Di seguito gli interventi pubblicati in questa sezione, in ordine cronologico.
Most people may think the speed of light is constant, but this is only the case in a vacuum, such as space, where it travels at 671million mph.
However, when it travels through different substances, such as water or solids, its speed is reduced, with different wavelengths (colours) travelling at different speeds.
The green laser is shown as it leaves the ruby crystal.
In addition, it has also been observed, but is not widely appreciated, that light can be dragged when it travels through a moving substance, such as glass, air or water – a phenomenon first predicted by Augustin-Jean Fresnel in 1818 and observed a hundred years later.
Prof. Miles Padgett in the Optics Group in the School of Physics & Astronomy, said: “The speed of light is a constant only in vacuum . When light travels through glass, movement of the glass drags the light with it too.
“Spinning a window as fast as you could is predicted to rotate the image of the world behind it ever so slightly. This rotation would be about a millionth of a degree and imperceptible to the human eye.”
In research detailed in the latest edition of the journal Science, researchers Dr Sonja Franke-Arnold, Dr Graham Gibson and Prof Padgett, in collaboration with their colleague Professor Robert Boyd at the Universities of Ottowa and Rochester, took a different approach and set up an experiment: shining a primitive image made up of the elliptical profile of a green laser through a ruby rod spinning on its axis at up to 3,000 rpm.
Once the light enters the ruby, its speed is slowed down to around the speed of sound (approximately 741mph) and the spinning motion of the rod drags the light with it, resulting in the image being rotated by almost five degrees: large enough to see with the naked eye.
Dr Franke-Arnold, who came up with the idea of using slow light in ruby to observe the photon drag, said: “We mainly wanted to demonstrate a fundamental optical principle, but this work has possible applications too.
“Images are information and the ability to store their intensity and phase is an important step to the optical storage and processing of quantum information, potentially achieving what no classical computer can ever match.
“The option to rotate an image by a set arbitrary angle presents a new way to code information, a possibility not accessed by any image coding protocol so far.”
Cei doi judecatori de la Inalta Curte din Londra responsabili de acest dosar au respins argumentele apararii potrivit carora cererea de extradare a australianului in varsta de 40 de ani este "injusta si contrara legii".
Julian Assange, suspectat in Suedia de viol si agresiune sexuala, a fost arestat in decembrie in Marea Britanie.
O prima instanta britanica a aprobat, in februarie, extradarea lui Assange, insa avocatii acestuia au declansat o procedura complexa de apel.
Fondatorul WikiLeaks, consemnat la domiciliu in Marea Britanie in asteptarea deciziei judecatoresti, locuieste la conacul unui prieten, nu departe de Londra.
Site-ul WikiLeaks a inceput sa publice in noiembrie 2010 mii de telegrame diplomatice americane, site-ul si fondatorul sau atragand critici dure din partea administratiei de la Washington.
Într-o biografie neautorizata publicata in septembrie, Julian Assange dezminte inca o data acuzatiile de viol formulate in Suedia, denuntand o manipulare politica. "Aceste doua femei au avut cu mine relatii sexuale deplin consimtite", afirma el.
All'inizio, due anni fa, c'era solo Cagliari, poi si è aggiunto Calenzano in provincia di Firenze, seguito da Genova, Castelfranco Emilia (Mo), Civita Castellana, Napoli, Torino e, più recentemente, Padova, Casalecchio di Reno (Bo), Castel del Piano in provincia di Grosseto. La lista dei comuni che ha istituito un registro del testamento biologico si allunga sempre più: ora se ne contano ottanta e hanno deciso di unirsi nella "Lega degli enti locali per il registro delle dichiarazioni anticipate di trattamento".
L'Associazione Luca Coscioni, promotrice della campagna iniziata nel 2009 dopo la morte di Eluana Englaro, può ritenersi soddisfatta. La mappa dell'Italia, consultabile on-line, è affollata di bandierine verdi che indicano i piccoli o grandi centri dove è possibile depositare le proprie volontà sul fine vita. Tra questi manca proprio Lecco, paese natale di Eluana Englaro, che ha rimandato al mittente con 28 voti contrari, 7 favorevoli e 4 astenuti, la proposta dell'istituzione del registro per le volontà anticipate di trattamento.
Tra gli obiettivi della neonata associazione di comuni vi è quello di "tutelare il diritto all'autodeterminazione dei cittadini anche attraverso gli adeguati strumenti giudiziari e ad individuare i principi giuridici che permettono alle amministrazioni locali di intervenire, nonostante controversie interpretative anche da parte ministeriale". Il documento della Lega dei comuni si riferisce a una circolare del 2010, firmata dai ministri della Salute Ferruccio Fazio, del Welfare Maurizio Sacconi e degli Interni Roberto Maroni, che liquidava l'iniziativa dei comuni come priva di "qualunque efficacia giuridica".
L'ANCI (Associazione Nazionale Comuni Italiani), da parte sua , ha sempre difeso il valore legale dei registri. Ma, in questo momento, la questione passa forse in secondo piano: la campagna dell'Associazione Luca Coscioni, così come le altre iniziative parallele (il videotestamento, la petizione al parlamento su testamento biologico ed eutanasia) serve innanzitutto per affermare il dissenso al DDL Calabrò che è in attesa di venire licenziato dal Senato, dopo gli emendamenti introdotti alla Camera il 12 luglio scorso.
The study, which appears in Science, reveals a unique pattern of brain activity when false memories are formed – one that hints at a surprising connection between our social selves and memory.
The experiment, conducted by Prof. Yadin Dudai and research student Micah Edelson of the Institute's Neurobiology Department with Prof. Raymond Dolan and Dr. Tali Sharot of University College London, took place in four stages. In the first, volunteers watched a documentary film in small groups. Three days later, they returned to the lab individually to take a memory test, answering questions about the film. They were also asked how confident they were in their answers.
They were later invited back to the lab to retake the test while being scanned in a functional MRI (fMRI) that revealed their brain activity. This time, the subjects were also given a "lifeline": the supposed answers of the others in their film viewing group (along with social-media-style photos). Planted among these were false answers to questions the volunteers had previously answered correctly and confidently. The participants conformed to the group on these "planted" responses, giving incorrect answers nearly 70% of the time.
But were they simply conforming to perceived social demands, or had their memory of the film actually undergone a change? To find out, the researchers invited the subjects back to the lab to take the memory test once again, telling them that the answers they had previously been fed were not those of their fellow film watchers, but random computer generations. Some of the responses reverted back to the original, correct ones, but close to half remained erroneous, implying that the subjects were relying on false memories implanted in the earlier session.
An analysis of the fMRI data showed differences in brain activity between the persistent false memories and the temporary errors of social compliance. The most outstanding feature of the false memories was a strong co-activation and connectivity between two brain areas: the hippocampus and the amygdala. The hippocampus is known to play a role in long-term memory formation, while the amygdala, sometimes known as the emotion center of the brain, plays a role in social interaction. The scientists think that the amygdala may act as a gateway connecting the social and memory processing parts of our brain; its "stamp" may be needed for some types of memories, giving them approval to be uploaded to the memory banks. Thus social reinforcement could act on the amygdala to persuade our brains to replace a strong memory with a false one.
On Dec. 5, 2010, Cassini first detected the storm that has been raging ever since. It appears approximately 35 degrees north latitude of Saturn. Pictures from Cassini's imaging cameras show the storm wrapping around the entire planet covering approximately 2 billion square miles (4 billion square kilometers).
The storm is about 500 times larger than the biggest storm previously seen by Cassini during several months from 2009 to 2010. Scientists studied the sounds of the new storm's lightning strikes and analyzed images taken between December 2010 and February 2011. Data from Cassini's radio and plasma wave science instrument showed the lightning flash rate as much as 10 times more frequent than during other storms monitored since Cassini's arrival to Saturn in 2004. The data appear in a paper published this week in the journal Nature.
"Cassini shows us that Saturn is bipolar," said Andrew Ingersoll, an author of the study and a Cassini imaging team member at the California Institute of Technology in Pasadena, Calif. "Saturn is not like Earth and Jupiter, where storms are fairly frequent. Weather on Saturn appears to hum along placidly for years and then erupt violently. I'm excited we saw weather so spectacular on our watch."
At its most intense, the storm generated more than 10 lightning flashes per second. Even with millisecond resolution, the spacecraft's radio and plasma wave instrument had difficulty separating individual signals during the most intense period. Scientists created a sound file from data obtained on March 15 at a slightly lower intensity period.
Cassini has detected 10 lightning storms on Saturn since the spacecraft entered the planet's orbit and its southern hemisphere was experiencing summer, with full solar illumination not shadowed by the rings. Those storms rolled through an area in the southern hemisphere dubbed "Storm Alley." But the sun's illumination on the hemispheres flipped around August 2009, when the northern hemisphere began experiencing spring.
"This storm is thrilling because it shows how shifting seasons and solar illumination can dramatically stir up the weather on Saturn," said Georg Fischer, the paper's lead author and a radio and plasma wave science team member at the Austrian Academy of Sciences in Graz. "We have been observing storms on Saturn for almost seven years, so tracking a storm so different from the others has put us at the edge of our seats."
The storm's results are the first activities of a new "Saturn Storm Watch" campaign. During this effort, Cassini looks at likely storm locations on Saturn in between its scheduled observations. On the same day that the radio and plasma wave instrument detected the first lightning, Cassini's cameras happened to be pointed at the right location as part of the campaign and captured an image of a small, bright cloud. Because analysis on that image was not completed immediately, Fischer sent out a notice to the worldwide amateur astronomy community to collect more images. A flood of amateur images helped scientists track the storm as it grew rapidly, wrapping around the planet by late January 2011.
The new details about this storm complement atmospheric disturbances described recently by scientists using Cassini's composite infrared spectrometer and the European Southern Observatory's Very Large Telescope. The storm is the biggest observed by spacecraft orbiting or flying by Saturn. NASA's Hubble Space Telescope captured images in 1990 of an equally large storm.
The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. NASA's Jet Propulsion Laboratory in Pasadena manages the mission for the agency's Science Mission Directorate in Washington. The radio and plasma wave science team is based at the University of Iowa, Iowa City, where the instrument was built. The imaging team is based at the Space Science Institute in Boulder, Colo. JPL is a division of the California Institute of Technology, Pasadena.
A set of glasses packed with technology normally seen in smartphones and games consoles is the main draw at one of the featured stands at this year’s Royal Society Summer Science Exhibition.
But the exhibit isn’t about the latest gadget must-have, it’s all about aiding those with poor vision and giving them greater independence.
‘We want to be able to enhance vision in those who’ve lost it or who have little left or almost none,’ explains Dr Stephen Hicks of the Department of Clinical Neurology at Oxford University. ‘The glasses should allow people to be more independent – finding their own directions and signposts, and spotting warning signals,’ he says.
Technology developed for mobile phones and computer gaming – such as video cameras, position detectors, face recognition and tracking software, and depth sensors – is now readily and cheaply available. So Oxford researchers have been looking at ways that this technology can be combined into a normal-looking pair of glasses to help those who might have just a small area of vision left, have cloudy or blurry vision, or can’t process detailed images.
The glasses should be appropriate for common types of visual impairment such as age-related macular degeneration and diabetic retinopathy. NHS Choices estimates around 30% of people who are over 75 have early signs of age-related macular degeneration, and about 7% have more advanced forms.
‘The types of poor vision we are talking about are where you might be able to see your own hand moving in front of you, but you can’t define the fingers,’ explains Stephen.
The glasses have video cameras mounted at the corners to capture what the wearer is looking at, while a display of tiny lights embedded in the see-through lenses of the glasses feed back extra information about objects, people or obstacles in view.
In between, a smartphone-type computer running in your pocket recognises objects in the video image or tracks where a person is, driving the lights in the display in real time.
The extra information the glasses display about their surroundings should allow people to navigate round a room, pick out the most relevant things and locate objects placed nearby.
‘The glasses must look discrete, allow eye contact between people and present a simplified image to people with poor vision, to help them maintain independence in life,’ says Stephen. These guiding principles are important for coming up with an aid that is acceptable for people to wear in public, with eye contact being so important in social relationships, he explains.
The see-through display means other people can see you, while different light colours might allow different types of information to be fed back to the wearer, Stephen says. You could have different colours for people, or important objects, and brightness could tell you how near things were.
Stephen even suggests it may be possible for the technology to read back newspaper headlines. He says something called optical character recognition is coming on, so it possible to foresee a computer distinguishing headlines from a video image then have these read back to the wearer through earphones coming with the glasses. A whole stream of such ideas and uses are possible, he suggests. There are barcode readers in some mobile phones that download the prices of products; such barcode and price tag readers could also be useful additions to the glasses.
Stephen believes these hi-tech glasses can be realised for similar costs as smartphones – around £500. For comparison, a guide dog costs around £25-30,000 to train, he estimates.
He adds that people will have to get used to the extra information relayed on the glasses’ display, but that it might be similar to physiotherapy – the glasses will need to be tailored for individuals, their vision and their needs, and it will take a bit of time and practise to start seeing the benefits.
The exhibit at the Royal Society will take visitors through how the technology will work. ‘The primary aim is to simulate the experience of a visual prosthetic to give people an idea of what can be seen and how it might look,’ Stephen says.
A giant screen with video images of the exhibition floor itself will show people-tracking and depth perception at work. Another screen will invite visitors to see how good they are at navigating with this information. A small display added to the lenses of ski goggles should give people sufficient information to find their way round a set of tasks. An early prototype of a transparent LED array for the eventual glasses will also be on display.
All of this is very much at an early stage. The group is still assembling prototypes of their glasses. But as well as being one of the featured stands at the Royal Society’s exhibition, they have funding from the National Institute of Health Research to do a year-long feasibility study and plan to try out early systems with a few people in their own homes later this year.
Source: PhysOrg - Resarch provided by Oxford University
Although this scenario is still several decades away, researchers have been making significant progress in developing early types of biomolecular computers.
In a recent study published in Nano Letters, Computer Science Professor Ehud Shapiro and coauthors from the Weizmann Institute of Science in Rehovot, Israel, have developed a biomolecular computer that can autonomously sense many different types of molecules simultaneously. In the future, this sensing ability could be integrated with a vast biomedical knowledge of diseases to enable computers to decide which drugs to release.
“We envision nanometer-sized computing devices (made of biomolecules) to roam our bodies in search of diseases in their early stage,” coauthor Binyamin Gil from the Weizmann Institute of Science told PhysOrg.com. “These devices would have the ability to sense disease indicators, diagnose the disease, and treat it by administering or activating a therapeutic biomolecule. They could be delivered to the bloodstream or operate inside cells of a specific organ or tissue and be given as a preventive care.”
A simple scheme of how a biomolecular computer works. Image credit: Gil, et al. ©2011 American Chemical Society
The development builds on the researchers’ previous demonstration of a biomolecular computer that consists of a two-state system made of biological components (DNA and a restriction enzyme). The computer, which operates in vitro, starts from the Yes state. In each computation step, the computer checks one disease indicator. If all of the indicators for the tested disease are present, the computation ends in the Yes state, namely it makes a positive diagnosis; if at least one disease indicator is not detected, it ends in the No state.
Previously, Shapiro's group showed that this biomolecular computer could detect disease indicators from mRNA expression levels and mutations. In the current study, the researchers have expanded the computer’s ability to also detect disease indicators from miRNAs, proteins, and small molecules such as ATP. At the same time, the computer’s detection method is simpler than before, requiring fewer components and fewer interactions with the disease indicators.
As the researchers explain, sensing a combination of several disease indicators is much more useful than sensing just one, since it allows for better accuracy and greater sensitivity to differences between diseases. For example, they note that in the case of thyroid cancer, the presence of the protein thyroglobulin and the hormone calcitonin can enable a much more reliable diagnosis than if only one of these disease indicators was detected.
Although the ability to detect several disease indicators marks an important step toward in vivo biomolecular computers and programmable drugs, there are still many obstacles that researchers must overcome in the process.
“The biggest challenge is operating such devices in living surrounding like the blood stream or cell's cytoplasm,” Gil said. “Currently we are developing devices that rely on simpler machinery (e.g. no restriction enzyme) or on the cell's own machinery.”
Mike Scharf, the O. Wayne Rollins/Orkin Chair in Molecular Physiology and Urban Entomology, said his laboratory has discovered a cocktail of enzymes from the guts of termites that may be better at getting around the barriers that inhibit fuel production from woody biomass. The Scharf Laboratory found that enzymes in termite guts are instrumental in the insects' ability to break down the wood they eat.
The findings, published in the early online version of the journal PLoS One, are the first to measure the sugar output from enzymes created by the termites themselves and the output from symbionts, small protozoa that live in termite guts and aid in digestion of woody material.
"For the most part, people have overlooked the host termite as a source of enzymes that could be used in the production of biofuels. For a long time it was thought that the symbionts were solely responsible for digestion," Scharf said. "Certainly the symbionts do a lot, but what we've shown is that the host produces enzymes that work in synergy with the enzymes produced by those symbionts. When you combine the functions of the host enzymes with the symbionts, it's like one plus one equals four."
Scharf and his research partners separated the termite guts, testing portions that did and did not contain symbionts on sawdust to measure the sugars created.
Once the enzymes were identified, Scharf and his team worked with Chesapeake Perl, a protein production company in Maryland, to create synthetic versions. The genes responsible for creating the enzymes were inserted into a virus and fed to caterpillars, which then produce large amounts of the enzymes. Tests showed that the synthetic versions of the host termite enzymes also were very effective at releasing sugar from the biomass.
They found that the three synthetic enzymes function on different parts of the biomass.
Two enzymes are responsible for the release of glucose and pentose, two different sugars. The other enzyme breaks down lignin, the rigid compound that makes up plant cell walls.
Lignin is one of the most significant barriers that blocks the access to sugars contained in biomass. Scharf said it's possible that the enzymes derived from termites and their symbionts, as well as synthetic versions, could be more effective at removing that lignin barrier.
Sugars from plant material are essential to creating biofuels. Those sugars are fermented to make products such as ethanol.
"We've found a cocktail of enzymes that create sugars from wood," Scharf said. "We were also able to see for the first time that the host and the symbionts can synergistically produce these sugars."
Next, Scharf said his laboratory and collaborators would work on identifying the symbiont enzymes that could be combined with termite enzymes to release the greatest amount of sugars from woody material. Combining those enzymes would increase the amount of biofuel that should be available from biomass.
The team at Exeter University used ‘phase-change alloys’ that move from an amorphous to fully crystallised state when subject to a current or light pulse.
‘What we are doing is trying to build electronic systems that mimic, in a simple way, the functionality of the basic building blocks of mammalian brains — namely neurons and synapses,’ project lead Prof David Wright of Exeter told The Engineer.
In conventional computers memory and processing units are physically separate, and data has to be continually shunted between the two, creating ‘bottlenecks’.
‘This slows everything down and wastes a lot of power and is the main reason chip manufacturers have moved to multi-core processors,’ Wright said.
The team turned to neurons for inspiration, noting that they make no real distinction between memory and computation. Looking for possible artificial substitutes the researchers came across so-called ‘phase-change materials’ that flip between amorphous and crystal states, in doing so inducing an electrical conductivity difference of up to five orders of magnitude and a large refractive index change.
Using laser pulses to induce the phase changes in germanium-antimony-tellurium (GeSbTe) and silver-indium-antimony-tellurium (AgInSbTe), the team was able to perform basic arithmetic and data storage.
‘A very simple model of a neuron is known as the “integrate and fire” model in which the neuron integrates, or accumulates, excitations applied to its input and fires a pulse along its output after a certain threshold has been passed.
‘We’ve shown that phase-change materials have a natural accumulation and threshold property, which makes them a good candidate for simple implementation of a hardware neuron,’ Wright said.
The upshot of the work is that these phase-change components could potentially be connected in networks via structures akin to synapses — potentially opening up an entirely novel way of computing.
‘The strength of these synaptic connections is altered by learning and experience — a common phrase to describe this is “neurons that fire together, wire together”.
‘We think that phase-change devices could also be used to make synapses — since the electrical resistance, or optical reflectivity, of phase-change materials depends on their excitation history,’ Wright said.
Indeed, shortly after publication of the Exeter work, a team from Stanford University in the US headed by Prof Philip Wong demonstrated just that, creating a nanoscale device with interconnected phase-change components.
Source: The Engineer
Taking inspiration from floating seeds, scientists from the Biomimetics-Innovation-Centre (B-I-C) in Germany have developed a promising new anti-fouling surface that is toxin-free.
The new surface is based on a seed from a species of palm tree that is dispersed by ocean currents. Suspecting that certain seeds may have specialized surfaces that gave them the ability to remain free of fouling to allow them to disperse further, the researchers floated seeds from 50 species in the North Sea for 12 weeks. At the end of the 12-week period, the seeds of 12 species showed no fouling at all.
"We then began by examining the micro-structure of the seeds' surfaces, to see if we could translate them into an artificial surface. The seeds we chose to mimic had a hairy-like structure," says Katrin Mühlenbruch, a PhD researcher at BIC. "This structure might be especially good at preventing fouling because the fibers constantly move, preventing marine organisms from finding a place to settle."
To create an artificial surface similar to the seeds, the researchers used a silicone base with fibers covering the surface. The new surface is currently being trialed by floating it in the sea. Ms. Mühlenbruch says that while the initial results are "quite good," there is still a long way to go.
Following on from the examination of the structure of the seeds' surface, the B-I-C researchers also plan to analyze the chemical composition of the seeds' surface to find out whether this adds to their anti-fouling properties.
"Our aim is to provide a new toxin-free and bio-inspired ship coating," says Ms. Mühlenbruch. "This would prevent environmental damage while allowing ships to operate efficiently."
Source: GizMag - via ZeitNews.org