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The expectations people have about how others will behave play a large role in determining whether people cooperate with each other or not. And moreover that very first expectation, or impression, is hard to change. "This is particularly true when the impression is a negative one," says Michael Kurschilgen from the Max Planck Institute for Research on Collective Goods in Bonn, summarising the key findings of a study in which he and his colleagues Christoph Engel and Sebastian Kube examined the results of so-called public good games. One's own expectation thereby becomes a self-fulfilling prophecy: those who expect people to act selfishly, actually experience uncooperative behavior from others more often.

In previous studies, other researchers had successfully put participants in Bonn and London into a social dilemma with such games, which are very popular in experimental economics. Engel, Kube and Kurschilgen used them as a template for their study, which focuses on an aspect that ought to be of interest to social policymakers and town planners too. "We wanted to find out whether the 'broken windows' theory held true in the lab as well," explained Michael Kurschilgen.

According to this theory, minor details, like broken windows in abandoned buildings or rubbish on the streets, can give rise to desolate conditions like the utter neglect of a district. "Such signs of neglect give people the impression that social standards do not apply there," says Kurschilgen, explaining the idea behind the theory, which was the motivation behind New York mayor Rudy Giuliani's decision to embark on the zero-tolerance strategy he employed to clean up the city in the 1990s.

In their study, the three MPI scientists tested the theory in a scientific experiment. Using the kind of public good games that are often applied in the field of experimental economics, their aim was to find out the extent to which first impressions determine how people will behave, and the extent to which this can be influenced by selective information. The games are set up around the classic dilemma of self-interest and socially minded behaviour: each member of a group of four players is given the sum of 20 tokens They can either keep these for themselves or invest them in a community project. Each player receives 0.4 tokens in return for each tokens they invest in the community project. If all four group members invest their 20 tokens, each one of them receives 32 tokens, in other words 12 tokens more than if they all keep the money for themselves. But if only three of them invest their money in the community, the selfish fourth player gets 44 tokens.

So even the free rider profits from the other players' investment in the community fund. "The public good game thus creates a social dilemma," explains the economist. That's because it would be best for the community if everybody invested in the collective. However, on an individual level the free rider gets the best out of it. They ultimately receive the bonus without having made the investment.

Surprisingly, there are significant differences between Bonn and London in the willingness to invest in the common good. Londoners invested a mere 43 per cent, on average, in the common good. In Bonn, on the other hand, the figure was 82 per cent. "This is probably down to differing expectations of what constitutes normal behaviour," postulates Kurschilgen. Individuals who assume that the others will act selfishly too are hardly likely to commit altruistic deeds themselves. "From that point of view, Londoners have a more pessimistic view of man than do the participants in Bonn," he concludes in respect of the Brits' reticence. Consequently, whether a person decides to behave cooperatively or not depends strongly on how that person thinks the other players will behave.

In their series of experiments, Engel, Kube and Kurschilgen told their newly recruited players from Bonn the results of the London study. The players in the new round of games evidently reacted very negatively to the information that few of the players in the previous experiments in London had exhibited cooperative behaviour. Unlike the virtuous people of Bonn from the previous rounds, they showed far fewer pretensions of being good citizens: instead of investing more than 80 per cent in the common good, the participants in these experiments contributed just 51 per cent, on average. Therefore, the negative information was enough to revise the previously positive image held by the Bonn residents. This model did not really work the other way around – good examples did not make bad teammates into goody two-shoes.

"Our findings demonstrate that the core of the 'broken windows' theory does actually hold true. Faced with a social dilemma, people are guided to a very great extent by their original expectations of what other people will do, but they are also particularly sensitive to negative impressions," says Kurschilgen, summing up the observations.

Given this conclusion, it is clear to him that every cent spent on maintaining residential districts does more than just make the neighbourhood look prettier – it also represents a sound investment against crime.

More information: Engel C., et al. Can we manage first impressions in cooperation problems? An experimental study on “Broken (and Fixed) Windows," Preprints of the Max Planck Institute for Research on Collective Goods, 2011/05

Source: Physorg.com

 

Few groups are as vilified as atheists. They tend to be viewed as party poopers bent on dismantling the cherished beliefs of "people of faith." While that element of the atheist community does exist--as is verified by the endless websites and books dedicated solely to tackling the logical flaws in religious claims--the reality is that the growing movement of outspoken atheists have far more on offer than winning arguments with people who believe in a god. Atheism is also a burgeoning social justice movement that looks to tear down the social structures that have perpetuated injustice for millennia.

Just as feminists take on the patriarchy, peace activists fight the ideology of war, civil rights activists and abolitionists dismantle the traditions of racism, and humanists erode authoritarian hierarchies, atheists are standing up and saying that the human race needs to evolve beyond religion. And it’s this social justice model that’s invigorating a new generation of atheists to move beyond just quietly disbelieving into openly challenging religious irrationality.  

Blame the religious right for pushing atheists in this new, more political direction. The past couple of decades have seen an explosion in fundamentalist energy and power. The immediacy of the fundamentalist threat to science, education and human rights starkly demonstrates that the problem of religion extends beyond its inherent irrationality. Many atheists who find endless proofs against god tiring find themselves drawn to organized atheism as a weapon against this religious threat to liberty and free inquiry.  

Even though many liberal religious people exist, at its base, the argument between god believers and atheists is roughly the same argument as that between conservatives and progressives. Liberalism is rooted in the humanist tradition, which demands that society and government prioritize human needs and desires, using the tools of rationality and evidence toward those goals. Conservativism values hierarchy and tradition and rejects evidence-based reasoning in favor of arguments from authority. The imaginary god provides the perfect conservative authority; a completely evidence-free, ultimate authority that can make pronouncements believers are expected to simply submit to. Submission and faith are built into even the most liberal Christian traditions, in direct contrast to the humanist philosophy of questioning and demanding evidence.  

Humanism has given birth to progressivism by opening up space to question some of the oldest prejudices: the belief that men are better than women, that gays are “unnatural,” that different skin colors or ethnicities automatically means different roles and mental abilities, that people are wealthier because they’re more deserving, that kings rule by divine right. When you start asking hard questions of these other beliefs, you often discover that the rationale for all of them tends to circle back toward “God said so.” By questioning this most fundamental of beliefs, that there is a god and he’s making the rules, we can call into question the illogic of all these other beliefs.  

Despite the atheist movement's emphasis on proofs against supernatural claims, many, if not most people who join the atheist movement came to atheism because they were questioning other beliefs and traditions. Certainly this was my path. I never really “believed” in god growing up, but I didn’t identify as an atheist either. I just didn’t think about the issue much. Feminism compelled me to start looking harder at religious arguments against women’s equality, and in doing so, I realized that without a forceful response to religious irrationality, feminist progress would be stymied. And so I started engaging logical arguments supporting what seemed self-evident to me, that there couldn’t be any gods, and therefore no supernatural beings whose authority can be invoked when anti-feminists lack real-world evidence for their claims. 

I’m far from alone in this. Last November, when I spoke on feminism and atheism at the annual atheist/skeptical conference in Springfield, MO, I met dozens of young and eager atheists. A solid majority of them had come to the movement after feeling oppressed by religion. Some people had grown up in fundamentalist communities whose backward beliefs about gender and sexuality drove them to start asking questions, while others had dealt with conflicts between their own love of science and the claims of religion. Still others had mostly dealt with moderate or even liberal churches, but were disappointed by the way even the most liberal religions discourage hard questions. In other words, these people began from a position of valuing progressive ideals, and those values led them to the atheist community.  

Online atheist communities find their secular values make a sort of “pure” atheism that’s largely apolitical and impossible to maintain. The popular atheist/skeptic website Skepchick started mainly to highlight women who support atheism, rational inquiry and science, but over time the site made a turn toward the explicitly feminist, in part because of the constant drumbeat of fact-free claims about women’s roles being made by religious figures in the media. Links between atheism and progressivism have also been easy to make for proponents of gay rights and sexual liberation, as demonstrated by recent research showing that those who lose their faith and embrace atheism report an improved sex life.

But atheist progressives shouldn’t feel limited to arguments about gender and sexuality when linking their atheism to broader issues. There’s plenty of room for an atheist environmentalism -- since there’s no afterlife, we should prioritize taking care of the one world we do have. Or an atheist economic liberalism -- since there’s no such thing as “providence,” it’s our responsibility to care for the poor and the needy.

Atheists are only by limited by our imaginations in seeking ways to make our lack of faith as central to our view of a just world as religious people make their faith central to their worldviews.

Source: alternet.org - Author: Amanda Marcotte (she co-writes the blog Pandagon. She is the author of It's a Jungle Out There: The Feminist Survival Guide to Politically Inhospitable Environments.)

 

It is said that wisdom comes with age, but with openness and skepticism, the key principles of the scientific method, we don't need decades of trial and error to sort out which of our convictions may be improbable. The questions is not whether our beliefs are right or wrong, but whether or not being emotionally attached to them is more or less likely to benefit us. There is no such thing of free choice while being emotionally attached to a belief system. The moment we are self-aware enough to realize this, we can truly work together to figure out the real odds of what will benefit us the most.


Professor of Communication Studies Corey Anton at Grand Valley State University reviews AToE:
http://www.youtube.com/watch?v=YK9-KQZbnHQ
Rocket Engineer Evie Marom's review: 
http://bit.ly/gCvM8e

1080P Torrent link: http://thepiratebay.org/torrent/6125081 / Direct download:http://wioym.net/athene/atoe.mp4
(much higher quality than YouTube's 1080P)

http://www.Athenism.net
Twitter: http://www.twitter.com/Athenist
Facebook: http://www.facebook.com/pages/Athenism/126607000711913
Reese on Twitter: http://www.twitter.com/Reese015

Full soundtrack coming soon at
http://www.ProfessorKliq.com
(who did the amazing original soundtrack)

Full HD torrent coming soon.


Related links that can help in understanding Athene's Theory of Everything:

(Neuroscience related:)
YouTube - Part 4 - Phantoms In The Brain (Episode 1)
http://www.youtube.com/watch?v=_1RPkp7rdnw#t=2m30s
YouTube - Part 5 - Phantoms In The Brain (Episode 1)
http://www.youtube.com/watch?v=F0R0OCurkLM#t=3m36s
Where is consciousness?
http://discovermagazine.com/video/unlocking-secrets-power-of-brain-nsf
Joseph M. Carver, Ph.D. - Norepinephrine: From Arousal to Panic 
http://www.enotalone.com/article/4117.html
Dharol Tankersley, C Jill Stowe, and Scott A Huettel - Brain Scan Predicts Difference Between Altruistic And Selfish People 
http://www.medicalnewstoday.com/articles/61312.php
New Scientist - Empathetic mirror neurons found in humans at last
http://www.newscientist.com/article/mg20627565.600-empathetic-mirror-neurons-...
Dr. Christopher Reist - Psychiatry And The Brain
http://www.videojug.com/interview/psychiatry-and-the-brain
John McManamy - Dopamine - Serotonin's Secret Weapon 
http://www.mcmanweb.com/dopamine.html
Invalidation 
http://eqi.org/invalid.htm
YouTube - The Neuroscience of Emotions 
http://www.youtube.com/watch?v=tShDYA3NFVs
How Our Brains Make Memories
http://www.smithsonianmag.com/science-nature/How-Our-Brains-Make-Memories.htm...
Alpha, beta, gamma - The language of brainwaves - life - 12 July 2010 - New Scientist
http://www.newscientist.com/article/mg20727680.200-alpha-beta-gamma-the-langu...
TSN: Take the Neuron Express for a brief tour of consciousness
http://thesciencenetwork.org/programs/the-science-studio/take-the-neuron-expr...
LeDouxlab Web-AudioFearful_Brains
http://www.cns.nyu.edu/ledoux/slide_show/Audio_show_Fearful_Brains.htm
Joseph LeDoux Can Memories Be Erased
http://www.huffingtonpost.com/joseph-ledoux/can-memories-be-erased_b_303519.html
Zócalo Public Square :: Full Video
http://zocalopublicsquare.org/full_video.php?event_id=163
When in doubt, shout -- why shaking someone's beliefs turns them into stronger advocates | Not Exactly Rocket Science | Discover Magazine
http://blogs.discovermagazine.com/notrocketscience/2010/10/19/when-in-doubt-s...
The Brain: How The Brain Rewires Itself - TIME
http://www.time.com/time/magazine/article/0,9171,1580438,00.html

(physics related:)
The Feynman Double Slit 
http://www.upscale.utoronto.ca/PVB/Harrison/DoubleSlit/DoubleSlit.html
YouTube - Lecture - 1 Introduction to Quantum Physics;Heisenberg''s uncertainty principle 
http://www.youtube.com/watch?v=TcmGYe39XG0&feature=PlayList&p=0F530F3...
The Wave Nature of Matter 
http://www.colorado.edu/physics/2000/quantumzone/debroglie.html
The Particle Adventure - What holds it together - The unseen effect
http://www.particleadventure.org/unseen.html
Unsolved problems in physics
http://www.cpepweb.org/images/chart_details/Unsolved.jpg
Press Pass - Press Release - CDF B_s 
http://www.fnal.gov/pub/presspass/press_releases/CDF_meson.html
Big Bang Timeline
http://map.gsfc.nasa.gov/media/060915/060915_CMB_Timeline300.jpg
Einstein's time dilation apparent when obeying the speed limit 
http://arstechnica.com/science/news/2010/09/einsteins-relativity-measured-in-...
The Ultimate Field Guide to Subatomic Particles 
http://io9.com/5639192/


For press inquiries:
Reese Leysen, CEO ipowerproject.com
e-mail: press@ipowerproject.com
phone: +32 (0) 496 46 97 18

 

Given sufficient forward speed, a bicycle pushed sideways, will not fall over. Scientists have been trying to find a conclusive explanation for this remarkable characteristic for over a century. This week, researchers at TU Delft have thrown new light on the question in a publication in Science.

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Staying stable

The research at TU Delft, in collaboration with scientists from Cornell University (USA), centred on the following intriguing question: why is a bicycle self stable, above a certain speed? You add speed to a bike and can then give it a sideways push without it falling over.

Rotating wheels

Scientists have long been poring over this complicated question, even from as far back as the nineteenth century. Until recently, the consensus within the scientific community was that the stability was very closely related to two factors. First, the rotating wheels of the bicycle were supposed to provide stability through gyroscopic effects. Secondly, it was thought that the ‘trail’ played an important part. Trail is the distance by which the contact point of the front wheel trails behind the steering axis.

Predicting

The publication by TU Delft in Science puts paid to this old notion once and for all. 'We have known for years that the generally accepted explanation for the stability of the bicycle was too simple,' says researcher Dr Arend Schwab of the 3mE faculty at TU Delft. 'Gyroscopic effects and trail do help, but are not essential for stability.' Dr Schwab and a number of colleagues brought out a publication several years ago on the theory behind the stability of the bicycle (in 2007 in Proceedings of the Royal Society, doi:10.1098/rspa.2007.1857). A mathematical model with around 25 physical parameters was developed at the time, which appeared to be able to predict very accurately whether, and at what speeds, a particular design of bicycle would be stable.

The Experiment

'In our publication in Science we have now shown not only theoretically but also by means of experiment  that our insights are correct.' Together with PhD student Jodi Kooijman, Schwab designed and constructed a bicycle with which it could be shown, in an experiment, that both gyroscopic effects and trail are not necessary for a bicycle to remain stable by itself above a certain speed.
This is the so-called Two Mass Skate bicycle. It has small and counter rotating wheels, which means there is no gyroscopic effect to speak of, and a small negative trail (in other words, where the point of contact of the front wheel is marginally in front of the steering axis). And yet the bicycle remains stable.

See the experiment Here

Giving up

'It was not easy,' explains PhD student Jodi Kooijman, who carried out most of the experimental work. 'The first prototype did not work, and we had almost given up hope after a number of iteration attempts, when we suddenly found ourselves able to show the stability. But of course everything has to fall into place. You have to deal with the ground surface, for example, which has to have exactly the right roughness and stiffness. In Sporthal II of TU Delft we found all the right conditions.'

Steering

So the theory has now been proven by experiment. But has the experimental work led to the emergence of new theoretical insights? Dr Schwab answers, 'We have demonstrated that the mass distribution is also important for stability, especially the location of the centre of mass of the bicycle's steering mechanism.' For a bicycle to be stable, the steering mechanism has to be unstable; if the bike falls, the steering should fall even more quickly.

Bicycle manufacturers

Are the theoretical insights of Schwab and his companions of any use to bicycle manufacturers? 'Certainly. Today’s bicycles are the result of a fairly long evolutionary process, and are therefore rather conservative. Essentially, there is nothing about the basic design of the bicycle that has changed since the end of the nineteenth century. Manufacturers can use our model to make directed modifications to the stability of their bicycles. That may be of particular interest for unusual designs, such as recumbent bicycles, folding bicycles and cargo bicycles.'

Source: 3mE TU Delft

More information

Title: A Bicycle Can Be Self-Stable Without Gyroscopic or Caster Effects.

Authors: J.D.G. Kooijman; A. L. Schwab (TU Delft), J.P. Meijaard (University of Twente), J.M. Papadopoulos (University of Wisconsin–Stout), A. Ruina (Cornell University)

Website Science publication, with extensive background material, photos and video: http://bicycle.tudelft.nl/stablebicycle/

Website Bicycle Dynamics research: http://bicycle.tudelft.nl/schwab/Bicycle/index.htm

 

Working with funding from Google, they hope to make computers understand what it’s like to pursue an outcome only to be disappointed. That, they think, could really help computers predict the future.

While software may never know what it’s like to roll out of bed with splitting headache and dress quietly in the dark, it can certainly measure the distance between a desired outcome and the actual outcome achieved. And by doing so computers could learn to minimize “regret,” which in this case is measured by that distance.

TAU computer scientists working on learning theory and other thorny computer intelligence issues think that by teaching computers to reduce regret, they would essentially be teaching them to evaluate all the relevant variables surrounding an outcome in advance. This would allow them to do things like more efficiently route Internet traffic, prioritize server resource requests, or predict when traffic to a site might spike and provide the necessary capacity beforehand. And they could do it all based on data coming to them in real-time.

Source: Popsci

 

By directly linking the motions of two physically separated atoms, the technique has the potential to simplify information processing in future quantum computers and simulations.

Described in a paper published Feb. 23 by Nature, the NIST experiments enticed two beryllium ions (electrically charged atoms) to take turns vibrating in an electromagnetic trap, exchanging units of energy, or quanta, that are a hallmark of quantum mechanics. As little as one quantum was traded back and forth in these exchanges, signifying that the ions are "coupled" or linked together. These ions also behave like objects in the larger, everyday world in that they are "harmonic oscillators" similar to pendulums and tuning forks, making repetitive, back-and-forth motions.

"First one ion is jiggling a little and the other is not moving at all; then the jiggling motion switches to the other ion. The smallest amount of energy you could possibly see is moving between the ions," explains first author Kenton Brown, a NIST post-doctoral researcher. "We can also tune the coupling, which affects how fast they exchange energy and to what degree. We can turn the interaction on and off."

The experiments were made possible by a novel, one-layer ion trap cooled to minus 269 C (minus 452 F) with a liquid helium bath. The ions, 40 micrometers apart, float above the surface of the trap. In contrast to a conventional two-layer trap, the surface trap features smaller electrodes and can position ions closer together, enabling stronger coupling. Chilling to cryogenic temperatures suppresses unwanted heat that can distort ion behavior.

The energy swapping demonstrations begin by cooling both ions with a laser to slow their motion. Then one ion is cooled further to a motionless state with two opposing ultraviolet laser beams. Next the coupling interaction is turned on by tuning the voltages of the trap electrodes. In separate experiments reported in Nature, NIST researchers measured the ions swapping energy at levels of several quanta every 155 microseconds and at the single quantum level somewhat less frequently, every 218 microseconds. Theoretically, the ions could swap energy indefinitely until the process is disrupted by heating. NIST scientists observed two round-trip exchanges at the single quantum level.

To detect and measure the ions' activity, NIST scientists apply an oscillating pulse to the trap at different frequencies while illuminating both ions with an ultraviolet laser and analyzing the scattered light. Each ion has its own characteristic vibration frequency; when excited, the motion reduces the amount of laser light absorbed. Dimming of the scattered light tells scientists an ion is vibrating at a particular pulse frequency.

To turn on the coupling interaction, scientists use electrode voltages to tune the frequencies of the two ions, nudging them closer together. The coupling is strongest when the frequencies are closest. The motions become linked due to the electrostatic interactions of the positively charged ions, which tend to repel each other. Coupling associates each ion with both characteristic frequencies.

The new experiments are similar to the same NIST research group's 2009 demonstration of entanglement -- a quantum phenomenon linking properties of separated particles -- in a mechanical system of two separated pairs of vibrating ions. However, the new experiments coupled the oscillators' motions more directly than before and, therefore, may simplify information processing. In this case the researchers observed quantum behavior but did not verify entanglement.

The new technique could be useful in a future quantum computer, which would use quantum systems such as ions to solve problems that are intractable today. For example, quantum computers could break today's most widely used data encryption codes. Direct coupling of ions in separate locations could simplify logic operations and help correct processing errors. The technique is also a feature of proposals for quantum simulations, which may help explain the mechanisms of complex quantum systems such as high-temperature superconductors.

In addition, the demonstration also suggests that similar interactions could be used to connect different types of quantum systems, such as a trapped ion and a particle of light (photon), to transfer information in a future quantum network. For example, a trapped ion could act as a "quantum transformer" between a superconducting quantum bit (qubit) and a qubit made of photons.

Source: Science Daily

 

Proton exchange membrane fuel cells, also known as polymer electrolyte membrane fuel cells (PEMFCs), offer a way to power future emission-free vehicles, by providing stationary and portable power sources. However, the high cost and low durability of platinum catalysts are two major challenges hindering their commercialization. Researchers from the University of Western Ontario, and General Motors Research and Development Center have now discovered a new catalyst, platinum nanostars, that could make fuel cells more cost-effective and stable. [S. H. Sun et al., Angew Chem Int Ed (2011) 50, 422].

 HRTEM image of a multiarmed single-crystal Pt nanostar

Pt is the most effective catalyst for fuel (usually hydrogen) oxidation at the anode and oxygen reduction reaction (ORR) at the cathode. The ORR is considerably slower than the oxidation of H2, and requires more catalyst. But Pt is expensive and relatively rare, and so has pushed up the price of fuel cells. At present, the most widely used cathode catalysts consist of fine particles of Pt supported on carbon black supports. In contrast to Pt nanoparticles, one-dimensional structures of Pt, such as nanowires, exhibit additional advantages associated with their anisotropy and unique structure.

Star-like single-crystal platinum nanostructures were produced, each with several nanowire arms with diameters of ~4 nm on carbon black. The carbon supported star-like Pt nanostructures (star-like PtNW/C) were synthesized in an environmentally friendly process, which does not require high temperatures, organic solvents, surfactants or complicated electrochemical deposition apparatus, by reducing a Pt precursor (H2PtCl6) with formic acid (HCOOH) in aqueous solution at room temperature.

The star-like PtNW/C showed greatly improved activity and durability compared to a state-of-the-art commercial catalyst made of Pt nanoparticles on carbon. More interestingly, the durability can be further improved by eliminating the carbon support.

The key reason this strategy works relies on the combination of a multi-armed network structure and the one-dimensional shape of the arms. This helps the activity and durability. In addition, the few surface defects and the preferential exposure of certain crystal facets further improves the activity. The increased activity and durability means that the amount of Pt needed on an electrode can be reduced, which could significantly lower the cost and increase the durability of PEMFCs.

Source: Materials Today

 
By Admin (from 29/06/2011 @ 11:00:36, in en - Science and Society, read 1690 times)

When Gutenberg developed the principles of modern book printing, books became available to the masses. Hoping to bring technology capable of mass production to the nanometer scale, Udo Bach and this team of scientists at Monash University and the Lawrence Berkeley National Laboratory have developed a nanoprinting process modeled on Gutenberg’s printing method. Their goal is the simple, inexpensive production of nanotechnological components for solar cells, biosensors, and other electronic systems. As the researchers report in the journal Angewandte Chemie, their "ink" consists of gold nanoparticles, and the specific bonding between DNA molecules ensures its transfer to the substrate.

Hot off the press: Nanoscale Gutenberg-style printing

Nanopatterns with extremely high resolution are not difficult to produce with today’s technology. However, the methods used so far are analogous those used to produce the hand-written books of the era before Gutenberg; they are too slow and work-intensive for commercial fabrication. “New nanoprinting techniques offer an interesting solution,” says Bach. Along with co-workers, he has developed a process that works with a reusable “printing plate”.

The printing plate is a silicon wafer—like those used for the production of computer chips—that has been coated with a photoresist and covered with a mask. The wafer is then exposed to an electron beam (electron beam lithography). In the areas exposed to the beam, the photoresist is removed, exposing the wafer for etching. The wafer is then coated with gold. When the photoresist layer is removed, the gold only sticks to the etched areas. Polyethylene glycol chains are then bound specifically to the gold through sulfur–hydrogen groups. The chains have positively charged amino groups at their ends. The completed printing plate is then dipped into the “ink”, a solution of gold nanoparticles coated with negatively charged DNA molecules. Electrostatic attraction causes the DNA to stick to the amino groups, binding the gold nanoparticles to the gold-patterned areas of the printing plate.

The “paper” is a silicon wafer coated with a whisper-thin gold film and a layer of DNA. These DNA strands are complementary to those on the gold nanoparticles, with which they pair up to form double strands. This type of bond is stronger than the electrostatic attraction between the DNA and the amino groups. When the “paper” is pressed onto the “printing plate” and then removed, the gold nanoparticles from the ink remain stuck to the “paper” in the desired pattern. The “printing plate” can be cleaned and reused multiple times. Says Bach: “Our results demonstrate that it is possible to produce affordable printed elements based on nanoparticles.”

Source: PhysOrg

 

To diversify the applications of superconductors that currently operate at chilly temperatures below 135 kelvin (K), scientists are searching for new classes of superconducting materials that will show this property at warmer temperatures. Now, a research team in Japan has synthesized a promising new class of superconductors1, made of Hg0.44ReO3, where an unusual motion of the mercury (Hg) atoms enhances superconducting properties at temperatures up to 7.7 K.

Mercury rising

The crystal structure of HgxReO3. The mercury (Hg) atoms are shown in blue, oxygen (O) in red and rhenium (Re) in brown. Credit: 2011 The American Physical Society

The Dutch physicist Heike Kamerlingh Onnes discovered superconductivity one hundred years ago, when he noticed that the electrical resistance of mercury dropped to zero suddenly at 4.2 K. Superconducting materials are now used routinely in magnetic resonance imaging scanners.

In classical superconductors such as mercury, superconductivity arises through the combined vibrations of the atoms in the crystal. This makes the crystal structure a key factor for the superconducting properties of a material. In the case of HgxReO3, the atomic structure consists of rhenium (Re) and oxygen (O) building blocks. In the empty spaces between them, the mercury atoms arrange in chains (Fig. 1). However, some of the available places along these chains lack mercury atoms, and the team’s work suggests that this leads to an arrangement of paired mercury atoms.

"These pairs move within the channel in an oscillatory motion known as rattling", explains team-member Ayako Yamamoto from the RIKEN Advanced Science Institute in Wako. The rattling vibrations provide a strong feedback for the electrons, and therefore reinforce superconductivity in the material. In comparison to a similar structure lacking mercury pairs, the superconducting temperature of Hg0.44ReO3 at 7.7 K is almost twice as high. "Despite remaining below the present record of 135 K for a superconductor, there is potential for improving operation temperatures", says Yamamoto. “The application of pressure increases the superconducting temperature to 11.1 K, and this could mean that for the right crystal structure further enhancement is possible.”

Yamamoto and her colleagues are now working to optimize the crystal structure further—for example, by replacing rhenium with other elements. A better understanding of the influence of the mercury atoms’ rattling motion may also provide better insight into the mechanism of superconductivity in such structures. “Mercury seems to be a magic element in superconductivity, not only for its role in Kamerlingh Onnes’ discovery, but also for the fact that mercury is part of the material with the highest known superconducting temperature, HgBa2Ca2Cu3Ox,” Yamamoto explains. "Once more, mercury is playing a key role for new superconductors," she says.

Source: PhysOrg

 
By Admin (from 25/06/2011 @ 08:00:45, in en - Science and Society, read 1578 times)

Technology using catalysts which make hydrogen from formic acid could eventually replace lithium batteries and power a host of mobile devices.

Edman Tsang of Oxford University’s Department of Chemistry and colleagues are developing new catalysts which can produce hydrogen at room temperature without the need for solvents or additives.

Their initial results, reported in a recent paper in Nature Nanotechnology, are promising and suggest that a hydrogen fuel cell in your pocket might not be that far away.

Putting a fuel cell 'in your pocket'

The core-shell particle (palladium atoms on a silver nanoparticle).

The new approach involves placing a single atomic layer of palladium atoms onto silver nanoparticles. ‘The structural and electronic effects from the underlying silver greatly enhance the catalytic properties of palladium, giving impressive activity for the conversion of formic acid to hydrogen and carbon dioxide at room temperature,’ Edman told us.

He explains that the storage and handling of organic liquids, such as formic acid, is much easier and safer than storing hydrogen. The catalysts would enable the production of hydrogen from liquid fuel stored in a disposable or recycled cartridge, creating miniature fuel cells to power everything from mobile phones to laptops.

Another advantage of the new technology is that the gas stream generated from the reaction is mainly composed of hydrogen and carbon dioxide but virtually free from catalyst-poisoning carbon monoxide; removing the need for clean-up processes and extending the life of the fuel cells.

The chemists have worked closely with George Smith, Paul Bagot and co-workers at Oxford University’s Department of Materials to characterise the catalysts using atom probe tomography. The underlying technology is the subject of a recent Isis Innovation patent application.

‘There are lots of hurdles before you can get a real device, but we are looking at the possibility of using this new technology to replace lithium battery technology with an alternative which has a longer lifespan and has less impact on the environment,’ explains Edman.

Source: PhysOrg

 
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