann's group report comes as the Number Resource Organization (NRO) and he Internet Assigned Numbers Authority (IANA) are preparing to make an announcement saying they have given out all the addresses, passing on most to regional authorities.

The ISI video offers a thorough background in the hows and whys of the current IPv4 Internet address system, in which each address is a number between zero and 2 to the 32nd power (4,294,967,295), usually written in "dotted-decimal notation" as four base-10 numbers separated by periods.

Heidemann, working with collaborator Yuri Pradkin and ISI colleagues, produced an earlier Internet census in 2007, following on previous work at ISI -- the first complete census since 1982. To do it, they sent a message ('ping') each to each possible Internet address. The video explains the pinging process.

At the time, some 2.8 million of the 4.3 million possible addresses had been allocated; today more than 3.5 million are allocated. The current effort, funded by Department of Homeland Security Science and Technology Directorate and the NSF, was carried out by Aniruddh Rao and Xue Cui of ISI, along with Heidemann. Peer-reviewed analysis of their approach appeared in ACM Internet Measurements Conference, 2008.

(Photo: USC Information Sciences Institute)

University of Southern California

Want more efficient muscles? Eat your spinach

0 comentarios
After taking a small dose of inorganic nitrate for three days, healthy people consume less oxygen while riding an exercise bike. A new study in the February issue of Cell Metabolism traces that improved performance to increased efficiency of the mitochondria that power our cells.

The researchers aren't recommending anyone begin taking inorganic nitrate supplements based on the new findings. Rather, they say that the results may offer one explanation for the well-known health benefits of fruits and vegetables, and leafy green vegetables in particular.

"We're talking about an amount of nitrate equivalent to what is found in two or three red beets or a plate of spinach," said Eddie Weitzberg of the Karolinska Institutet in Sweden. "We know that diets rich in fruits and vegetables can help prevent cardiovascular disease and diabetes but the active nutrients haven't been clear. This shows inorganic nitrate as a candidate to explain those benefits."

In fact, up until recently nitrate wasn't thought to have any nutritional value at all. It has even been suggested that this component of vegetables might be toxic. But Weitzberg and his colleague Jon Lundberg earlier showed that dietary nitrate feeds into a pathway that produces nitric oxide with the help of friendly bacteria found in our mouths. Nitric oxide has been known for two decades as a physiologically important molecule. It opens up our blood vessels to lower blood pressure, for instance.

The new study offers yet another benefit of nitrate and the nitric oxides that stem from them. It appears that the increased mitochondrial efficiency is owed to lower levels of proteins that normally make the cellular powerhouses leaky. "Mitochondria normally aren't fully efficient," Weitzberg explained. "No machine is."

Questions do remain. The new results show that increased dietary nitrate can have a rather immediate effect. But it's not yet clear what might happen in people who consume higher levels of inorganic nitrate over longer periods of time. Weitzberg says it will be a natural next step to repeat the experiment in people with conditions linked to mitochondrial dysfunction, including diabetes and cardiovascular disease, to see if they too enjoy the benefits of nitrates.

"Among the more consistent findings from nutritional research are the beneficial effects of a high intake of fruit and vegetables in protection against major disorders such as cardiovascular disease and diabetes," the researchers concluded. "However, the underlying mechanism(s) responsible for these effects is still unclear, and trials with single nutrients have generally failed. It is tempting to speculate that boosting of the nitrate-nitrite-NO pathway may be one mechanism by which vegetables exert their protective effects."

As an interesting aside, Weitzberg says that the benefits of dietary nitrates suggest that powerful mouthwashes may have a downside. "We need oral bacteria for the first step in nitrate reduction," he says. "You could block the effects of inorganic nitrate if you use a strong mouthwash or spit [instead of swallowing your saliva]. In our view, strong mouthwashes are not good if you want this system to work."



0 comentarios

In an effort to better understand the dynamics of complex networks, scientists have developed a mathematical model to describe interactions within ecological food webs. This research, performed by Northwestern University physics professor Adilson Motter and his student, Sagar Sahasrabudhe, is published in the January 25 issue of Nature Communications. The work illustrates how human intervention may effectively aid species conservation efforts.

University of Alberta researchers determined that a fossilized dinosaur bone found in New Mexico confounds the long established paradigm that the age of dinosaurs ended between 65.5 and 66 million years ago.

The U of A team, led by Larry Heaman from the Department of Earth and Atmospheric Sciences, determined the femur bone of a hadrosaur as being only 64.8 million years old. That means this particular plant eater was alive about 700,000 years after the mass extinction event many paleontologists believe wiped all non-avian dinosaurs off the face of earth, forever.

Heaman and colleagues used a new direct-dating method called U-Pb (uranium-lead) dating. A laser beam unseats minute particles of the fossil, which then undergo isotopic analysis. This new technique not only allows the age of fossil bone to be determined but potentially can distinguish the type of food a dinosaur eats. Living bone contains very low levels of uranium but during fossilization (typically less than 1000 years after death) bone is enriched in elements like uranium. The uranium atoms in bone decay spontaneously to lead over time and once fossilization is complete the uranium-lead clock starts ticking. The isotopic composition of lead determined in the hadrosaur's femur bone is therefore a measure of its absolute age.

Currently, paleontologists date dinosaur fossils using a technique called relative chronology. Where possible, a fossil's age is estimated relative to the known depositional age of a layer of sediment in which it was found or constrained by the known depositional ages of layers above and below the fossil-bearing horizon. However, obtaining accurate depositional ages for sedimentary rocks is very difficult and as a consequence the depositional age of most fossil horizons is poorly constrained. A potential weakness for the relative chronology approach is that over millions of years geologic and environmental forces may cause erosion of a fossil-bearing horizon and therefore a fossil can drift or migrate from its original layer in the strata. The researchers say their direct-dating method precludes the reworking process.

It's widely believed that a mass extinction of the dinosaurs happened between 65.5 and 66 million years ago. It's commonly believed debris from a giant meteorite impact blocked out the Sun, causing extreme climate conditions and killing vegetation worldwide.

Heaman and his research colleagues say there could be several reasons why the New Mexico hadrosaur came from a line of dinosaurs that survived the great mass extinction events of the late Cretaceous period (KT extinction event). Heaman says it's possible that in some areas the vegetation wasn't wiped out and a number of the hadrosaur species survived. The researchers also say the potential survival of dinosaur eggs during extreme climatic conditions needs to be explored.

Heaman and his colleagues believe if their new uranium-lead dating technique bears out on more fossil samples then the KT extinction paradigm and the end of the dinosaurs will have to be revised.

(Photo: U. Alberta)

University of Alberta


0 comentarios

So you think global warming is a big problem? What could happen if a 25-million-ton chunk of rock slammed into Earth? When something similar happened 65 million years ago, the dinosaurs and other forms of life were wiped out.

“A collision with an object of this size traveling at an estimated 30,000 to 40,000 mile per hour would be catastrophic,” according to NASA researcher and New York City College of Technology (City Tech) Associate Professor of Physics Gregory L. Matloff. His recommendation? “Either destroy the object or alter its trajectory.”

Dr. Matloff, whose research includes the best means to avert such a disaster, believes that diverting such objects is the wisest course of action. In 2029 and 2036, the asteroid Apophis (named after the Egyptian god of darkness and the void), at least 1,100 feet in diameter, 90 stories tall, and weighing an estimated 25 million tons, will make two close passes by Earth at a distance of about 22,600 miles.

“We don’t always know this far ahead of time that they’re coming,” Dr. Matloff says, “but an Apophis impact is very unlikely.” If the asteroid did hit Earth, NASA estimates, it would strike with 68,000 times the force of the atom bomb that leveled Hiroshima. A possibility also exists that when Apophis passes in 2029, heating as it approaches the sun, it could fragment or emit a tail, which would act like a rocket, unpredictably changing its course. If Apophis or its remnants enter one of two “keyholes” in space, impact might happen when it returns in 2036.

Large chunks of space debris whizzing by the planet, called Near-Earth Objects (NEOs), are of real concern. NASA defines NEOs as comets and asteroids that enter Earth’s neighborhood because the gravitational attraction of nearby planets affects their orbits. Dr. Matloff favors diverting rather than exploding them because the latter could create another problem — debris might bathe Earth in a radioactive shower.

Dr. Matloff’s research indicates that an asteroid could be diverted by heating its surface to create a jet stream, which would alter its trajectory, causing it to veer off course. In 2007, with a team at the NASA Marshall Space Flight Center in Huntsville, Alabama, he investigated methods of deflecting NEOs. The team theorized that a solar collector (SC), which is a two-sail solar sail configured to perform as a concentrator of sunlight, could do the trick. Constructed of sheets of reflective metal less than one-tenth the thickness of a human hair, an SC traveling alongside an NEO for a year would concentrate the sun’s rays on the asteroid, burn off part of the surface, and create the jet stream.

To do that, it is necessary to know how deeply the light would need to penetrate the NEO’s surface. “A beam that penetrates too deeply would simply heat an asteroid,” explains Dr. Matloff, “but a beam that penetrates just the right amount — perhaps about a tenth of a millimeter — would create a steerable jet and achieve the purpose of deflecting the asteroid.”

For the past year, Dr. Matloff and a team of City Tech scientists have been experimenting with red and green lasers to see how deeply they penetrate asteroidal rock, using solid and powdered (regolith) samples from the Allende meteorite that fell in Chihuahua, Mexico in 1969. Dr. Denton Ebel, meteorite curator at the American Museum of Natural History in New York City, provided the samples.

Assistant Professor of Physics Lufeng Leng, a photonics and fiber optics researcher, along with student Thinh Lê, an applied mathematics senior, used lasers to obtain optical transmission measurements (the fraction of light passing through the asteroidal material). Their research was supported by a Professional Staff Congress-City University of New York research grant.

“To my knowledge,” says Dr. Matloff, “this is the first experimental measurement of the optical transmission of asteroid samples. Dr. Ebel is encouraging other researchers to repeat and expand on this work.”

In a related study, Dr. Leng and her student (whose research was partially supported by City Tech’s Emerging Scholars Program) narrowed the red laser beam and scanned the surface of a thin-section Allende sample, discovering that differences in the depth of transmitted light exist, depending on the composition of the material through which the beam passes. From their results, they concluded that lasers aimed from a space probe positioned near an NEO could help determine its surface composition. Using that information, solar sail technology could more accurately focus the sun’s rays to penetrate the asteroid’s surface to the proper depth, heating it to the correct degree for generating a jet stream that would re-direct the asteroid.

“For certain types of NEOs, by Newton’s Third Law, the jet stream created would alter the object’s solar orbit, hopefully converting an Earth impact to a near miss,” Dr. Matloff states. However, he cautions, “Before concluding that the SC will work as predicted on an actual NEO, samples from other extraterrestrial sources must be analyzed.”

Dr. Matloff presented a paper on the results of the City Tech team’s optical transmission experiments, “Optical Transmission of an Allende Meteorite Thin Section and Simulated Regolith,” at the 73rd Annual Meeting of the international Meteoritical Society, held at the American Museum of Natural History and the Park Central Hotel in New York City.

“At present,” he adds, “a debate is underway between American and Russian space agencies regarding Apophis. The Russians believe that we should schedule a mission to this object probably before the first bypass because Earth-produced gravitational effects during that initial pass could conceivably alter the trajectory and properties of the object. On the other hand, Americans generally believe that while an Apophis impact is very unlikely on either pass, we should conduct experiments on an asteroid that runs no risk of ever threatening our home planet.”

(Photo: Michele Forsten)

The City University of New York


0 comentarios
New research in the FASEB Journal suggests that there are extensive but reversible changes in the heart when it is exposed to low oxygen levels similar to those caused by many diseases.

From the highest mountaintop comes a new research report in the FASEB Journal ( that gets to the bottom of what happens to the hearts of people when exposed to low-levels of oxygen, such as those on Mount Everest or in the intensive care unit of a hospital. In the study, researchers monitored subjects who spent time at the Mount Everest Base Camp and found that the low-level oxygen conditions at the base came caused changes in heart function resembling what is seen in conditions that severely restrict the amount of oxygen to the heart, such as cystic fibrosis, chronic obstructive pulmonary disease, emphysema, pneumonia, and some forms of heart failure. The good news, however, is that in six months, heart function for these mountain climbers returned to normal. This suggests that the same could be true for people in the ICU if the underlying cause can be corrected.

"Understanding how the heart is able to cope with low oxygen will allow better treatment for a range of heart conditions, including types of heart failure and heart attacks," said Cameron Holloway, MBBS, MRCP, FRACP, D.Phil., a scientist involved in the research from the Department of Physiology, Anatomy and Genetics at the University of Oxford in the United Kingdom. "We also hope to use this information to show how the heart is able to cope with other diseases associated with low oxygen levels. These experiments not only allow us to see the effects on healthy hearts, but also contribute to our understanding of how the body copes with diseases."

Scientists studied 14 physicians and scientists as they trekked to the Mount Everest Base Camp. Before and after the trek, heart scans (using a combination of echocardiography, cardiac magnetic resonance, and a specialized scan that assesses chemicals in the heart) were administered to each subject. After the trek, none of these healthy subjects showed any symptoms of heart problems, but the heart scans revealed fuel levels and changes in heart function consistent with what is seen in heart failure patients. All study protocols were repeated within 48 hours post-trek and again six months later. All of the changes returned to baseline values six months after the climb, suggesting that cardiac changes due to hypoxia are extensive but reversible. This also suggests that heart problems experienced by seriously ill patients may be reversible once oxygen levels in the bloodstream are returned to normal.

"Changes in human physiology under extreme conditions that return to normal after re-adjustment have been seen in other environments. For instance, in U.S. Space Shuttle astronauts VO2 peak and peak power input changes after exposure to microgravity return to normal within weeks after reconditioning in normal gravity," said Millie Hughes-Fulford, Ph.D., NASA Science Astronaut; Professor, Department of Biochemistry and Biophysics, UCSF; Director, Laboratory of Cell Growth, VAMC/UCSF; and editorial board member of the FASEB Journal. "The finding of changes in cardiac function after a Mt. Everest trek within months, suggests that decreased PCr/ATP in patients caused by sustained hypoxia may reverse once oxygen levels return to normal."





Selected Science News. Copyright 2008 All Rights Reserved Revolution Two Church theme by Brian Gardner Converted into Blogger Template by Bloganol dot com