science tumbled

IBM takes a (feline) step toward thinking machines

Sat, 21 Nov 2009 22:03:00 +0100

IBM takes a (feline) step toward thinking machines:

IBM simulates a cat’s cerebral cortex using a supercomputer. The numbers are staggering: using almost 150,000 processors and 144 terabytes of memory, the program simulated the roughly 1 billion neurons and 10 trillion synapses (connections between neurons) of a cat’s brain. Even with this massive processing power, the simulation ran a hundred times slower than a real cat’s brain. (The researchers fed the artificial brain images of corporate logos. If I were a brain in a vat, I’d want my fantasy world to be a little livelier.)

A deeper question is whether this kind of simulation is telling us anything new. It seems — and this is, of course, extremely speculative, as is everything regarding actual artificial intelligence — entirely possible that we could duplicate a human brain in silicon, yet come no closer to understanding the brain’s operation. AI might be useful, but will it ever satisfy our very human curiosity about how and why stuff, in this case, the mind, works? Who knows. When dealing with the nature of consciousness, very little is certain.

Are you asleep? Exploring the mind's twilight zone

Sun, 25 Oct 2009 13:40:00 +0100

Are you asleep? Exploring the mind's twilight zone:

New Scientist:

Earlier this year, a puzzling report appeared in the journal Sleep Medicine. It described two Italian people who never truly slept. They might lie down and close their eyes, but read-outs of brain activity showed none of the normal patterns associated with sleep. Their behaviour was pretty odd, too. Though largely unaware of their surroundings during these rest periods, they would walk around, yell, tremble violently and their hearts would race. The remainder of the time they were conscious and aware but prone to powerful, dream-like hallucinations.

Both had been diagnosed with a neurodegenerative disorder called multiple system atrophy. According to the report’s authors, Roberto Vetrugno and colleagues from the University of Bologna, Italy, the disease had damaged the pair’s brains to such an extent that they had entered status dissociatus, a kind of twilight zone in which the boundaries between sleep and wakefulness completely break down (Sleep Medicine, vol 10, p 247).

An article about the breakdown between sleep and wakefulness, tying together a bunch of different phenomena, like morning grogginess, insomnia, sleep paralysis, sleepwalking, night terrors, “microsleep”, sleep deprivation and “mosaic sleep”, in which some parts of the brain fall asleep while the rest is awake — “It is like having a temporary mental disorder without anyone, including yourself, being aware of it.” Interesting stuff.

Reading, E-Books and the Brain

Mon, 19 Oct 2009 23:55:13 +0200

Reading, E-Books and the Brain:

Jonah Lehrer:

I think one of the most interesting findings regarding literacy and the human cortex is the fact that there are actually two distinct pathways activated by the sight of letters. (The brain is stuffed full of redundancies.) As the lab of Stanislas Dehaene has found, when people are reading “routinized, familiar passages” a part of the brain known as the visual word form area (VWFA, or the ventral pathway) is activated. This pathway processes letters and words in parallel, allowing us to read quickly and effortlessly. It’s the pathway that literate readers almost always rely upon.

But Dehaene and colleagues have also found a second reading pathway in the brain, which is activated when we’re reading prose that is “unfamiliar”. (The scientists trigger this effect in a variety of ways, such as rotating the letters, or using a hard to read font, or filling the prose with obscure words.) As expected, when the words were more degraded or unusual, subjects took longer to comprehend them. By studying this process in an fMRI machine, Dehaene could see why: reading text that was highly degraded or presented in an unusual fashion meant that we relied on a completely different neural route, known as the dorsal reading pathway. Although scientists had previously assumed that the dorsal route ceased to be active once we learned how to read, Deheane’s research demonstrates that even literate adults still rely, in some situations, on the same patterns of brain activity as a first-grader, carefully sounding out the syllables.

Did you slow down as you read the above? I know I did the moment I became conscious of the fact that I’m supposed to be able to read it effortlessly. (found here)

Jupiter's Moon Europa Has Enough Oxygen For Life

Sun, 18 Oct 2009 20:45:22 +0200

Jupiter's Moon Europa Has Enough Oxygen For Life:

Europa has more liquid water than the Earth. What has made the chances of finding life there seem small is that its sea lies under miles of ice. But now, scientists think enough oxygen reaches the sea to support not only bacteria but macroscopic life. (I say: forget manned missions to the Moon or Mars, let’s go to Europa!)

The inner life of the cell. I don’t think I’ve seen...

Tue, 13 Oct 2009 15:59:58 +0200

The inner life of the cell. I don’t think I’ve seen this one with voiceover narration before. Anyway, it’s a great video.

How Safe is the HPV vaccine? - Information Is Beautiful

Mon, 12 Oct 2009 19:43:13 +0200

How Safe is the HPV vaccine? - Information Is Beautiful:

gooneruk:

Given the amount of media fuss about the cervical cancer vaccine recently, particularly in the UK, this is very timely. And quite beautifully presented.

The most striking point is the difference between the odds of dying after the vaccine (15,200,000:1) and dying in a road accident the year after the vaccine (a mere 10,000:1).

Striking because the newspaper inches given to each of these causes of death is pretty much the reverse…

This math may not have many scientific applications, but...

Mon, 28 Sep 2009 01:35:00 +0200

This math may not have many scientific applications, but it’s simply beautiful: CellarAcademic explains infinite set theory in simple terms (parts one and two). Also, I took a stab at explaining some of this a while back. (via Tristan)

It’s Official: Water Found on the Moon Since man first...

Thu, 24 Sep 2009 23:21:45 +0200

It’s Official: Water Found on the Moon

Since man first touched the moon and brought pieces of it back to Earth, scientists have thought that the lunar surface was bone dry. But new observations from three different spacecraft have put this notion to rest with what has been called “unambiguous evidence” of water across the surface of the moon.

The moon remains drier than any desert on Earth, but the water is said to exist on the moon in very small quantities. One ton of the top layer of the lunar surface would hold about 32 ounces of water, researchers said.

Glass sculpture of E. coli, from Glass Microbiology. (via BB)

Fri, 11 Sep 2009 00:32:40 +0200

Glass sculpture of E. coli, from Glass Microbiology. (via BB)

Telegraphs Ran on Electric Air in Crazy 1859 Magnetic Storm

Fri, 04 Sep 2009 14:00:05 +0200

Telegraphs Ran on Electric Air in Crazy 1859 Magnetic Storm:

On September 2, 1859, the Earth witnessed the perfect solar storm. If anything on the same scale happened today, “the damage could range upwards of a $1 trillion, largely because of disruptions to the electrical grid.”

Scientific American has a great slideshow of ‘Spacecraft...

Wed, 02 Sep 2009 20:43:54 +0200

Scientific American has a great slideshow of ‘Spacecraft from Decades Past That Are Still Ticking.’ These spacecraft are marvels of engineering for far outlasting their intended lifespans.

Crossota millsae is a brilliant red and purple jellyfish also...

Wed, 02 Sep 2009 01:34:00 +0200

Crossota millsae is a brilliant red and purple jellyfish also found off California and Hawaii. This specimen was collected near the bottom of the Arctic Ocean in 2,000m of water.

Just one selection from a stunning collection of images taken in the frozen depths and featured by BBC Earth News.

Steely-Eyed Hydronauts of the Mariana

Sat, 15 Aug 2009 16:10:45 +0200

Steely-Eyed Hydronauts of the Mariana:

Damn Interesting is back, with the story of the one and only manned descent to the depths of the Mariana trench, the deepest point on the Earth’s surface, in 1960:

Partway into their long descent, Walsh and Piccard grew alarmed when they discovered they were no longer able to raise the mother ship on the sonar/hydrophone communication system, even after repeated attempts. The two men were thus left truly isolated from the outside world. Curled up in the cramped, cold, and dimly-lit sphere, the adventurers continued their hours-long downward journey with only one another’s voices and the occasional pop or groan from the Trieste’s strained hull to punctuate the anxious silence.

At approximately four hours into their descent–several thousand feet above the sea floor–a sharp clang sounded through the pressure sphere and the vehicle shuddered violently. Once their wincing subsided, the men did what they could to inspect the craft and its condition. It seemed that the water pressure at this never-before-encountered depth–six tons per square inch–had cracked the outer pane of the lucite window. For the moment the vehicle itself remained watertight, but the damage was worrisome. The Trieste was outfitted with a few safety systems; for instance, the ballast doors were held closed by electromagnets, so in the event of electrical failure the doors would fall open and drop the ballast, causing the vehicle to rise to the surface. But such systems would be of no help to the men inside if the 1,000 atmospheres of pressure crushed their delicate passenger compartment. Moreover, no other vehicle in existence was capable of reaching such depths, which meant that if her float tank became compromised there was no chance of rescue. Nevertheless, the stalwart scientists opted to press on.

About three quarters of an hour later, the bathyscaphe Trieste made history as its hull came to a gentle rest on the silty floor of the Challenger Deep abyss. The Trieste and her crew had spent four hours and forty-eight minutes in transit. The bathyscaphe instrumentation indicated a depth of 37,798 feet and external pressure of 1,099 atmospheres–approximately eight tons per square inch.

Apollo Mission Software

Fri, 07 Aug 2009 12:54:07 +0200

Apollo Mission Software:

Maybe you’re all tired of articles about the moon landing, but I found this description of the sheer dumb luck involved in the moon lander’s computer making a successful descent fascinating:

Allan’s descent program needed a routine to accurately estimate the new thrust level, which could be accomplished by reading the “delta-V” (change in velocity) measured by the LM’s accelerometers. He wrote a short routine that took into consideration, i.e., compensated for, the engine’s lag time, which TRW’s “interface control document,” full of useful information for the programmers, said was 0.3 seconds. It took 0.3 seconds for the LM’s descent engine to achieve whatever thrust level the computer might request. The final version of the thrust routine, which was put into the LM, was written by Allan’s friend Don Eyles. Eyles was sufficiently enthusiastic about the programming challenge that he found a way of writing it which required compensating for only 0.2 of the 0.3 seconds. The IBM 360 simulator showed Eyles’ program worked beautifully. His routine was aboard Apollos 11 and 12 which landed successfully. However, telemetry transmitted during the landings later showed something to be very wrong. The engines were surging up and down in thrust level, and were barley stable. A guy at Johnson Space Center called Allan and informed him that the LM’s engine was not a 0.3-second-lag engine after all. It had been improved some time before Apollo 11’s launch such as to lower the lag time to only 0.075 seconds. Correction of this item in the interface control document had simply been overlooked. Once this discrepancy was discovered, the IBM 360 simulator was reprogrammed to properly simulate the actual, faster engine. Running on the simulator, Don Eyle’s thrust program, with the 0.2-second compensation, exhibited the surging that had occurred on the real flights. But here’s the most interesting fact: the simulator also showed that had Allan Klumpp chose to “correct” Don Eyles’ program by compensating for the full 0.3 seconds that was printed in the document, the LM would have been unstable and Apollo 11 would never have been able to land. By pure luck, Don Eyles was creative enough to write the thrust routine in a way that kept the LM just inside the stability envelope and allowed successful landings!

Allan’s descent program called “P64” periodically computed a polynomial function to describe the optimum descent trajectory. This polynomial would smoothly merge the LM’s current position and velocity vectors into the target point position and velocity vector. The “target point” for P64 was just above the landing point (When the LM reached the target point with a small vertical descent rate, P64 would cease execution and the landing phase would be handled by a program called “P66”). The computer would then make the LM fly the trajectory, which would be recomputed every 2 seconds. An opportunity for disaster presented itself here. Many sci.space.tech readers may know enough mathematics to understand the undesirable “wiggles” that can be generated by high-order polynomial curve fits. Under conceivable circumstances, the polynomial function computed by P64 could droop down, go beneath the lunar surface, rise out of the surface, then descend to the target point! If such a trajectory were computed during a real landing, and the LM were allowed to follow it, the LM would crash. There was no logic coded in to detect this situation and prevent it. No programming solution was ever found. An example scenario where this disaster could have happened follows. If the LM was off course, away from the terrain model stored in the computer, and flying over a deep crater, the landing radar would fool the computer into thinking the LM was higher relative to the mean surface than it previously assumed. This could cause a newly computed polynomial trajectory to “droop” down sharply, unintentionally intersect the real lunar surface, then rise back out of the surface, inviting the LM to crash! Allan said this problem could also be caused by an astronaut retargeting the landing point beyond the fuel range.

Blue M&Ms linked to reducing spine injury The same blue food...

Tue, 28 Jul 2009 19:46:43 +0200

Blue M&Ms linked to reducing spine injury

The same blue food dye found in M&Ms and Gatorade could be used to reduce damage caused by spinal injuries. Researchers at the University of Rochester Medical Center found that when they injected the compound Brilliant Blue G (BBG) into rats suffering spinal cord injuries, the rodents were able to walk again, albeit with a limp. The only side effect was that the treated mice temporarily turned blue. (via)

Neil Armstrong and Buzz Aldrin ascend with the Lunar Module...

Mon, 20 Jul 2009 19:39:24 +0200

Neil Armstrong and Buzz Aldrin ascend with the Lunar Module Eagle after visiting the surface of the Moon, July 21, 1969, via APOD. Today, you probably know, is the 40th anniversary of the moon landing.

Dark flash photography

Mon, 20 Jul 2009 19:04:00 +0200

Dark flash photography:

New Scientist:

Dilip Krishnan and Rob Fergus at New York University have bult a “dark flash” camera which floods a scene with infrared and ultraviolet light that is invisible to the human eye. The image is crisp, but the colours are strange.

More here. (h/t)

We Choose the Moon

Thu, 16 Jul 2009 18:32:11 +0200

We Choose the Moon:

Don’t miss this one. To commemorate the 40th anniversary of the Apollo 11 mission to the moon, WeChooseTheMoon.org is broadcasting the mission in real-time, delayed by 40 years. Listen in to ‘live’ communications, follow the astronauts on twitter, and explore archival videos and photos. After Apollo lands on July 20th, all the content will be available for viewing at your own pace.

Pain? What pain?

Fri, 10 Jul 2009 02:56:38 +0200

Pain? What pain?:

In a recent study, men reported less pain when talking to female researchers, while women reported the same things regardless of the gender of the people they were reporting to. “Importantly though, their bodily responses were no different, suggesting that the physical sensation was probably the same, they just minimised it when talking to women.” Interesting.

jackjuly: The vast majority of Henrietta Lacks was dead by the...

Tue, 07 Jul 2009 19:55:56 +0200

jackjuly:

The vast majority of Henrietta Lacks was dead by the Fall of 1951, buried without a tombstone in Halifax County. Only 9 months earlier, she had been diagnosed with cervical cancer.

Cells from her cervical tumor were isolated, grown, and distributed. Due to the ability of some cancer cells to grow and divide without regard for their environment, these immortal cells quickly became a bottomless source of research material (without her consent), and were sent all over the world, and even into space (to determine whether human cells can survive zero gravity). The cells continue to divide today (above, via electron microscopy), in tens of thousands of laboratory incubators, and in such number that I wonder whether their mass now exceeds that of Lacks.