Archive for the ‘Science and Fiction’ Category

New material for nanoscale-computer chips

Thursday, August 20th, 2009
 

Researchers cross organic and non-organic nano wires like Mikado sticks and thereby make nanoscale prototype computer electronics. Image by Asmus Dohn.

Researchers cross organic and non-organic nano wires like Mikado sticks and thereby make nanoscale prototype computer electronics. Image by Asmus Dohn.

New data from Chinese-Danish collaboration shows that organic nanoscale wires could be an alternative to silicon in computer chips. The discovery has just been published in the respected scientific journal, Advanced Materials.

 

Nanochemists from the Chinese Academy of Sciences and the Nano-Science Center, Department of Chemistry have developed nanoscale electric contacts out of organic and inorganic nanowires. In the contact they have crossed the wires like Mikado sticks and coupled several contacts together in an electric circuit. In this way they have produced prototype computer electronics on the nanoscale.

Alternative to silicon computers

Today the foundation of our computers, mobile phones and other electronic apparatus is silicon transistors. A transistor is in principal an on- and off- contact and there are millions of tiny transistors on every computer chip. However, we are reaching the limit for how small we can make transistors out of silicon.

We already use various organic materials in, for example, flat screens, such as OLED (Organic Light Emitting Diode). The new results show how small and advanced devices made of organic materials can become. Thomas Bjørnholm, Director of the Nano-Science Center, Department of Chemistry at University of Copenhagen explains:

- “We have succeeded in placing several transistors consisting of nanowires together on a nano device. It is a first step towards realisation of future electronic circuitry based on organic materials – a possible substitute for today’s silicon-based technologies. This offers the possibility of making computers in different ways in the future.”

Danish-Chinese nanoelectronics

The researchers have used organic nanowires combined with the tin oxide nanowires in a so-called hybrid circuit. As in a Mikado game, the nanowires cross in a device consisting of 4-6 active transistor moieties. The devices have a low operational current, high mobility and good stability and that is essential in order for the material to be able to compete with silicon.

Professor Wenping Hu, Chinese Academy of Sciences is excited over the results:

- “This work is the first significant result of our collaboration with the researchers from the Nano-Science Center. It is a good starting point for our new Danish-Chinese research centre for molecular nano-electronics and it underlines the fact that we can complement each other and that together we can achieve exciting and important results.”

 

 

 

Source:

University of Copenhagen

Which Facial Features Our Brain Examines To Identify Faces?

Monday, July 20th, 2009

Facial FeaturesA study by the University of Barcelona (UB) has analysed which facial features our brain examines to identify faces. Our brain adapts in order to obtain the maximum amount of information possible from each face and according to the study the key data for identification come from, in the first place, the eyes and then the shape of the mouth and nose.

The objective of this study, undertaken by researcher Matthias S. Keil from the Basic Psychology Department of the UB and published in the prestigious US journal PLOS Computational Biology, was to ascertain which specific features the brain focuses on to identify a face. It has been known for years that the brain primarily uses low spatial frequencies to recognise faces. “Spatial frequencies” are, in a manner of speaking, the elements that make up any given image.

As Keil confirmed to SINC, “low frequencies pertain to low resolution, that is, small changes of intensity in an image. In contrast, high frequencies represent the details in an image. If we move away from an image, we perceive increasingly less details, that is, the high spatial frequency components, while low frequencies remain visible and are the last to disappear.”

As a result of the psychophysical research carried out prior to the publication of this study, it was known that the human brain was not interested in very high frequencies when identifying faces, despite such frequencies playing a significant role in, for example, determining a person’s age. “In order to identify a face in an image, the brain always processes information with the same low resolution, of about 30 by 30 pixels from ear to ear, ignoring distance and the original resolution of the image,” Keil says. “Until now, nobody had been able to explain this peculiar phenomenon and that was my starting point”.

What Matthias S. Keil did was to analyse a large number of faces, namely those belonging to 868 women and 868 men. “The idea was to find common statistical regularities in the images.” Keil used a model of the brain’s visual system, that is, “I looked at the images to certain extent like the brain does, but with one difference: I had no preferred resolution, but considered all spatial frequencies as equal. As a result of this analysis, I obtained a resolution that is optimum in terms of encoding, as well as the signal-to-noise ratio, and was also the same resolution observed in the psychophysical experiments”.

This result therefore suggests that faces are themselves responsible for our resolution preference. This led Keil to one of the brain’s properties: “The brain has adapted optimally to draw the most useful information from faces in order to identify them. My model also predicts this resolution if we take into account the eyes alone – ignoring the nose and the mouth – but also by considering the mouth or nose separately, albeit less reliable.”

Therefore, the brain extracts key information for facial identification primarily from the eyes, while the mouth and the nose are secondary, according to the study. According to Keil, if we take a photo of a friend as an example, one might think that every feature of the face is important to identify the person. However, numerous experiments have demonstrated that the brain prefers a coarse resolution, regardless of the distance between the face and the beholder. Until now, the reason for this was unclear. The analysis of the pictures of 868 men and 868 women in this study could help to explain this.

The results obtained by Kiel indicate that the most useful information is drawn from the images if they are around 30 by 30 pixels in size. “Furthermore, the pictures of the eyes provide the least ‘noisiest’ result, which means that they transmit more reliable information to the brain than the pictures of the mouth and the nose,” the researcher said. This suggests that the brain’s facial identification mechanisms are specialised in eyes.

This research complements a previous study published by Keil in PLoS ONE, which already advanced that artificial face identification systems obtain better results when they process small pictures of faces, which means that they could behave in this sense like humans.

Source: Plataforma SINC

The Werewolf`s Transformation

Tuesday, July 14th, 2009

The werewolfThe werewolf is a fascinating creature in human literature. It is the imaginative link between the raw, natural, animal world, and the modern civilized human. The werewolf is a sort of symbolic representation of the primal being that still exists, to some extent, in all of us. However in this case that inner nature gets out, and the person takes on the form of their hidden primal self.

The nature of the werewolf’s transformation is one which is defined by the type of creature they are. There are many different stories and myths pertaining to the werewolf. Ancient claims have them as humans possessed by demons, or animal spirits. In more modern tales they are also the result of genetic manipulation, disease, or chemical induction.

The change itself is an issue that has been difficult for writers, and especially for makers of movies. There is no real way to show a person completely changing into something else without it looking like a fake. Just morphing looks cartoonish, and having the person simply grow tufts of hair is usually inadequate for the effect.

Some modern stories tell of a person growing into the werewolf form. This can be through muscles suddenly bulging, hair popping out, teeth growing, and the like. In general this is the easiest and most believable way to demonstrate the change.

Another method has the person becoming transfigured in a relatively gruesome way. In this method the body grows out of itself, but it is much more dramatic and violent, and makes for a better horror story.

The werewolf is a powerful symbol of the primal instinct that is within us all. By seeking to understand its nature in literature and movies, we can better come to understand our own nature, and the soul of human beings.

10 Challenges of a Liberated Woman

Wednesday, June 11th, 2008
Liberated WomanThe mission of the EnlightenNext women is to pioneer a new stage of human culture through transforming themselves and their relationships. For culture to change, the core dynamics that define who we are and how we relate need to evolve. While women and men have become social equals by law, we are all still deeply conditioned by ancient survival patterns in which women are subordinate and compete with one another for male attention and protection. To create a new ground of human relationship, the EnlightenNext women have been working with their spiritual teacher Andrew Cohen for twelve years to develop a field of liberated, enlightened consciousness between them that transcends the separation of egoic conditioning, individually and collectively. It is a delicate, difficult, and thrilling endeavor. The women at EnlightenNext have identified ten challenges—and the ideals they point to—facing a woman who wants to create an enlightened future.
1. Holding an Evolutionary Perspective
She strives to live in the knowledge that the creative intelligence that gave birth to the universe is not separate from her true self. She knows that all of the ways that she is conditioned—biologically, socially, and psychologically—are not personal to her, but are part and parcel of a universal developmental process.
2. Trusting in Life
Through letting go of her need to control over and over again, she has discovered the empty Ground of Being that lies at the depth of her self. This profound experience of liberation frees her at the deepest level. As a result, she is at ease, manifesting an undefended innocence, dignity, and independence of spirit.

3. Taking Responsibility for Evolution
Knowing that the entire developmental process is One, she endeavors to take full responsibility for evolving her own consciousness, realizing that her development moves the leading edge forward for all womankind.

4. Realizing Unity with Other Women
She relaxes more and more into a unity with other women as she refuses to act out of the nearly universal compulsion for women to separate from and compete with each other. She doesn’t deny that this compulsion, which has been key to women’s survival in the past, operates in her psyche, nor is she afraid or ashamed of it, but she works to keep her focus on evolving women’s relationships through trust, transparency, and a passion to create the future.

5. Being Emotionally Rational
Despite how overwhelming any emotional experience may be, she strives for objectivity and aspires to liberate her power of choice so that she is no longer trapped by fears and desires rooted in her biological and cultural conditioning. She is developing the emotional maturity to not dis-integrate and give in to ancient survival impulses when she finds herself under pressure.

6. Standing Autonomously and Not Wavering
Rather than gauging her responses by what she thinks others want and need, she is cultivating a radical autonomy, grounded in her longing for liberation and her passion for the evolution of consciousness. She increasingly finds manipulative game-playing distasteful, and craves being simple, straight, and clear in her relationships with others.

7. Relinquishing Sexual Power
She is awake to how deeply identified she is with her sexual power and how instinctive it is to use it to get what she wants. Aspiring to drop this fundamental identification, she finds that sexual relationships become more straightforward and less of a priority and marker of personal success. The more she succeeds in this aspiration, the more she discovers a profound intimacy with others that is not related to sexuality at all.

8. Leading by Example
Dropping the many masks of pretense and self-image, she strives for a rare vulnerability and authenticity that is not emotional but comes from being unafraid of the impulses and motivations that drive women. She is discovering a deep confidence that is not edged with hardness but founded in transparency and humility. She is willing to step forward and be a pioneer, and does not abuse the power that comes with leadership.

9. Being Trustworthy
Resisting the temptation to be dishonest or inauthentic under scrutiny, she desires to act with integrity so that her word is her deed. She aspires to be consistently true to a higher purpose no matter what personal challenges she faces.

10. Rejecting Victimhood
She recognizes that she has cocreated history with men and is not a victim of it. She seeks to take full responsibility for her own choices, past and present. Today, she stands side by side with men as an equal cocreator of an enlightened future.

Source: EnlightenNext

 

 

Latent memory-calls come to life

Friday, May 18th, 2007
 

Artistic impression of nucleosomes interaction, by Mette Høst

Artistic impression of nucleosomes interaction, by Mette Høst

New research has examined the mechanisms behind latent cell memory, which can come to life and cause previously non-existent capacities suddenly to appear. Special yeast cells for example, can abruptly change from being of a single sex to hermaphrodite.

 

Background

Researchers from the Niels Bohr Institute have used mathematical models and computer simulations to examine fundamental mechanisms of cell memory. The research is an interdisciplinary cooperation between molecular biologists and physicists, and has just been featured on the cover of the prestigious science journal CELL.

Dormant capacities

Our genetic material – DNA – is a blueprint for how we look and are. This genetic material is very stable and it is faithfully transmitted to our descendants. Once in a while though, a change occurs to the DNA, either large or small. Changes in the DNA creating new functions normally arise by a slow and gradual process that involves natural selection operating over many generations.

Sometimes however, dramatic and very sudden changes are observed in one individual in the absence of any kind of change to the DNA:

”The explanation for the sudden changes is that it is not the DNA itself that is altered – it is its immediate surroundings that change and thereby cause a cell to activate some of its dormant capacities” says Kim Sneppen, professor in Biophysics at the Niels Bohr Institute.

Same inheritance – different traits

In the practical experiment molecular biologists used a mutant of a yeast cell which was bi-stable, in that it could become either of a single sex or hermaphrodite. The experiment showed that a spontaneous change occurred in the yeast cells about every 2000 cell-generations.

By building a mathematical model based on positive feedback from the microscopic state of the nucleosomes, the research group could simulate the experimental results and in this way gain insight into the mechanisms by which living cells with identical DNA can achieve extreme differentiation.

Contact:

Kim Sneppen, professor, Niels Bohr Institute, Copenhagen University

Tel: +45 3532-5352, Email: sneppen@nbi.dk

 

 

 

Source:

University of Copenhagen

On the (sound) track of anesthetics

Tuesday, March 6th, 2007
 

The figure shows a biologiccal membrane at its melting point. The green molecules are liquid, and the red are solid. Molecules of anesthetics reduce the number of red areas so that the sound pulse can no longer transport its signal. The nerve is anesthetised. Illustration by Heiko Seeger, PhD.

The figure shows a biologiccal membrane at its melting point. The green molecules are liquid, and the red are solid. Molecules of anesthetics reduce the number of red areas so that the sound pulse can no longer transport its signal. The nerve is anesthetised. Illustration by Heiko Seeger, PhD.

Physics explains biology

Every medical and biological textbook says that nerves function by sending electrical impulses along their length. ”But for us as physicists, this cannot be the explanation. The physical laws of thermodynamics tell us that electrical impulses must produce heat as they travel along the nerve, but experiments find that no such heat is produced,” says Associate Professor Thomas Heimburg from the Niels Bohr Institute at Copenhagen University. Instead, nerve pulses can be explained much more simply as a mechanical pulse. And such a pulse could be sound.

Sound versus electricity

Normally, sound propagates as a wave that spreads out and weakens. If, however, the medium in which the sound propagates has the right properties, it is possible to create localised sound pulses which propagate without spreading or losing their strength.

The membrane of the nerve is composed of lipids, a material that is similar to olive oil. This material can change its state from liquid to solid with temperature. Molecules that dissolve in membranes can lower the freezing point of membranes. The scientists found that the nerve membrane has a freezing point, which is precisely suited to the propagation of these concentrated sound pulses. Their theoretical calculations lead them to the same conclusion: Nerve pulses are sound pulses.

Anesthetised by sound

How is it possible to operate on a patient without pain? It has been known for more than 100 years that substances like ether, laughing gas, chloroform and the noble gas xenon can serve as anesthetics. These substances have very different chemical properties, but experience shows that their doses are strictly determined by their solubility in olive oil. In spite of this, no one knows precisely how anesthetics work and how the nerves are ”turned off”.

If a nerve is to be able to transport sound pulses and send signals, the membrane’s melting point must be sufficiently close to body temperature. The effect of anesthetics is simply to change the melting point – and when the melting point has been changed, sound pulses cannot propagate. The nerve is put on stand-by, and neither nerve pulses nor sensations are transmitted. The patient is anesthetised and feels nothing.

Contact:

Associate Professor Thomas Heimburg: phone +45 35 32 53 89, email: theimbu@nbi.dk

Professor Andrew Jackson: phone +45 35 32 52 32, email: jackson@nbi.dk

 

 

 

 

Source:

University of Copenhagen

Dark Energy

Thursday, January 18th, 2007
This is the part of the Universe that the research group ESSENCE has been observing. To the left you see a famous cluster of galaxes, Abell 168 Photo: Peter Challis

This is the part of the Universe that the research group ESSENCE has been observing. To the left you see a famous cluster of galaxes, Abell 168 Photo: Peter Challis

Researchers at the University of Copenhagen’s Dark Cosmology Centre at the Niels Bohr Institute have brought us one step closer to understanding what the universe is made of. As part of the international collaboration ESSENCE they have observed distant supernovae (exploding stars), some of which emitted the light we now see more than half the age of the universe ago. Using these supernovae they have traced the expansion history of the universe with unprecedented accuracy and sharpened our knowledge of what it might be that is causing the mysterious acceleration of the expansion of the universe.

Background and outline

At the end of last century astronomers discovered the startling fact that the expansion of our universe is not slowing down, as all our previous understanding of gravity had predicted. Rather the expansion is speeding up. Nothing in conventional physics can explain such a result. It means that either the universe is made up of around 70% ‘dark energy’ (something that has a sort of anti-gravity) or our theory of gravity is flawed.

Now, as part of the international collaboration “ESSENCE”, researchers at the Danish Dark Cosmology Centre have added a new piece to the puzzle. In two papers recently released they detail observations of supernovae (exploding stars) that allow them to trace the expansion history of the universe in unprecedented detail. ESSENCE is an extension of the original team that discovered the acceleration of the universe and these results push the limits of technology and knowledge, observing light from dying stars that was emitted almost half the age of the universe ago. 

In a third paper, led by the Danish team and released this week, the many new theories that have been proposed to explain the acceleration of the universe are critically assessed in the face of this new data. Dr. Jesper Sollerman and Dr. Tamara Davis lead the team who show that despite the increased sophistication in cosmological models over the last century the best model to explain the acceleration remains one that was proposed by Einstein back in 1917. Although Einstein’s reasoning at the time was flawed (he proposed the modification to his theory so it could support a static universe, because in those days everyone ‘knew’ the universe was not expanding, it may be that he was right all along.

Scientific details:

The primary aim of the experiment is to measure the ‘dark energy’ – the ‘thing’ that is causing the acceleration of the universe – to better than 10%. We measure the dark energy’s ‘equation of state’.  This also allows us to check whether our theory of gravity needs modification. So far it looks like our theory is correct and that the strange acceleration of the expansion of the universe can be explained by Einstein’s ‘cosmological constant’.

In modern terms the cosmological constant is viewed as a quantum mechanical phenomenon called the ‘energy of the vacuum’. In other words, the energy of empty space.  It is this energy that is causing the expansion to accelerate. The new data shows that none of the new theories that have been proposed in the last decade are necessary to explain the acceleration. Rather, vacuum energy is the most likely cause and the expansion history of the universe can be explained by simply adding this constant background of acceleration into the normal theory of gravity.

The ESSENCE team includes 38 top researchers from many different countries on four continents.

For further information contact:

Tamara Davis, Astrophysicist, Ph.D.
DARK Cosmology Centre, Niels Bohr Institute, University of Copenhagen,
Phone: +45 3532-5981, tamarad @ dark-cosmology.dk

Jesper Sollerman, Astrophysicist, Ph.D.
DARK Cosmology Centre, Niels Bohr Institute, University of Copenhagen,
Phone: +45 3532-5899, jesper @ astro.su.se