fuckyeah-chemistry:

Electrons are known to possess both particle and wave proprieties; and are able to surpass classically forbidden barriers as a result of their wavelike characteristics. This phenomenon is a quantum mechanical effect known as ‘tunneling.’ Scanning tunneling microscopy (STM) is an analytical technique that uses a piezoelectric tip to produce a tunneling current between a conducting or semi-conducting material and the tip; and ultimately results in a topographic map of the surface at a near-atomic level. An STM image of graphite is shown. The dark spots represent the centers of the 6-membered carbon rings. Using this technique, the lattice constant and bond length between adjacent carbon atoms can be calculated.

frontal-cortex:

Fig. 7. Effect of PDGF-BB on microfilament reorganization, as revealed by phalloidin staining. Quiescent mesonephric mesenchymal cells (A) were stimulated for 15 minutes (B) with PDGF-BB (10 ng/ml). Note that treated cells exhibit a rapid change in microfilament reorganization and in cellular morphology (phalloidin staining at the leading edge of the cell and extensions of lamellipodia). Bar, 20 μm.

Antonella Puglianiello et al, Expression and role of PDGF-BB and PDGFR-β during testis morphogenesis in the mouse embryo; Journal of Cell Science, March 1, 2004 vol. 117 no. 7 1151-1160

The role played by PDGF in testis morphogenesis is still incompletely understood. The present study investigates the expression and potential role of platelet-derived growth factor-BB (PDGF-BB) and its receptor, PDGF receptor β (PDGFR-β), during mouse testis cord formation, and the possibility that the growth factor may be involved in the migration to the gonad of mesenchymal cells of mesonephric origin.

ikenbot:

Artificial Brain Mimics Human Abilities and Flaws

Side Note: I recommend this fascinating article for anyone who’s been as interested in developments of the brain in the past couple of weeks or in general and the refreshing data about how our pattern recognition works and how it can lead to not only a better understanding of our own minds but also a better understanding into building more accurate artificial intelligence in robots. The accuracy and how natural the intelligence comes off is important if we are to have robots that work for and aid us, if we are to have extensions of what our technology can do with what we know about the human body and brain I think robotics is one way to go about it. It’s like using technology as a canvas and expressing our own biological makeup through it. In this article LS gets into a new software model that accurately replicates certain human-like mistakes with a very limited amount of virtual pattern recognizers. Excuse me for leaving the whole bit of the article I just found it too interesting to leave anything out.

Spaun, a new software model of a human brain, is able to play simple pattern games, draw what it sees and do a little mental arithmetic. It powers everything it does with 2.5 million virtual neurons, compared with a human brain’s 100 billion. But its mistakes, not its abilities, are what surprised its makers the most, said Chris Eliasmith, an engineer and neuroscientist at the University of Waterloo in Canada.

Ask Spaun a question, and it hesitates a moment before answering, pausing for about as long as humans do. Give Spaun a list of numbers to memorize, and it falters when the list gets too long. And Spaun is better at remembering the numbers at the beginning and end of a list than at recalling numbers in the middle, just like people are.

“There are some fairly subtle details of human behavior that the model does capture,” said Eliasmith, who led the development of Spaun, or the Semantic Pointer Architecture Unified Network. “It’s definitely not on the same scale [as a human brain],” he told TechNewsdaily. “It gives a flavor of a lot of different things brains can do.”

Eliasmith and his team of Waterloo neuroscientists say Spaun is the first model of a biological brain that performs tasks and has behaviors. Because it is able to do such a variety of things, Spaun could help scientists understand how humans do the same, Eliasmith said. In addition, other scientists could run simplified simulations of certain brain disorders or psychiatric drugs using Spaun, he said.

A brain with thought and action

Researchers have made several brain models that are more powerful than Spaun. The Blue Brain model at the Ecole Polytechnique Fédérale de Lausanne in France has 1 million neurons. IBM’s SyNAPSE project has 1 billion neurons. Those models aren’t built to perform a variety of tasks, however, Eliasmith said.

Spaun is programmed to respond to eight types of requests, including copying what it sees, recognizing numbers written with different handwriting, answering questions about a series of numbers and finishing a pattern after seeing examples.

Spaun’s myriad skills could shed light on the flexible, variable human brain, which is able to use the same equipment to control typing, biking, driving, flying airplanes and countless other tasks, Eliasmith said. That knowledge, in turn, could help scientists add flexibility to robots or artificial intelligence, he said. Artificial intelligence now usually specializes in doing only one thing, such as tagging photos or playing chess. “It can’t figure out to switch between those things,” he said.

In addition, artificial intelligence isn’t built to mimic the cellular structure of human brains as closely as Spaun and other brain models do. Because Spaun runs more like a human brain, other researchers could use it to run health experiments that would be unethical in human study volunteers, Eliasmith said. He recently ran a test in which he killed off the neurons in a brain model at the same rate that neurons die in people as they age, to see how the dying off affected the model’s performance on an intelligence test.

Such tests would have to be just first steps in a longer experiment, Eliasmith said. The human brain is so much more complex than models that there’s a limit to how much models are able to tell researchers. As scientists continue to improve brain models, the models will become better proxies for health studies, he said.

Next up: a brain in real time

There’s one major way Spaun differs from a human brain. It takes a lot of computingpower to perform its little tasks. Spaun runs on a supercomputer at the University of Waterloo, and it takes the computer two hours to run just one second of a Spaun simulation, Eliasmith said.

So Eliasmith’s next major step for improving Spaun is developing hardware that lets the model work in real time. He’ll cooperate with researchers at the University of Manchester in the U.K. and hopes to have something ready in six months, he said.

In the far future, people may find Spaun’s humanlike flaws deliberately built into robot assistants, Eliasmith said. “Those kinds of features are important in a way because if we’re interacting with an agent and it has a kind of memory that we’re familiar with, it’ll more natural to interact with,” he added.

Eliasmith and his colleagues published their latest paper about Spaun today (Nov. 29) in the journal Science.

ikenbot:

The Other Red Planet: Soviet Union Scored an Interplanetary First at Venus 45 Years Ago

Illustration: A piloted flyby spacecraft releases a robotic probe (Venera 4) into the cloudy atmosphere of Venus. / NASA

The U.S.S.R.’s Venera 4 was the first spacecraft to return data from inside another planet’s atmosphere

If Venus’s pass across the sun earlier this week yields a bounty of information for hunters of transiting worlds in other planetary systems, it’s because Venus is a known entity. Studying the June 5 Venus transit as if it were a faraway exoplanet “gives us a reality check,” says planetary physicist Colin Wilson of the University of Oxford. “We can check on all those exoplanet techniques to see how accurate they really are.” Such data may enhance NASA’s Kepler mission as well as the many ground-based campaigns using planetary transits to identify distant worlds, a method that has led to the discovery or characterization of more than 200 exoplanets.

That reality check would not be possible without the data planetary scientists already have about Venus. And humanity’s up-close exploration of Earth’s cloud-shrouded closest neighbor began in earnest 45 years ago, when the Soviet probe Venera 4 launched on June 12, 1967.

The first two Veneras had failed after launch. Venera 3, launched in 1965, is thought to have crashed on Venus but returned no data.

At last, on October 18, 1967, Venera 4 became the first man-made object to enter another planet’s atmosphere and send back data. “It was before any Mars landers or anything,” Wilson says. And it changed our view of Earth’s sister planet forever.

Full Article

sciencenote:

Did anyone else have this problem as a child?

sciencenote:

Quantum mechanics is defined as, “[a] framework of laws governing the universe whose unfamiliar features such as uncertainty, quantum fluctuation, and wave-particle duality become most apparent on microscopic scales of atoms and subnuclear [sic] particles” (NOVA – The Elegant Universe); this is the mechanism by which quantum physics operates. Quantum physics, as a “discovery,” as well as a discipline, has its roots in the early 1900s. “In 1905, the accepted and proven theory of light was the light was a wave phenomenon.” However, “In spite of this, Einstein published his famous paper proposing that light was a particle phenomenon” (Zukav 133). And so, the wave-particle duality existent in modern physics, as we know it, is born. Zukav goes on to say, “Einstein’s thesis led to the wave-particle duality from which quantum mechanics emerged and [brought] with it, [ … ] a way of looking at reality and ourselves that is vastly different from that to which we were accustomed” (134). This “discovery” of existent duality was not alone in the realm of physics. For example, the duality of bourgeoisie/proletariat was beginning to rise in the consciousness of the masses during this time – along with the duality existent in socio-political spheres in the form of collectivism vs. individualism: the “greater” duality which essentially caused socialist (and inevitably communist) uprising (symbolic of the rise of post-modern thought, creating the “greatest” duality existent during this time: modern vs. post-modern). These various events were part of a “collective consciousness,” which the Chinese would consider to be similar to the “Western” notion of the soul.