| Physical limits of inference |
| Deep in the deluge of knowledge that poured forth from science in the 20th century were found ironclad limits on what we can know. Werner Heisenberg discovered that improved precision regarding, say, an object’s position inevitably degraded the level of certainty of its momentum. Kurt Gödel showed that within any formal mathematical system advanced enough to be useful, it is impossible to use the system to prove every true statement that it contains. And Alan Turing demonstrated that one cannot, in general, determine if a computer algorithm is going to halt. |
| David H. Wolpert, a physics-trained computer scientist at the NASA Ames Research Center, has chimed in with his version of a knowledge limit. Because of it, he concludes, the universe lies beyond the grasp of any intellect, no matter how powerful, that could exist within the universe.Read more at www.scientificamerican.com |
| Locked in a struggle with a nuclear- armed Soviet Union, the US government in the ’60s chose to build uranium-fueled reactors — in part because they produce plutonium that can be refined into weapons-grade material. The course of the nuclear industry was set for the next four decades, and thorium power became one of the great what-if technologies of the 20th century. |
| Industry players are looking into thorium, and governments from Dubai to Beijing are funding research. India is betting heavily on the element. |
| the Energy From Thorium team helped produce a design for a new liquid fluoride thorium reactor, or LFTR (pronounced “lifter”), which, according to estimates by Sorensen and others, would be some 50 percent more efficient than today’s light-water uranium reactors. |
| Annual fuel cost for 1-GW reactor $50-60 million |
Seems to be very logical, but how can such condition be helped? Sophisticated scans showed the brains of people with autism are less active when engaged in self-reflective thought. |
The researchers used functional magnetic resonance scans to measure brain activity in 66 male volunteers, half of whom had been diagnosed with an autistic spectrum disorder. |
They were particularly interested in part of the brain called the ventromedial pre-frontal cortex (vMPFC) - known to be active when people think about themselves. |
The researchers found this area of the brain was more active when typical volunteers were asked questions about themselves compared with when they were thinking about the Queen. |
However, in autism this brain region responded equally, irrespective of whether they were thinking about themselves or the Queen. |
Researcher Michael Lombardo said the study showed that the autistic brain struggled to to process information about the self. Read more at news.bbc.co.uk |
Now _this_ sounds thrilling… | At the SC09 conference in Portland, Ore., Big Blue said its team had tapped the power of Lawrence Livermore’s Blue Gene/P supercomputer (147,456 CPUs and 144 terabytes of main memory) to perform the first near real-time simulation of a brain the size of a cat’s, a program that modeled 1 billion spiking neurons and 10 trillion individual learning synapses. (The simulation initially ignored the researchers completely, then demanded to be let outside.) |
| Additionally, working with researchers from Stanford and elsewhere, IBM scientists developed an algorithm to “noninvasively measure and map the connections between all cortical and sub-cortical locations within the human brain using magnetic resonance diffusion weighted imaging,” producing a wiring diagram that will help illuminate the way the organ processes information. |
| Overwork may hasten the aging-related decline in memory and thinking skills, according to a long-term study of British civil servants. |
| Between 1997 and 1999, and again between 2002 and 2004, 2,214 of the volunteers completed tests designed to measure cognitive function. The tests evaluated verbal memory and skills, fluid intelligence (associated with short-term memory, abstract thinking, creativity, and problem solving), and crystallized intelligence (learning accumulated over the life span in education, work, and cultural experiences) |
| Compared with the participants who reported working 40 or fewer hours a week, those who worked more than 55 hours a week had lower scores on the vocabulary tests at the start and the follow-up assessments. They also showed a larger decline in fluid intelligence from the first set of tests to the second. Read more at blogs.harvardbusiness.org |
Interesting approach. A bit more about the research itself:
The researchers suggest that the probability of a word being activated in memory lies somewhere between Spreading Activation (in which words are individually recalled based on individually calculated conceptual distance) and Spooky Activation at a Distance (in which the cue word simultaneously activates the entire associative structure). Most likely, Spreading Activation underestimates the strength of activation, while Spooky Activation at a Distance overestimates the strength of activation.
“Even though both the Spreading Activation and Spooky-Activation-at-a-Distance models are based on an underlying network, both models are still fundamentally reductive in nature and assume that words are separate, distinct entities in human memory,” Bruza explained. On the other hand, the quantum-based model doesn’t assume that words are separate entities.
In the new model, associative word recall probability depends on how strongly connected the associated words are to each other. For instance, “Earth” and “space” are entangled in the context of “planet,” but “Earth” and “gas giant” may not be entangled (though “Jupiter” and “gas giant” may be). Words that are entangled with many other words have a greater probability of being recalled, while words that are entangled with few or no other words have a smaller recall probability.
Wonder how it can be applied on practice… we don’t have yet the whole network of our concepts catalogued, mapped and visualized, but this seems to be one of the possible steps that can lead towards it.
| Researchers have modeled the human mental lexicon as consisting of words that cannot be separated from other words, which may explain why words have many associations, a feature which helps us communicate. |
“We take the position that quantum entanglement in modern physics is a physical manifestation of something more general called ‘non-separability,’” coauthor Peter Bruza of QUT told PhysOrg.com. “We view quantum theory as an abstract framework for developing models of non-separability in a variety of domains including cognition. Note that, even though we are using quantum theory to model the non-separability of words in human memory, we make no claim that this corresponds to a physical manifestation of entanglement in the brain.” |
| This kind of research is an example of an emerging field called “quantum cognition,” the aim of which is to use quantum theory to develop radically new models of a variety of cognitive phenomena ranging from human memory to decision making.Read more at www.physorg.com |
Interesting additional info from the text:
Edward Large, a neuroscientist at Florida Atlantic University at Boca Raton, has found that rhythmic sounds can entrain gamma brain waves, causing the beginning of each sound to be accompanied by a burst of several especially strong wave peaks. The click train may entrain other types of brain waves too - perhaps those that correspond to the discrete snapshots in our perceptions.
VanRullen and Jones agree that this may be the answer. “When you have faster oscillations, you have more snapshots per second,” says VanRullen. “You may be more efficient at particular cognitive tasks, and because there are more snapshots in a given time, it may seem to last for longer.”
If this theory is correct, the click train is literally resetting the brain’s frame-capture rate.
So, not only the brain has a number of clock rates which govern the processing of information, but there could be some tricks to overclock it?..
| Perhaps the most fundamental question neuroscientists are investigating is whether our perception of the world is continuous or a series of discrete snapshots like frames on a film strip. Understand this, and maybe we can explain how the healthy brain works out the chronological order of the myriad events bombarding our senses, and how this can become warped to alter our perception of time. |
So it seems that each separate neural process that governs our perception might be recorded in its own stream of discrete frames. But how might all these streams fit together to give us a consistent picture of the world? Ernst Pöppel, a neuroscientist at the Ludwig Maximilian University in Munich, Germany, suggests all of the separate snapshots from the senses may feed into blocks of information in a higher processing stream. He calls these the “building blocks of consciousness” and reckons they underlie our perception of time (Philosophical Transactions of the Royal Society B, vol 364, p 1887). Read more at www.newscientist.com |
Don’t completely agree with labelling “Unified Communications” as “dropped”, though. (May be “Uniformed Communications” would be more accurate term?)
The general idea–shared computing services accessible over the Internet that can expand or contract on demand–topped Gartner’s list of the 10 top
technologies that information technology personnel need to plan for. It’s complicated, poses security risks, and computing technology companies are latching onto the buzzword in droves, but the phenomenon should be taken seriously, said analyst Dave Cearley here at the Gartner Symposium.
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Will there come a day when we will be able to debug the brain, I wonder?
| The study demonstrates that a small piece of the brain can compute three different things at different times – within a quarter of a second – and shows that Broca’s area doesn’t just do one thing when processing language. |
| The discoveries came through the researchers’ use of a rare procedure in which electrodes were placed in the brains of patients. |
| The procedure, called Intra-Cranial Electrophysiology (ICE), allowed the researchers to resolve brain activity related to language with spatial accuracy down to the millimeter and temporal accuracy down to the millisecond. |
This is the first experiment to use ICE to document how the human brain computes grammar and produces words. |
| “These results suggest that Broca’s area actually consists of several overlapping parts, performing distinct computational steps in a tightly timed choreography, a dance that may simply have been undetectable due to the level of resolution of previous methods.”Read more at www.sciencedaily.com |
Personally, I keep wondering whether the effects of internet, TV and other similar addictions could not also be explained as people seeking a plausible substitute when their (a bit misterious) “default network” is not working properly… or just because it takes less energy to imitate it this way, and people tend to use as little energy as possible?..
I remember reading another article some time ago which established a link between children who watch TV too much and the fact that they produced less creative work, which was seen as the sign that their “default network” could have problems… in that article, the TV addiction was seen as the origin of the problem, but could it also be otherwise, or at least, mutually enhancing? Ever find yourself sitting down at the computer just for a second to find out what other movie you saw that actress in, only to look up and realize the search has led to an hour of Googling? Thank dopamine. Our internal sense of time is believed to be controlled by the dopamine system. People with hyperactivity disorder have a shortage of dopamine in their brains, which a recent study suggests may be at the root of the problem. For them even small stretches of time seem to drag. An article by Nicholas Carr in the Atlantic last year, “Is Google Making Us Stupid?” speculates that our constant Internet scrolling is remodeling our brains to make it nearly impossible for us to give sustained attention to a long piece of writing. Like the lab rats, we keep hitting “enter” to get our next fix. Read more at mindblog.dericbownds.net |
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