According to the New England Journal of Medicine, after thirty years of silence, authors of a standard clinical psychiatric bedside test have issued take down orders of new medical research.... Read more »
When a star becomes a white dwarf — an old, extremely dense star that would have once been similar to our own Sun — the eventful part of its life is over. It releases what heat and light it has left over billions of years, slowly cooling until it no longer shines. Usually. Some white dwarfs, however, are not content with this ending....... Read more »
Li W, Bloom JS, Podsiadlowski P, Miller AA, Cenko SB, Jha SW, Sullivan M, Howell DA, Nugent PE, Butler NR.... (2011) Exclusion of a luminous red giant as a companion star to the progenitor of supernova SN 2011fe. Nature, 480(7377), 348-50. PMID: 22170681
Nugent PE, Sullivan M, Cenko SB, Thomas RC, Kasen D, Howell DA, Bersier D, Bloom JS, Kulkarni SR, Kandrashoff MT.... (2011) Supernova SN 2011fe from an exploding carbon-oxygen white dwarf star. Nature, 480(7377), 344-7. PMID: 22170680
A brief historical account on optical and vision research in Spain in the XX century... Read more »
Marcos, Artal, Santamaría, Aguilar, Plaza. (2006) Research in Physiological Optics in Spain: A historical revision. Opt. Pura Apl. 39 (3) 189-197 . info:/
After trying the hand-warmer my friend gave me for Christmas I thought, “cool, I wonder how this works?” Here’s the hand-warmer in action: So what’s going on? The hand-warmer heats up when you bend the metal disk that’s inside the pouch. Bending the disk causes the liquid inside the hand-warmer to solidify. This change [...]... Read more »
How does Santa visit billions of homes all around the globe in just one night? The last important scientific question in the world has been solved! ... Read more »
How does Santa visit billions of homes all around the globe in just one night? The last important scientific question in the world has been solved!... Read more »
Aesop told the fable of a thirsty crow that came upon a nearly empty pitcher of water and discovered that by dropping pebbles in, he could raise the water to a drinkable level. The moral is "Little by little does the trick"--or was that "Necessity is the mother of invention"? Either way, scientists have enjoyed testing non-fictional members of the clever corvid family with this puzzle. Most recently, wild crows showed scientists they're smart enough for a whole barrage of Aesop-inspired challenges.
New Zealand psychologist Alex Taylor led the study of five New Caledonian crows that had been captured from the wild. The birds (Caesar, Laura, Bess, Mimic and Pepe, since you asked) were each given an extensive series of tests while visually separated from their peers. Like one of those computer games where you walk into a dead-end room and have to find the secret button that opens a submarine hatch and takes you someplace more interesting, the crows were presented with varied apparatuses and had to figure out which objects were tools that would help get a tasty treat into their beaks.
The tests began with the classic "Aesop's fable paradigm." Crows saw a tube partially filled with water. Inside the tube was a bite of meat, stuck onto a piece of wood that floated below their reach. Small stones were sitting nearby. If you're thinking that you might not have been able to solve this puzzle, rest assured--the birds didn't get it either.
After making sure the crows didn't naturally know how to solve the puzzle, the researchers gave the birds a hint. This time, the crows saw the same tube, floating meat, and stones. But there was a platform next to the top of the tube with a couple stones sitting on it, too. As the crows attempted to jam their beaks far enough into the tube to reach the meat, they tended to accidentally knock the stones into the tube. After doing this several times and noticing how the water level rose, all the crows eventually figured out the trick. They began dropping stones into the tube on purpose to get the meat.
Although this looks pretty clever, it's possible that the birds found the solution by simple association: "Stones mean food. Mess around with the stones, or put them near the food, and the food gets in my beak." So the researchers followed up with a series of puzzles that tested what the crows actually understood.
(Only four crows were used in most of the experiments--poor Bess, perhaps believing herself to be in one of those fables where the crow gets eaten by an alligator, was too afraid of the testing apparatus to participate.)
In one test, the crows were given stones of two different sizes. They quickly began ignoring the smaller stones in favor of larger ones, which raised the water level faster. (Laura, the smartypants of the bunch, never once used a small stone.) In another test, the stones were replaced with white chunks of rubber and styrofoam. Though they looked the same, the former item was heavy and useful, while the latter uselessly floated on top of the water. Again, the crows picked up on the difference, learning after a few trials to discard the styrofoam chunks and throw the rubber ones into the tube. In this video, you can see Mimic mastering the puzzle on his first try (and adorably peeking into the tube to make sure the meat is still there).
The crows seemed to understand what was important about the objects they were using as tools: bigger and heavier items would get the meat to them faster. But did they grasp what was happening inside the tube? To test the birds' understanding of the water in the tube, researchers showed them a tube of water next to a tube of sand. Both had the usual chunk of meat sitting on their surface, but throwing rocks into the tube of sand would accomplish nothing. The crows soon learned this, more or less, and dropped most of their rocks into the water tube. In this video, smartypants Laura ignores the sand tube entirely in her fourth trial. When the tube of water was paired with a tube of air, the crows again learned to put most of their stones into the water tube--though they dropped a fair number of stones into the air tube as well, apparently struggling to grasp that one clear substance wasn't the same as the other.
New Caledonian crows use sticks as tools in the wild to dig grubs out of holes, and showed here that they can learn to use other kinds of tools as well. This suggests that using tools, for the crows, is true problem solving and not just an ingrained behavior (like your dog kicking up imaginary dirt on the sidewalk after it poops). And the birds' performance with different sizes and shapes of "rocks" shows that they can adapt their tool use to various conditions--though they did struggle a bit with the tubes of air and sand. Buoyancy is tricky for everyone.
With the crow-and-pitcher paradigm nearly exhausted, maybe scientists will turn to Aesop's other fables for future studies. Are crows susceptible to flattery when holding pieces of cheese? Do foxes eat grapes (sour or otherwise)? And, of course, does slow and steady really win the race?
Images: Project Gutenberg/Wikimedia Commons; Taylor et al. (video screengrab)
Taylor, A., Elliffe, D., Hunt, G., Emery, N., Clayton, N., & Gray, R. (2011). New Caledonian Crows Learn the Functional Properties of Novel Tool Types PLoS ONE, 6 (12) DOI: 10.1371/journal.pone.0026887... Read more »
Taylor, A., Elliffe, D., Hunt, G., Emery, N., Clayton, N., & Gray, R. (2011) New Caledonian Crows Learn the Functional Properties of Novel Tool Types. PLoS ONE, 6(12). DOI: 10.1371/journal.pone.0026887
If you study enough history of science, you learn that the things that scientists are most famous for are often not their only work of interest — or even the most fascinating thing they’ve done! The significance of a scientist’s … Continue reading →... Read more »
Edmond Halley. (1714) The Art of Living under Water: Or, a Discourse concerning the Means of furnishing Air at the Bottom of the Sea, in any ordinary Depths. Philosophical Transactions, 492-499. info:/
I came across an article on the new research by Kane and Mertz which supposedly disproves the “greater male variability” hypothesis. That is, while averages for both genders are approximately the same, males have more variance in their intelligence. Thus, when intelligence tested, you’ll see more males at both the upper and lower tails of the [...]... Read more »
Jonathan M. Kane and Janet E. Mertz. (2011) Debunking Myths about Gender and Mathematics Performance. Notices of the American Mathematical Society, 10. info:/
Few things are as reviled on popular science and physics comment sections as dark matter and dark energy because aside from indirect observations, we’ve never actually detected either. We can see that something is pushing galaxies apart from each other while another invisible force holds these galaxies together, but there have been many attempts to do away with both in a theoretical sense. [...]... Read more »
Carati A. (2011) Gravitational effects of the faraway matter on the rotation curves of spiral galaxies. n/a. arXiv: 1111.5793v1
The unification of forces, sought after for a long time, and the incompatibility of standard mechanics of gravity on the quantum scale has been a holy grail of sorts for physicists to resolve. Now if we look at the nature of standard black holes, not protons, we can't forget that they exist as a singularity on a quantum level. All we know of black holes then should apply to these schwarzschild protons. This new theory debunks black hole evaporation. Stephen Hawking will be angered.
Strong force here is conveniently renamed as gravity. It's not necessarily a revelation, that aspect is only a revelation based on simple semantics. Try to explain how black holes are now, under your theory, positively charged, as protons are already confirmed to be.... Read more »
Nassim Haramein. (2010) The Schwarzschild Proton . AIP. info:other/
In a nondescript office park outside Vancouver with views of snow capped mountains in the distance is a mirrored business park where very special work is being done. The company is D-Wave, the quantum computing company. D-Wave's mission is to build a computer which will solve humanity's grandest challenges.D-Wave aims to develop the first quantum computer in the world, perhaps they already have. The advent of quantum computers would be a sea change in the world that would allow for breaking of cryptography, better artificial intelligence, and exponential increases in computing speed for certain applications. The idea for quantum computers has been bubbling since Richard Feynman first proposed that the best way to simulate quantum phenomena would be with quantum systems themselves, but it has been exceedingly difficult to engineer a computer than can manipulate the possibilities of quantum information processing. Hardly a decade ago D-Wave began with a misstep which is the origin of their name. D-Wave got its name from their first idea which would have used yttrium barium copper oxide (YBCO) which is a charcoal looking material with a superconducting temperature above that of the boiling point of liquid nitrogen. This means that YBCO is the standard science lab demonstration of superconducting magnetic levitation. Ultimately the crystalline structure of YBCO was found to be an imperfect material, but the cloverleaf d-wave atomic orbital that lends YBCO its superconducting properties stuck as D-Wave's name. The vision of D-Wave did not change, but their approach did. They realized they would have to engineer and build the majority of the technology necessary to create a quantum computer themselves. They even built built their own superconducting electronics foundry to perform the electron beam lithography and metallic thin film evaporation processes necessary to create the qubit microchips at the heart of their machine.I recently got to visit D-Wave, the factory of quantum dreams, for myself. The business park that D-Wave is in is so nondescript that we drove right by it at first. I was expecting lasers and other blinking lights, but instead our University of Washington rented van pulled into the wrong parking lot which we narrowly reversed out of. In the van were several other quantum aficionados, students, and professors, mostly from computer science who were curious at what a quantum computer actually looks like. I am going to cut the suspense and tell you now that a quantum computer looks like a really big black refrigerator or maybe a small room. The chip at the heart of the room is cooled to a few milikelvin, colder than interstellar space, and that is where superconducting circuits count electric quantum sheep. The tour began with us milling around a conference room and our guide, a young scientist and engineer, was holding in his hand a wafer which held hundreds of quantum processors. I took a picture and after I left that conference room they did not let me take any more pictures.Entering the laboratory it suddenly dawned on me that this wasn't just a place for quantum dreams it was real and observable. The entire notion of a quantum computer was more tangible. A quantum computer is a machine which uses quantum properties like entanglement to perform computations on data.The biggest similarity between a quantum computer and a regular computer is that they both perform algorithms to manipulate data. The data, or bits, of a quantum computer are known as qubits. A qubit is not limited to the values of 0 or 1 as in a classical computer but can be in a superposition of these states simultaneously. Sometimes a quantum computer doesn't even give you the same answer to the exact same question. Weird. The best way to conceive of a quantum computing may be to imagine a computation where each possible output of the problem has either positive or negative probability amplitudes (a strange quantum idea there) and when the amplitudes for wrong answers cancel to zero and right answers are reinforced.The power of quantum computers is nicely understood within the theoretical framework of computational complexity theory. Say for example that I give you the number 4.60941636 × 1018 and ask for the prime factors of this number. Now if someone were to give you the prime factors you could verify them as correct very quickly, but what if I asked you to generate the prime factors for me (I dare you. I have the answer. I challenge you). The quintessential problem here is the P versus NP question which asks whether if a problem can be verified quickly can it also be solved quickly. Quickly is defined as polynomial time meaning that the algorithm scales as the number of some inputs to some power. Computational complexity theory basically attempts to categorize different kinds of problems depending on how fast a solution can be found as the size of the problem grows. A P class problem is one in which the solution can be found within polynomial time. A NP class problem is one in which the solution can be verified in polynomial time. So if I ask you for the prime factors of my number above that is an NP problem because given the numbers you could verify the answer quickly, but it would be very difficult to calculate the numbers just given the number. It is an open question, but it appears likely that all P problems are a subset of NP. This means that problems verifiable in polynomial time are not necessarily solved in polynomial time. The issue is that for some very interesting problems in the real world we could verify the answer if we stumbled upon it, but we won't even be able stumble upon the answer in a time shorter than the age of the universe with current computers and algorithms. What we know we know and what we think we know is a sea of confusion, but the popular opinion and where people would take their wagers is that P is not equal to NP.Suddenly, with mystique and spooky actions at a distance, quantum computing comes swooping in and claims to be able to solve some NP problems and all P problems very quickly. A general quantum computer would belong to the complexity class of BQP. There is a grand question at hand, is BQP in NP? (More generally, is BQP contained anywhere in the polynomial hierarchy? The polynomial hierarchy is a complexity class which generalizes P and NP problems to a particular kind of perfect abstract computer with the ability to solve decision problems in a single step. See this paper here on BQP and the Polynomial Hierarchy by Scott Anaronson who is a outspoken critic of D-Wave) At this time we cannot even claim to have evidence that BQP is not part of NP, but most scientists close to the problem think that BQP is not a subset of NP. Quantum computing researchers are trying to get better evidence that quantum computers cannot solve NP-complete problems in polynomial time (if NP was a subset of BQP then the polynomial hierarchy collapses). A reasonable wager I would take is that P is a (proper) subset of BQP and BQP is itself is a (proper) subset of NP. This claim has not been rigorously proved but it is suspected to be true and further there are some NP problems which it has been shown to be true for such as prime factorization and some combinatoric problems.There might be an elephant in the room here. The D-Wave architecture is almost certainly attacking a NP complete problem and reasonable logic says that quantum computers will solve P problems and some NP problems, but not NP complete problems (this is also not proven, but suspected). An NP complete problem is a problem in which the time it takes to compute the answer may reach into millions or billions of years even for moderately large versions of the problem. Thus we don't know if this particular quantum computer D-Wave has built even allows us to do anything efficiently we couldn't already do on a classical computer efficiently; it doesn't seem to be a BQP class computer thus it cannot for example solve prime factorization cryptography problems. So, yes it is a quantum machine, but we don't have any evidence it is an interesting machine. At the same time we don't have any evidence it is an uninteresting machine. It is not general purpose enough to be clear it a a big deal, nor is it so trivial it is totally uninteresting.The D-Wave lab was bigger than I expected and it was at once more cluttered and more precise than I thought it would be. It turns out the entire process of quantum computing follows this trend. There are a lot of factors they contend with and on the tour I saw people dead focused with their eyes on a microscope executing precise wiring, coders working in pairs, theoreticians gesturing at a chaotic white board, and even automated processes being carried on by computers with appropriately looking futuristic displays. The engineering problems D-Wave faces include circuit design, fabrication, cryogenics, magnetic shielding and so on. There is too much to discuss here so I will focus on what I think are scientifically the two most interesting parts of the D-Wave quantum computer which are the qubit physics and the quantum algorithm which they implement; in fact these two par... Read more »
Harris, R., Johansson, J., Berkley, A., Johnson, M., Lanting, T., Han, S., Bunyk, P., Ladizinsky, E., Oh, T., Perminov, I.... (2010) Experimental demonstration of a robust and scalable flux qubit. Physical Review B, 81(13). DOI: 10.1103/PhysRevB.81.134510
Harris, R., Johnson, M., Han, S., Berkley, A., Johansson, J., Bunyk, P., Ladizinsky, E., Govorkov, S., Thom, M., Uchaikin, S.... (2008) Probing Noise in Flux Qubits via Macroscopic Resonant Tunneling. Physical Review Letters, 101(11). DOI: 10.1103/PhysRevLett.101.117003
Symphonies are some of the most complex musical pieces. They involve different instruments, each with their own unique sound, and each instruments section playing their own tunes. Yet, what are symphonies in comparison to the complexity of life? Proteins for example, they are made of a limited number of building blocks, amino acids, but take [...]... Read more »
Spivak, D., Giesa, T., Wood, E., & Buehler, M. (2011) Category Theoretic Analysis of Hierarchical Protein Materials and Social Networks. PLoS ONE, 6(9). DOI: 10.1371/journal.pone.0023911
Giesa, T., Spivak, D., & Buehler, M. (2011) Reoccurring Patterns in Hierarchical Protein Materials and Music: The Power of Analogies. BioNanoScience, 1(4), 153-161. DOI: 10.1007/s12668-011-0022-5
While CERN is calming down rumors (see here), research activity on Yang-Mills theories keeps on going on. A few days ago, a paper by Axel Weber appeared on arxiv (see here). As my readers know, having discussed this at length, in these last years there has been a hot debate between the proponents of the [...]... Read more »
Axel Weber. (2011) Epsilon expansion for infrared Yang-Mills theory in Landau gauge. arXiv. arXiv: 1112.1157v1
In a world where high-speed neutrinos and melting ice caps hog the limelight, it’s sometimes nice to pay tribute to the sillier side of science. Because for every Einstein there’s a physicist trying to understand why toast always lands butter-side down; for every Darwin, a biologist who studies fish farts.... Read more »
Bubier NE, Paxton CG, Bowers P, & Deeming DC. (1998) Courtship behaviour of ostriches (Struthio camelus) towards humans under farming conditions in Britain. British Poultry Science, 39(4), 477-81. PMID: 9800029
Edgeworth R, Dalton BJ, & Parnell T. (1984) The Pitch Drop Experiment. European Journal of Physics, 198-200. info:/
Maguire EA, Gadian DG, Johnsrude IS, Good CD, Ashburner J, Frackowiak RS, & Frith CD. (2000) Navigation-related structural change in the hippocampi of taxi drivers. Proceedings of the National Academy of Sciences of the United States of America, 97(8), 4398-403. PMID: 10716738
Wilson B, Batty RS, & Dill LM. (2004) Pacific and Atlantic herring produce burst pulse sounds. Proceedings. Biological sciences / The Royal Society. PMID: 15101430
Highlights from the forthcoming tech fest SIGGRAPH Asia 2011
1) An Iphone app that writes your autobiography from internet posts
2) A Cartography graphics tool for cardiologists
3) A Renaissance collage generator.
Plus a video of some great rendering software innovations.... Read more »
Zhu, B., Iwata, M., Haraguchi, R., Ashihara, T., Umetani, N., Igarashi, T., & Nakazawa, K. (2011) Sketch-based Dynamic Illustration of Fluid Systems. ACM Transactions on Graphics, 30(6), 1. DOI: 10.1145/2070781.2024168
This week I am attending the Materials Research Society Fall meeting in Boston, where there is a big focus on energy. Catalysis, fuel cells, batteries, solar cells, solar fuel, you name it. And I had a discussion with some researchers from the inorganic solar cell community, who asked me what is with the organic solar cells? [...]... Read more »
Since the science world is abuzz with news of experiments detecting neutrinos making a 732 kilometer trip in record time, 60 nanoseconds ahead of light itself, I have two questions. First is how big of a speeding ticket to give the neutrinos in question, and second is whether these neutrinos could now go back in [...]... Read more »
Cohen, A., & Glashow, S. (2011) Pair Creation Constrains Superluminal Neutrino Propagation. Physical Review Letters, 107(18). DOI: 10.1103/PhysRevLett.107.181803
On Nov. 26, 2011 at 10:02 AM EST the Mars Science Laboratory (MSL) launched successfully from Cape Canaveral using Atlas V 541 rocket and began its journey to Mars. MSL carries the biggest and the most robust Mars rover ever built.... Read more »
Golombek, et al. (2004) Surfical geology of the Spirit rover traverse in Gusev Crater: dry and desiccating since the Hesperian. Second Conference on Early Mars . info:/
Squyres SW, Arvidson RE, Bell JF 3rd, Brückner J, Cabrol NA, Calvin W, Carr MH, Christensen PR, Clark BC, Crumpler L.... (2004) The Opportunity Rover's Athena science investigation at Meridiani Planum, Mars. Science (New York, N.Y.), 306(5702), 1698-703. PMID: 15576602
Sallé, B., Lacour, J., Mauchien, P., Fichet, P., Maurice, S., & Manhès, G. (2006) Comparative study of different methodologies for quantitative rock analysis by Laser-Induced Breakdown Spectroscopy in a simulated Martian atmosphere. Spectrochimica Acta Part B: Atomic Spectroscopy, 61(3), 301-313. DOI: 10.1016/j.sab.2006.02.003
Although it would be nice to hatch our babies from eggs Anne Geddes-style, or deliver them while still tiny and carry them around in a pouch, humans and other placental mammals are stuck lugging their developing fetuses inside their bodies. Luckily, most humans aren't in danger of predation. But for animals that sometimes have to run (or swim) for their lives, pregnancy can be dangerous.
In a punnily titled new study ("Pregnancy is a drag"), UC Santa Cruz researcher Shawn Noren investigates how pregnant dolphins are affected by carrying a wide load. Noren studied two captive bottlenose dolphins, each about 10 days away from giving birth, living in a lagoon in Hawaii.
Though the study only included these two dolphins, Noren collected many data points by having a scuba diver sit underwater and videotape the dolphins swimming back and forth. The dolphins were also observed and recorded periodically during the two years after they gave birth. By digitizing these videos, the researchers could quantify the dolphins' size, mass, surface area, swimming speed, and swimming mechanics.
As expected, very pregnant dolphins had a very much larger surface area. This created greater drag as the dolphins glided through the water. The dolphins also changed their swimming "gait," like a human who finds herself a little waddle-y in the final trimester. Dolphins get all their forward thrust from the up-and-down beats of their tails. The pregnant dolphins beat their tails a little more shallowly than usual, maybe because their muscles were stretched out and weakened by the fetus (or because their midsections were less flexible). Just like a human taking smaller steps, a dolphin making smaller tail-beats covers less distance. So the pregnant dolphins had to beat their tails faster to maintain a given speed.
Besides experiencing greater drag and a shortened "stride," pregnant dolphins have altered blood flow and lower lung capacity. They also store more lipid (fat) than usual in their blubber, making them extra buoyant. All these factors combine to slow a dolphin way, way down. The two pregnant dolphins in the study swam more than 60% slower, on average, before their calves were born. After recovering from pregnancy, the dolphins' average swimming speed was around 9 mph. But before giving birth, their speed was closer to 3.5 mph--similar to the pace of a walking human.
The crucial factor in avoiding predators such as sharks, though, is maximum speed. After pregnancy, the dolphins reached maximum swimming speeds of more than 14 mph. While heavily pregnant, they barely reached 8 mph. Of course, the researchers didn't introduce any sharks or killer whales into the lagoon to see how fast the dolphins could swim under real duress. But the researchers note that at the fastest swimming speeds they observed, pregnant dolphins would not have been able to out-swim most predators.
It's unknown whether pregnant dolphins are more vulnerable to predators in the wild. But among ungulates--hoofed mammals such as buffalo or wildebeest, which happen to be close relatives of whales and dolphins--pregnancy is a known risk factor for being eaten by lions. In dolphins, the greater effort needed to swim while pregnant probably means they need to take in more calories. But it also must make hunting for food more difficult. A pregnant dolphin will have a harder time chasing after quick prey or, because of her increased buoyancy, diving to hunt.
In humans, studies of how pregnancy affects walking have been inconclusive. This might be because there's a great deal of variation in how individuals' bodies adjust to pregnancy. These two dolphins, too, may not be representative of their whole species. But they demonstrate the amazing adaptability of a female mammal's body, whether she's diving for squid or just shuffling through the suburbs.
Image: Shawn Noren/JEB
Noren, S., Redfern, J., & Edwards, E. (2011). Pregnancy is a drag: hydrodynamics, kinematics and performance in pre- and post-parturition bottlenose dolphins (Tursiops truncatus) Journal of Experimental Biology, 214 (24), 4151-4159 DOI: 10.1242/jeb.059121
... Read more »
Noren, S., Redfern, J., & Edwards, E. (2011) Pregnancy is a drag: hydrodynamics, kinematics and performance in pre- and post-parturition bottlenose dolphins (Tursiops truncatus). Journal of Experimental Biology, 214(24), 4151-4159. DOI: 10.1242/jeb.059121
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