Slashdot Mirror

Kristina at Science News writes "A new way to process images reveals an extrasolar planet that had been hiding in an 11-year-old Hubble picture. After ground-based telescopes found three planets orbiting the young star HR 8799, a team took that information and reprocessed some 11-year-old Hubble Space Telescope images. Voila. There was one of the three planets, captured by Hubble but not visible until new knowledge could see the picture in a fresh light. The technique could reveal hidden treasures in many archived telescope images." For reference, the first exoplanet to be (knowingly) directly imaged was 2M1207_b in late 2004.

Science News has an article on research into a compound found in a particular kind of sea sponge that seems to have the ability to restore antibiotics' effectiveness against resistant bacteria. The hope is that, since the compound is not itself deadly or even harmful to bacteria, it may skew the antibiotic-bacteria arms race in our favor. "Chemical analyses of the sponge's chemical defense factory pointed to a compound called algeferin. Biofilms, communities of bacteria notoriously resistant to antibiotics, dissolved when treated with fragments of the algeferin molecule. And new biofilms did not form. So far, the algeferin offshoot has, in the lab, successfully treated bacteria that cause whooping cough, ear infections, septicemia and food poisoning. The compound also works on... [MRSA] infections, which wreak havoc in hospitals. 'We have yet to find one that doesn't work,' says [one of the researchers]."

Science News reports on a new study which found that the violence in video games was not a significant contributing factor to players' enjoyment. Instead, the feelings of control and competence the games engendered were closely linked to how fun the players found it. Quoting: "... the researchers extensively modified a popular first-person shooter video game called Half-Life 2 to have less gore. Half the people in a group of 36 male and 65 female college students were instructed to dispatch adversaries as the original game intended, 'in a thoroughly bloody manner,' says Ryan. The other half was instructed to tag enemies with a marker. 'Instead of exploding in blood and dismemberment, they floated gently into the air and went back to base,' Ryan describes. An extensive survey of the two groups showed that the exclusion of violence didn't diminish players' enjoyment of the game."

erickhill writes with word that scientists from the University of Maryland have successfully transferred information from one charged atom to another without having it cross the intervening space of about one meter. The academic paper is available in the journal Science, though it requires a subscription to see more than the abstract. Scientists have previously teleported unmolested qubits between photons of light, and between photons and clouds of atoms. But researchers have long sought to teleport qubits between distant atoms. Light's high speed of travel makes photons good transporters of information, but for storing quantum information, atoms are a much better choice because they're easier to hold on to. 'This is a big deal,' comments Myungshik Kim, a quantum physicist at Queen's University Belfast in the United Kingdom. 'To store information as it is in quantum form, you have to have a teleportation scheme available between two stationary qubits. Then you can store them and manipulate them later on.'"

Science News has a fascinating look at an under-appreciated corner of the career of Florence Nightingale — as an innovator in the use of statistical graphics to argue for social change. Nightingale returned from the Crimean War a heroine in the eyes of the British citizenry, for the soldiers' lives she had saved. But she came to appreciate that the way to save far more lives was to reform attitudes in the military about sanitation. Under the tutelage of William Farr, who had just invented the field of medical statistics, she compiled overwhelming evidence (in the form of an 830-page report) of the need for change. "As impressive as her statistics were, Nightingale worried that Queen Victoria's eyes would glaze over as she scanned the tables. So Nightingale devised clever ways of presenting the information in charts. Statistics had been presented using graphics only a few times previously, and perhaps never to persuade people of the need for social change."

An anonymous reader writes "Mathematical proofs are supposed to establish absolute certainty, since each statement is a pure deduction from fundamental axioms. But the reality is that mathematicians make mistakes. Proof-validation software can do what mathematicians never do: spell out every last step, making sure everything is right. Such software has been around for 20 years, but mathematicians and computer scientists now say they are nearing the point where every mathematician will routinely use the software before submitting a new result to a journal, producing a fully correct, formal, axiomatized mathematics."

An anonymous reader writes "You may have heard that it takes about seven shuffles to mix up a deck of cards to near randomness. Turns out, though, that most of the time, perfect randomness is more than you need. In blackjack, for example, you don't care about suits. The same mathematician who developed the original result now says that for many games, four shuffles is enough. And the result isn't only important for card sharks. It helps reveal the math underlying Markov Chain Monte Carlo simulations, telling applied mathematicians when they can stop their simulations."

dooling writes "A paper detailing the sequencing of the first human cancer genome will be published in the 6 November 2008 issue of Nature. This is not only the first cancer genome published, it is the first female genome as well. You can read the paper's abstract, DNA sequencing of a cytogenetically normal acute myeloid leukaemia genome, or the story in Science News. This issue of Nature also has articles on the sequencing of the first African and Asian genomes. The sequencing in all three articles was done using the Illumina Genome Analyzer, one of the massively parallel, next-generation genome sequencing platforms."

An anonymous reader sends us to Science News, which is running a survey of recent strides in finding an answer to the age-old question: How many ways are there to tie your shoelaces? "Mathematicians have been puzzling over that question for a century or two, and the main thing they've discovered is that the question is really, really hard. In the last decade, though, they've developed some powerful new tools inspired by physics that have pried a few answers from the universe's clutches. Even more exciting is that the new tools seem to be the tip of a much larger theory that mathematicians are just beginning to uncover. That larger mathematical theory, if it exists, may help crack some of the hardest mathematical questions there are, questions about the mathematical structure of the three- and four-dimensional space where we live. ... Revealing the full ... superstructure may be the work of a generation."

xyz writes "Do black holes increase in size indefinitely? According to an analysis by astronomers at Yale and the European Southern Observatory, the maximum size a black hole may reach is only few tens of billion of solar masses. The limit was calculated using an analysis of what may happen to the gas surrounding a black hole which has reached few tens of billions of solar masses. It is thought that black holes of such size heat the surrounding gas to a temperature where the radiation pressure begins blowing outer layers into space."

monk writes "Science News references a story in the October 10 Science about Cambrian invertebrates which formed weird permanent chains up to twenty individuals long. 'The discovery of 525-million-year-old fossils belonging to a new species of arthropod shows that these animals formed communal chains never before seen in fossilized invertebrates.' It should be obvious to any Slashdotter of a certain age that this is the true origin of the so called 'centipede' in the eponymous game."

An anonymous reader writes "US News makes a mint off its college rankings every year, but do they really give meaningful information? A pair of mathematicians argues that the data the magazine uses is all likely to be at least somewhat relevant, but that the way the magazine weights the different statistics is pretty arbitrary. After all, different people may have different priorities. So they developed a method to compute the rankings based on any possible set of priorities. To do it, they had to reverse-engineer some of US News's data. What they found was that some colleges come out on top pretty much regardless of the prioritization, but others move around quite a lot. And the top-ranked university can vary tremendously. Penn State, which is #48 using US News's methodology, could be the best university in the country, by other standards."

Science News reports on a paper to be published in Physical Review Letters in which an international team of researchers describes their computer simulation of the most violent collision imaginable: two black holes colliding head-on at nearly light-speed. Even in this extreme scenario, Roger Penrose's weak cosmic censorship hypothesis seems to hold — the resulting black hole (after the gravitational waves have died down) retains its event horizon. "Mathematically, 'naked' singularities, or those without event horizons, can exist, but physicists wouldn't know what to make of them. All known mechanisms for the formation of singularities also create an event horizon, and Penrose conjectured that there must be some physical principle — a 'cosmic censor' — that forbids singularity nakedness ..."

roncosmos writes "Science News has up a feature on the first use of sound recording in a presidential campaign. In 1908, for the first time, presidential candidates recorded their voices on wax cylinders. Their voices could be brought into the home for 35 cents, equivalent to about $8 now. In that pre-radio era, this was the only way, short of hearing a speech at a whistle stop, that you could hear the candidates. The story includes audio recordings from the 1908 candidates, William Jennings Bryan and William Howard Taft. Bryan's speech, on bank failures, seems sadly prescient now. Taft's, on the progress of the Negro, sounds condescending to modern ears but was progressive at the time. There are great images from the campaign; lots of fun."

roncosmos writes "Science News has up a feature on the first use of sound recording in a presidential campaign. In 1908, for the first time, presidential candidates recorded their voices on wax cylinders. Their voices could be brought into the home for 35 cents, equivalent to about $8 now. In that pre-radio era, this was the only way, short of hearing a speech at a whistle stop, that you could hear the candidates. The story includes audio recordings from the 1908 candidates, William Jennings Bryan and William Howard Taft. Bryan's speech, on bank failures, seems sadly prescient now. Taft's, on the progress of the Negro, sounds condescending to modern ears but was progressive at the time. There are great images from the campaign; lots of fun."

An anonymous reader writes "Science News reports on a new study showing that most cancer drug trial results are never published, probably leaving patients vulnerable to cocktails that have already been shown to be dangerous or useless."

Kristina from Science News writes "Combining computer simulations with data about the way starlight shines through Saturn's rings suggests the individual grains are big and thus could have been around a good 4 billion years, not the mere 10 million to 100 million previously suspected. What may have thrown earlier observations off is the chance that the grains aren't evenly distributed, but clump here and spread out there."

Kristina from Science News writes "Combining computer simulations with data about the way starlight shines through Saturn's rings suggests the individual grains are big and thus could have been around a good 4 billion years, not the mere 10 million to 100 million previously suspected. What may have thrown earlier observations off is the chance that the grains aren't evenly distributed, but clump here and spread out there."

Several readers including houbou and DigitumDei sent links to what may be the first-ever image of a planet orbiting a sun-like star (research paper). The giant planet, the mass of 8 Jupiters, orbits its star at 330 AU, or 11 times the distance to Neptune's orbit. If the imaged object does turn out to be a planet — and it's not certain it is — then theories of planet formation may have to be adjusted. "The bulk of the material from which planets might form is significantly closer to the parent star... The outermost parts of such disks wouldn't contain enough material to assemble a Jupiter-mass planet at the distance from the star... at which the Toronto team found the faint object."

ColGraff points out reporting at Science News about the possibility of killing bacteria with paint. Scientists in the UK have found that high concentrations of titanium oxide nanoparticles in paint can kill bacteria by creating hydroxyl radicals when exposed to ordinary fluorescent light. Titanium dioxide is present in most white paint at concentrations of 30% or so, but not always at nanoparticle scale. The researchers found that an 80% concentration of TiO2 nanoparticles worked well to kill E. Coli bacteria. There is hope that the technique could be used against "superbugs," which are resistant to multiple antibiotics. A researcher not associated with the UK team pointed out the problem with developing products based on this idea: "[A]nything that survives and sticks around grows greater resistance... ultimately [antibiotic paint] will be its own worst enemy and the bacteria could grow to be even stronger."

thedreadedwiccan points out a summary of a recently released physics paper about tying knots with light. A pair of researchers showed that a relatively new solution to Maxwell's equations allows light to be twisted into stable loops. They are designing experiments to test the theory now, and it could have a big impact on fusion technology. The paper's abstract is available at Nature, though a subscription is required to see the rest. Quoting: "In special situations, however, the loops might be stable, such as if light travels through plasma instead of through free space. One of the problems that has plagued experimental nuclear fusion reactors is that the plasma at the heart of them moves faster and faster and tends to escape. That motion can be controlled with magnetic fields, but current methods to generate those fields still don't do the job. If Irvine and Bouwmeester's discovery could be used to generate fields that would send the plasma in closed, non-expanding loops and help contain it, 'that would be extremely spectacular,' Bouwmeester says."

Anti-Globalism suggests an article at Science News on the passing of Henri Cartan, one of the founding members of a strange and influential group of French mathematicians in the twentieth century. "In the 1930s, a group of young French mathematicians led an uprising that revolutionized mathematics. France had lost most of a generation in the First World War, so the emerging hotshots in mathematics had few elders to look up to. And when these radicals did look up, they didn't like what they saw. The practice of mathematics at the time was dry, scattered and muddled, they believed, in need of reinvention and invigoration... Using the nom de plume Nicolas Bourbaki (after a dead Napoleonic general), they wrote a series of textbooks laying out mathematics the right way. Though the young mathematicians started out only intending to write a good textbook for analysis..., they ended up creating dozens of volumes which formed a manifesto for a new philosophy of mathematics. The last of the founders of Bourbaki, Henri Cartan, died August 13 at age 104... Two of his students won the Fields medal..., one won the Nobel Prize in physics and another won the economics Nobel."

SpuriousLogic alerts us to the discovery of what may be the first object ever discovered from the inner edge of the Oort cloud. 2006 SQ372 was found on images from the Sloan Digital Sky Survey. Its discoverers theorize that this comet-like object and the planetoid Sedna, first spotted in 2003, might be Oort denizens. Sedna is in a stable orbit but 2006 SQ372 has been perturbed by the gravity of Uranus and/or Neptune, simulations suggest, so its orbital history is unknowable. 2006 SQ372 will travel out to 1,600 AU on this orbit, making it the most distant solar-system object yet found. The Oort cloud is believed to extend ten times that far, or about a quarter of a light-year. "Theoretical models of the formation of the Oort Cloud predict that it should also host a massive inner part, but comets from this region never make it near Earth. To see the long-period comets from the inner region of the Oort Cloud requires observing comets whose orbits always stay well outside Saturn's orbit — like 2006 SQ372."

An anonymous reader writes "Think it's impossible to see four-dimensional objects? These videos will show you otherwise. Some mathematicians work with four-dimensional objects all the time, and they've developed some clever tricks to get a feeling for what they're like. The techniques begin by imagining how two-dimensional creatures, like those in Edwin Abbot's 'Flatland,' could get a feeling for three-dimensional objects. When those techniques are transferred up a dimension, the results are gorgeous."

A commonplace of cosmologists who argue the anthropic principle is the assumption that if any or a few of the constants of nature took on an even slightly different value, life could not have evolved — perhaps even stars and galaxies would not form. Science News reports on a new calculation showing that, to the contrary, star formation could happen in up to one-quarter of universes with different values of three important constants. "In fact, all universes can support the existence of stars, provided that the definition of star is interpreted broadly," said the researcher, Fred Adams. "...calculations suggest that, contrary to some previous claims, stars are not only common in our cosmos but are also ablaze in myriad other universes, where the laws of physics may be drastically different... Had Adams found that the range of parameters that allowed for stars was very small, that would have suggested that the laws of physics in our universe have been 'fine-tuned' to allow for star formation... Instead, Adams' study shows that our universe doesn't seem particularly special in that regard."

An anonymous reader sends in a Science News article that begins: "Human free will might seem like the squishiest of philosophical subjects, way beyond the realm of mathematical demonstration. But two highly regarded Princeton mathematicians, John Conway and Simon Kochen, claim to have proven that if humans have even the tiniest amount of free will, then atoms themselves must also behave unpredictably." Standard interpretations of quantum mechanics, of course, embrace unpredictability. But many physicists aren't comfortable with that, and are working to develop deterministic interpretations of quantum mechanics. Conway and Kochen's proof argues that these efforts will be fruitless — unless one is willing to give up human free will, in a very strong sense. The article quotes Conway: "We can really prove that there's no algorithm, no way that the particle can give an answer that is unique and can be specified ahead of time. I'm still amazed that we can actually manage to prove that."

A team of researchers has simulated the gravitational interaction of dark matter particles over the course of a hypothetical 13.7 billion years. They found that the particles tended to form clumps large enough to assist in the formation of galaxies. The results contradicted observations from previous, smaller studies, but they lent support to an unrelated simulation of how the Milky Way formed. UCSC's press release is also available. Quoting ScienceNews: "The clumps of dark matter in the simulation have densities that are remarkably similar to densities that a University of California, Irvine research group found when simulating the formation of the Milky Way and its satellite dwarf galaxies, says James Bullock, the astrophysicist who leads the UC-Irvine group and was not involved in the new study. 'This is a remarkable success of the particular model simulated and adds strong support to the idea that the dark matter is made up of particles that are "cold." There are a number of planned experiments aimed at detecting the dark matter that are betting on it being cold, so this is generally good news for the community,' Bullock says. And, [study co-author Piero Madau] notes, larger simulations that might help constrain the nature of dark matter even more are already in the works."

An anonymous reader sends along a link to a mindbending article in Science News on quasicrystals — odd materials with a structure partway between order and disorder. Now researchers have found something even odder: a material that's partway between a quasicrystal and a regular crystal. The order in the new structure is provided by the Fibonacci sequence. It was constructed with plastic beads and laser beams, so no new materials science inventions are on the horizon. "'We are absolutely sure that this structure should have properties that are not usual,' Mikhael says, because materials with odd structures almost always do. Now they just have to figure out what those properties are."

Science News has a look at the latest paleontological fashion: what may be the remains of pigment in fossilized feathers 100 million years old. The material in question is believed to be black melanin, on the evidence of its similarity in scanning-microscope images to the modern pigment. The researchers are hopeful of identifying other varieties of melanin, which provide red or yellow coloration; and also possibly of spotting fossilized nanostructures of melanin that create iridescent patterns in some modern animals.

An anonymous reader writes "Researchers have found that the long-held belief that only the outer, valence, electrons of an atom interact may be false. Computer simulations have shown that at pressures like those in the center of the Earth the inner, core, electrons of lithium also interact."

Science News has a story of strange bedfellows. It seems that Antarctica was once adjacent to what is now the American Southwest, some 800 million years ago. Earth's continents then formed a supercontinent called Rodinia, predating Pangaea by some 550 million years. "...the ratios of neodymium isotopes in the ancient sediments in the Transantarctic Mountains are the same as those in what was then Laurentia, says Goodge. Also, the hafnium isotope ratios in the 1.44-billion-year-old zircons found in East Antarctica match those of the zircons found in the distinctive granites now found primarily in North America. Finally, the researchers note, the ratios of various isotopes and elements in a basketball-sized chunk of granite found in East Antarctica — a chunk ripped by a glacier from bedrock now smothered by thick ice, the team speculates — match those of granite found only in what was southwestern Laurentia, which today is the American Southwest."

Science News reports on research suggesting that humans' language ability may have developed earlier than we thought. Scientists used CT scanning of H. heidelbergensis skulls, more than 530,000 years old, to reconstruct the structure of the ear canal of this Neanderthal ancestor. They found evidence that the ears of these early hominids would have had a sensitivity peak in the same 2-4 KHz range that the ears of modern humans do — the range in which most information is carried in language. Sensory systems are neurologically expensive, and it's unlikely that the body would invest the resources in maintaining such a system if it didn't serve a purpose. Quoting: "It may be time to rethink the stereotype of grunting, wordless Neanderthals. The prehistoric humans may have been quite chatty — at least if the ear canals of their ancestors are any indication. The findings suggest human speech may have originated earlier than some researchers contend. Anthropologists disagree about whether language sprang up rapidly around 50,000 years ago or emerged more gradually over a longer period of time..."

We discussed the Galaxy Zoo project soon after it launched last summer. Science News is now following developments about an odd celestial object that is fueling a lot of excitement among astronomers around the world. In August, a Dutch schoolteacher named Hanny, in the process of characterizing galaxy images, noticed a peculiar object and posted a query about it on the Galaxy Zoo blog. She called it a "Voorwerp," which Science News says is Dutch for "thing" but which Google translates as "subject." Hanny's Voorwerp emits mostly green light (the earlier report said blue). The best guess astronomers have now is that the Voorwerp is emitting "ghost light," i.e. it is "lit by the ultraviolet light and X-rays from a quasar that has vanished in the last 100,000 years," to quote astronomer Bill Keel. "As far as we can tell, it's an unprecedented thing," Keel added. Researchers are scrambling to book time on the Hubble and other major telescopes to get a closer look.

We discussed the Galaxy Zoo project soon after it launched last summer. Science News is now following developments about an odd celestial object that is fueling a lot of excitement among astronomers around the world. In August, a Dutch schoolteacher named Hanny, in the process of characterizing galaxy images, noticed a peculiar object and posted a query about it on the Galaxy Zoo blog. She called it a "Voorwerp," which Science News says is Dutch for "thing" but which Google translates as "subject." Hanny's Voorwerp emits mostly green light (the earlier report said blue). The best guess astronomers have now is that the Voorwerp is emitting "ghost light," i.e. it is "lit by the ultraviolet light and X-rays from a quasar that has vanished in the last 100,000 years," to quote astronomer Bill Keel. "As far as we can tell, it's an unprecedented thing," Keel added. Researchers are scrambling to book time on the Hubble and other major telescopes to get a closer look.

We discussed the Galaxy Zoo project soon after it launched last summer. Science News is now following developments about an odd celestial object that is fueling a lot of excitement among astronomers around the world. In August, a Dutch schoolteacher named Hanny, in the process of characterizing galaxy images, noticed a peculiar object and posted a query about it on the Galaxy Zoo blog. She called it a "Voorwerp," which Science News says is Dutch for "thing" but which Google translates as "subject." Hanny's Voorwerp emits mostly green light (the earlier report said blue). The best guess astronomers have now is that the Voorwerp is emitting "ghost light," i.e. it is "lit by the ultraviolet light and X-rays from a quasar that has vanished in the last 100,000 years," to quote astronomer Bill Keel. "As far as we can tell, it's an unprecedented thing," Keel added. Researchers are scrambling to book time on the Hubble and other major telescopes to get a closer look.

An anonymous reader recommends a ScienceNews story that begins: "Dmitry Khavinson and Genevra Neumann didn't know anything about astrophysics. They were just doing mathematics, like they always do, following their curiosity. But five days after they posted one of their results on a preprint server, they got an email that said 'Congratulations! You've proven Sun Hong Rhie's astrophysics conjecture on gravitational lensing!'... Turns out that when gravity causes light rays to bend, it can make one star look like many. But until Khavinson and Nuemann's work, astrophysicists weren't sure just how many. Their proof in mathematics settled the question."

Science News reports on a study relating (in a loose way) the efficiency of a national government with the size of its cabinet. Researchers in Vienna found that the development level of countries, as a proxy for the efficiency of their governments, is in general lower for countries with more members in the national cabinets. They then went on to model cabinet members as nodes in a network and found support for the observed correlation. There was even specific evidence for the decades-old observation of English historian Cyril Northcote Parkinson that decision-making is severely impaired in committees of more than 20 people. The US is getting close to Parkinson's cutoff, at 17.

Science News reports on recent research indicating that any kind of multitasking while driving is dangerous. Not just the obvious distraction of juggling a cell phone, but even talking to a passenger or listening to a book on tape. The researchers used a driving simulator inside an MRI machine to measure brain activations. "Attending to what someone says galvanizes language-related brain areas while simultaneously reducing activity in spatial regions that coordinate driving behavior. This finding suggests that people who combine relatively automatic tasks, such as speech comprehension and car driving, exceed a biological limit on the amount of systematic brain activity they can accommodate at one time, the researchers propose. As a result, the less-ingrained skill — in this case, driving, which is learned long after a person grasps a native language — takes a neural hit."

An anonymous reader points out an article up at Science News on a question that, remarkably, is still being debated after a few thousand years: is mathematics discovered, or is it invented? Those who answer "discovered" are the intellectual descendants of Plato; their number includes Roger Penrose. The article notes that one difficulty with the Platonic view: if mathematical ideas exist in some way independent of humans or minds, then human minds engaged in doing mathematics must somehow be able to connect with this non-physical state. The European Mathematical Society recently devoted space to the debate. One of the papers, Let Platonism die, can be found on page 24 of this PDF. The author believes that Platonism "has more in common with mystical religions than with modern science."

Euler points out a story about art created through mathematics. The Science News article covers selections from a recent exhibit, where over 40 artists gathered to show their work and the math behind it. The rest of the pieces are also viewable at the exhibit's website. "Michael Field, a mathematics professor at the University of Houston, finds artistic inspiration in his work on dynamical systems. A mathematical dynamical system is just any rule that determines how a point moves around a plane. Field uses an equation that takes any point on a piece of paper and moves it to a different spot. Field repeats this process over and over again--around 5 billion times--and keeps track of how often each pixel-sized spot in the plane gets landed on. The more often a pixel gets hit, the deeper the shade Field colors it."

An anonymous reader writes "A mathematician will receive a Grammy award for restoring the only known recording of a live Woody Guthrie performance — a bootleg someone made in 1949 using a wire recorder. Guthrie's daughter, who had never heard her father perform in front of a live audience, oversaw the restoration. The article links very cool before and after clips."

An anonymous reader writes "A mathematician will receive a Grammy award for restoring the only known recording of a live Woody Guthrie performance — a bootleg someone made in 1949 using a wire recorder. Guthrie's daughter, who had never heard her father perform in front of a live audience, oversaw the restoration. The article links very cool before and after clips."

An anonymous reader writes "A mathematician will receive a Grammy award for restoring the only known recording of a live Woody Guthrie performance — a bootleg someone made in 1949 using a wire recorder. Guthrie's daughter, who had never heard her father perform in front of a live audience, oversaw the restoration. The article links very cool before and after clips."

palegray.net writes "Scientists believe they have found the underlying reasons why knots are so common in the universe. This research helps us understand how knotty arrangements in various molecules lead to biological patterns, as in certain proteins. The article also provides a look at the field of topology, and how it relates to knots."

ianare writes "Eight tusks and a bison skull all show signs of having being blasted with iron-nickel fragments, typical meteorite material. Raised, burnt surface rings trace the point of entry of high-velocity projectiles; and the punctures are on only one side, consistent with a blast coming from a single direction. But the team was astonished to find the animal remains were about 35,000 years old, rather than from the known impact of 13,000 years ago."

DurandalTree writes "With the spectre of global warming on the horizon, biofuels have been touted as the solution to motor vehicles' greenhouse gas emissions. But with biodiesel use on the increase, it appears a distinctively environmentally unfriendly footprint is being left behind by some of its prime sources; affected food prices are surging out of reach of the poor and rainforests are being destroyed to create larger plantations."

Ant writes "A Science News article talks about the relationship between city design and health. New cross-disciplinary research is exploring whether urban sprawl makes us soft, or whether people who don't like to exercise move to the sprawling suburbs, or some combination of both." From the article: "So far, the dozen strong studies that have probed the relationships among the urban environment, people's activity, and obesity have all agreed, says Ewing. 'Sprawling places have heavier people... There is evidence of an association between the built environment and obesity.' ... However, University of Toronto economist Matthew Turner charges that 'a lot of people out there don't like urban sprawl, and those people are trying to hijack the obesity epidemic to further the smart-growth agenda [and] change how cities look.' ... 'We're the only ones that have tried to distinguish between causation and sorting... and we find that it's sorting,' [says Turner]. 'The available facts do not support the conclusion that sprawling neighborhoods cause weight gain.'"

duguk writes in with another reason to keep happy over Christmas. A new scientific study suggests that people who frequently experience positive emotions are less likely to catch colds. Psychologist Sheldon Cohen and his colleagues at Carnegie Mellon University interviewed 193 healthy adults daily for two weeks and recorded the positive and negative emotions they had experienced each day. The researchers then exposed the volunteers to a cold or a flu virus. Those with "generally positive outlooks" reported fewer cold symptoms. From the article: "'We need to take more seriously the possibility that a positive emotional style is a major player in disease risk,' Cohen says... Although a positive emotional style bore no relation to whether participants became infected, it protected against the emergence of cold symptoms. For instance, among people infected by the influenza virus... 28 percent who often reported positive emotions developed coughs, congestion, and other cold symptoms, as compared with... 41 percent who rarely reported positive emotions."

FleaPlus writes "Physicists in England and the Netherlands have unveiled a technique for constructing rigid DNA pyramids. With the technique, trillions of d4's can rapidly self-assemble from a solution of single-stranded DNA. The scientists also showed that single DNA strands called linkers could be used to attach the tetrahedra to each other, acting as a possible building block for 3D nanofabrication."

Steve Nixon writes "Recently, a team of scientists devised a way to make single-celled algae bear loads over distances of several centimeters--a tactic that the researchers say could prove useful in tiny machines. Algae and other single-celled organisms power their movements with molecular motors. 'Scientists have long coveted these motors for use in micromachinery,' notes chemist Douglas B. Weibel of Harvard University.