Xenophilia (True Strange Stuff)

Blog of the real Xenophilius Lovegood, a slightly mad scientist

Archive for June 23rd, 2010

Sound creates light

Posted by Anonymous on June 23, 2010

pi100531 (10K)When light is used to transmit information, well established techniques of optical telecommunications are available: modulated light pulses travel along optical fibers, become weaker due to optical attenuation in the fiber and are “refreshed” in signal regeneration stations along the way, where the signals are amplified and filtered. This goal becomes more demanding when the light itself – or more precisely, its optical frequency – is the information, and when this information is to be transmitted with extreme precision. Here conventional amplification techniques reach their limits. Three researchers at Physikalisch-Technische Bundesanstalt (PTB) have now found an elegant solution: they employ so-called fiber Brillouin amplification, which is closely related to stimulated Brillouin scattering. The researchers inject pump light with a well-defined frequency into the far end of the fiber, so that the pump light travels in the opposite direction to the signal light, generating sound waves (acoustic phonons) in the glass fiber. The sound waves in turn scatter the pump light, enabling the existing signal photons to stimulate the emission of many more signal photons: thus a photon avalanche is created, which is kept going by the sound waves, and brings the frequency information to the remote end of the optical fiber with extremely small losses and very high precision. The PTB researchers have already demonstrated this technique on a 480 km optical fiber link: the relative measurement uncertainty they achieved is equivalent to a deviation of one second in 16 billion years. Now they plan to span even larger distances. The new method simplifies the comparison of newly developed optical clocks, which possess such a high frequency stability that traditional methods for frequency and time comparison via satellite are no longer sufficient. The technique is likely to have applications in other areas where precise synchronisation is needed, for example in radio astronomy. Experts in geodesy have already approached the PTB researchers with suggestions for joint projects.

The PTB physicists Harald Schnatz and Gesine Grosche are internationally leading experts in the precise measurement and transmission of frequencies via optical fibers. They use the optical frequency of the light, with some 195 · 1012 cycles per second, as the information. A first application of this new method was the remote measurement, conducted last year, of the so-called optical clock transition in a magnesium clock at the Leibniz University of Hannover. The scientists determined the characteristic frequency with which very cold magnesium atoms can be excited to a particular long-lived state, by a measurement from PTB via 73 km optical fiber. It is important to measure such frequencies accurately as they can in principle be used to “generate” seconds. “For such measurements, there are femtosecond frequency comb generators at both ends, which produce a fixed phase relationship between the transmitted light and the frequency standards on site”, explains Harald Schnatz. The frequency standards on site are the new magnesium clock in Hanover and an optical clock at PTB. The different frequencies of the two are synchronized with the aid of femtosecond frequency comb generators, which can be compared to a gear mechanism. Schnatz adds: “At first we were astonished how well this complete system works.” …

via Physikalisch-Technische Bundesanstalt (PTB).

Posted in Physics, Technology | Leave a Comment »

Ignoring stress leads recovering addicts to more cravings

Posted by Anonymous on June 23, 2010

http://blog.splitgames.fr/wp-content/uploads/2007/10/stress.jpgRecovering addicts who avoid coping with stress succumb easily to substance use cravings, making them more likely to relapse during recovery, according to behavioral researchers.

“Cravings are a strong predictor of relapse,” said H. Harrington Cleveland, associate professor of human development, Penn State. “The goal of this study is to predict the variation in substance craving in a person on a within-day basis. Because recovery must be maintained ‘one day at a time,’ researchers have to understand it on the same daily level.”

Cleveland and his colleague Kitty S. Harris, director, Center for the Study of Addiction and Recovery, Texas Tech University, used data from a daily diary study of college students who are recovering addicts to identify the processes that trigger cravings and prevent some addicts from building a sustained recovery.

The researchers found that how addicts cope with stress — either by working through a problem or avoiding it — is a strong predictor of whether they will experience cravings when faced with stress and negative mood.

“Whether you avoid problems or analyze problems not only makes a big difference in your life but also has a powerful impact on someone who has worked hard to stay away from alcohol and other drugs,” explained Cleveland. “When faced with stress, addicts who have more adaptive coping skills appear to have a better chance of staying in recovery.” The findings appeared in a recent issue of Addictive Behaviors.

Researchers supplied Palm Pilots to 55 college students who were in recovery from substance abuse ranging from alcohol to cocaine and club drugs. The students were asked to record the their daily cravings for alcohol and other drugs, as well as the intensity of negative social experiences — hostility, insensitivity, interference, and ridicule — and their general strategies for coping with stress.

“We looked at variations in the number of cravings across days and found that these variations are predicted by stressful experiences,” said Cleveland. “More importantly, we found that the strength of the daily link between experiencing stress and the level of cravings experienced is related to the participants’ reliance on avoidance coping.”

Statistical analyses of the survey data suggests that the magnitude of the link between having a stressful day and experiencing substance use cravings doubles for recovering addicts who cope with stress by avoiding it.

“We found that addicts who deal with stress by avoiding it have twice the number of cravings in a stressful day compared to persons who use problem solving strategies to understand and deal with the stress,” explained Cleveland. “Avoidance coping appears to undercut a person’s ability to deal with stress and exposes that person to variations in craving that could impact recovery from addiction.”

According to Cleveland, the findings suggest the impulse to avoid stress is never going to help recovering addicts because stressful experiences cannot be avoided.

“If your basic life strategy is to avoid stress, then your problems will probably end up multiplying and causing you more problems,” he added.

via Ignoring stress leads recovering addicts to more cravings.

Posted in Health, Mind | Leave a Comment »

Roman fort found in Cornwall ‘rewrites history’

Posted by Anonymous on June 23, 2010

Roman coin discovered in CornwallA Roman fort which has been discovered in Cornwall is challenging previous historical views about the South West.

Pottery and pieces of slag have been found at the undisclosed location near St Austell, suggesting an ironworks.

Experts said the discovery challenges previous thinking about the region’s history as it had been thought Romans did not settle much beyond Exeter.

John Smith, from Cornwall Historic Environment Service, said: “This is a major discovery, no question about it.”

‘Crucial’ find

Mr Smith said: “For Roman Britain it’s an important and quite crucial discovery because it tells us a lot about Roman occupation in the South West that was hitherto completely unexpected.

“The other Roman sites we know about [in Cornwall] have occupation in the 1st Century AD, of about AD50 to AD80, and that fits in with what we know about Exeter.

“In finding the pottery and glass, it’s saying the occupation is much longer and goes from AD60 up to about AD250, which turns the whole thing on its head.

“It certainly means a rewrite of history in the South West.”

The site had previously been regarded as an Iron Age settlement, but the recent discovery of pottery and glass was found to be of Roman origin.

Archaeological enthusiast Jonathan Clemes discovered various artefacts by studying the earth after it had been ploughed.

He said: “You’ve got to know your pottery.

“If you come across a bit of pottery and you know what it is, it can tell you a great deal about the activity that went on in that area.”

Following the discovery of the artefacts a geophysical survey of the site was conducted, which uncovered a fort, marching camp and various annexes.

Mr Smith said that prior to this discovery, it was believed that Roman forts had only been positioned close to the Devon border, because after settling for about 30 years, the Romans left the region for south Wales.

It will now be considered whether to excavate the area, or to leave it for a future excavation when techniques have advanced.

via BBC News – Roman fort found in Cornwall ‘rewrites history’.

Posted in Archaeology | Leave a Comment »

Apostle images from 4th century found under street in Italy

Posted by Anonymous on June 23, 2010

icon of the Apostle John

Archaeologists exploring a Christian catacomb under a residential Roman street have unearthed the earliest known images of the apostles Andrew and John.

Using a newly developed laser to burn away centuries of calcium deposits without damaging the paintings beneath, the team found the late 4th-century images in the richly decorated tomb of a Roman noblewoman.

“John’s young face is familiar, but this is the most youthful portrayal of Andrew ever seen, very different from the old man with grey hair and wrinkles we know from medieval painting,” said project leader Barbara Mazzei.

Discovered in the 1950s and as yet unseen by the public, the St Tecla catacomb is accessed through the unmarked basement door of a drab office building, beyond which dim corridors packed with burial spots wind off through damp tufa stone.

The catacomb is close to the basilica of St Paul’s Outside the Walls, where bones discovered in a sarcophagus have been dated to the first or second century and attributed to St Paul.

Working under the supervision of the Vatican’s pontifical commission for sacred archaeology, Mazzei first exposed images of fellow apostles Peter and Paul, as well as Jesus, and biblical scenes set against rich ochre, red and black backgrounds – colours commonly associated with imperial Roman art.

Catacomb archeological superintendent Fabrizio Bisconti points to  frescoes discovered with the earliest known icons of the Apostles Peter  and Paul in a catacomb located under a modern office building in a  residential neighborhood of Rome, Tuesday, June, 22, 2010. Restorers  said Tuesday they had unearthed the 4th-century images using a new laser  technique that allowed them to burn off centuries of white calcium  deposits without damaging the dark colors of the original paintings  underneath. The paintings adorn what is believed to be the tomb of a  Roman noblewoman and represent some of the earliest evidence of devotion  to the apostles in early Christianity.“The laser can be calibrated to remove certain colours, in this case the white of the calcium, which just fell away. We are used to finding faded colours, but here they are exceptional,” she said.

As the calcium was burned off, John and Andrew appeared on the same ceiling panel as Peter and Paul.

A cameraman films a painting discovered with the earliest known icons of the Apostles Peter and Paul in a catacomb located under a modern office building in a residential neighborhood of Rome, Tuesday, June, 22, 2010. Restorers said Tuesday they had unearthed the 4th-century images using a new laser technique that allowed them to burn off centuries of white calcium deposits without damaging the dark colors of the original paintings underneath. The paintings adorn what is believed to be the tomb of a Roman noblewoman and represent some of the earliest evidence of devotion to the apostles in early Christianity.We already know earlier images of Peter and Paul from group paintings, but all previously known images of Andrew and John date to the mid 5th century,” said Mazzei. “We assume it is them because they were the most important apostles after Peter and Paul and would have found space alongside them here.”

Mazzei said the tomb was built by a noblewoman as Rome was switching from paganism to Christianity. “This catacomb was not a clandestine burial place, in fact they never were, that was an invention of Ben Hur,” she said.

via Apostle images from 4th century found under street in Italy | Science | The Guardian.

It was announced at a press conference yesterday in Rome that the oldest known images of the apostles Peter, Andrew and John have been uncovered in one of the city’s Christian catacombs.

The images date from the late fourth century AD and were found in the underground chambers of the catacombs of Santa Tecla, in the south of the city near San Paolo Fuori le Mura on via Ostiense. …

In what seems like a strange coincidence, two astonishing discoveries providing evidence of the life of Saint Paul have been made within days of each other at two religious sites in Rome. First of all a fourth century fresco of the Christian saint was uncovered on 19 June at the Catacombs of Santa Thekla in Rome. Paul – formerly Saul – was a Hellenic Jew who converted to Christianity after his religious experience on the road to Damascus but was then executed during the reign of the emperor Nero between 60-67 AD. The Christian catacombs of Santa Thekla, closed to the public, are reported to be full of frescoes, although most are in need of restoration. It was during an ongoing preservation project that the discovery was made.

via http://heritage-key.com/category/tags/barbara-mazzei

Catacomb archeological superintendent Fabrizio Bisconti points to frescoes discovered with the earliest known icons of the Apostles Peter and Paul in a catacomb located under a modern office building in a residential neighborhood of Rome, Tuesday, June, 22, 2010. Restorers said Tuesday they had unearthed the 4th-century images using a new laser technique that allowed them to burn off centuries of white calcium deposits without damaging the dark colors of the original paintings underneath. The paintings adorn what is believed to be the tomb of a Roman noblewoman and represent some of the earliest evidence of devotion to the apostles in early Christianity.

Posted in Archaeology, Religion | Leave a Comment »

God particle signal is simulated as sound

Posted by Anonymous on June 23, 2010

Simulated Higgs production at Atlas (Cern)Scientists have simulated the sounds set to be made by sub-atomic particles such as the Higgs boson when they are produced at the Large Hadron Collider.

Their aim is to develop a means for physicists at Cern to “listen to the data” and pick out the Higgs particle if and when they finally detect it.

Dr Lily Asquith modelled data from the giant Atlas experiment at the LHC.

She worked with sound engineers to convert data expected from collisions at the LHC into sounds.

“If the energy is close to you, you will hear a low pitch and if it’s further away you hear a higher pitch,” the particle physicist told BBC News.

“If it’s lots of energy it will be louder and if it’s just a bit of energy it will be quieter.”

The £6bn LHC machine on the Swiss-French border is designed to shed light on fundamental questions in physics.

It is housed in a 27km-long circular tunnel, where thousands of magnets steer beams of proton particles around the vast “ring”.

At allotted points around the tunnel, the beams cross paths, smashing together near four massive “experiments” that monitor these collisions for interesting events.

Scientists are hoping that new sub-atomic particles will emerge, revealing insights into the nature of the cosmos.

Atlas is one of the experiments at the LHC. An instrument inside Atlas called the calorimeter is used for measuring energy and is made up of seven concentric layers.

Each layer is represented by a note and their pitch is different depending on the amount of energy that is deposited in that layer.

The process of converting scientific data into sounds is called sonification.

Dr Asquith and her team have so far generated a number of simulations based on predictions of what might happen during collisions inside the LHC.

The team is only now feeding in real results from real experiments.

via BBC News – God particle signal is simulated as sound.

Posted in Physics | Leave a Comment »

World’s Scientists Admit They Just Don’t Like Mice

Posted by Anonymous on June 23, 2010

Nearly 700 scientists representing 27 countries convened at the University of Zurich Monday to formally announce that their experimentation on mice has been motivated not by a desire to advance human knowledge, but out of sheer distaste for the furry little rodents.

“As a man of science, I deal with facts, and the fact is that mice are gross,” said Dr. Douglas White, chair of the Oxford biogenetics department and lifelong mouse-hater. “They’re squirmy, scurrying little vermin, and they make my skin crawl. I speak for all of my assembled colleagues when I say that the horrible little things deserve the worst we can dish out.”

According to a 500-word statement, scientists hate mice for “their beady little eyes,” “their repulsive tails,” and “the annoying little squeaking sounds they make.” …

“The truth is, mice are particularly ill-suited for our tissue study,” Gresham added. “We could construct a computer model that would yield more accurate results, but we don’t care.” …

via World’s Scientists Admit They Just Don’t Like Mice | The Onion – America’s Finest News Source.

Posted in Humor | Leave a Comment »

 
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