Things tagged science:
Can a Jellyfish Unlock the Secret of Immortality?
Nathaniel Rich in the NYT Magazine:
Sommer was conducting research on hydrozoans, small invertebrates that, depending on their stage in the life cycle, resemble either a jellyfish or a soft coral. Every morning, Sommer went snorkeling in the turquoise water off the cliffs of Portofino. He scanned the ocean floor for hydrozoans, gathering them with plankton nets. Among the hundreds of organisms he collected was a tiny, relatively obscure species known to biologists as Turritopsis dohrnii. Today it is more commonly known as the immortal jellyfish.
Sommer kept his hydrozoans in petri dishes and observed their reproduction habits. After several days he noticed that his Turritopsis dohrnii was behaving in a very peculiar manner, for which he could hypothesize no earthly explanation. Plainly speaking, it refused to die. It appeared to age in reverse, growing younger and younger until it reached its earliest stage of development, at which point it began its life cycle anew.
The Heretic
Tim Doody in The Morning News:
For decades, the U.S. government banned medical studies of the effects of LSD. But for one longtime, elite researcher, the promise of mind-blowing revelations was just too tempting.
Studies of Human Microbiome Yield New Insights
Carl Zimmer in the NYT:
For a century, doctors have waged war against bacteria, using antibiotics as their weapons. But that relationship is changing as scientists become more familiar with the 100 trillion microbes that call us home — collectively known as the microbiome.
“I would like to lose the language of warfare,” said Julie Segre, a senior investigator at the National Human Genome Research Institute. “It does a disservice to all the bacteria that have co-evolved with us and are maintaining the health of our bodies.”
This new approach to health is known as medical ecology. Rather than conducting indiscriminate slaughter, Dr. Segre and like-minded scientists want to be microbial wildlife managers.
Hearts Beat as One During a Fire-Walking Ritual
Pam Belluck in the NYT:
The results surprised them. The heart rates of relatives and friends of the fire-walkers followed an almost identical pattern to the fire-walkers’ rates, spiking and dropping almost in synchrony. The heart rates of visiting spectators did not. The relatives’ rates synchronized throughout the event, which lasted 30 minutes, with 28 fire-walkers each making five-second walks. So relatives or friends’ heart rates matched a fire-walker’s rate before, during and after his walk. Even people related to other fire-walkers showed similar patterns.
Experts not involved in the study said despite the small number of participants, the results were intriguing. They build on research showing heart rates of fans of team sports surge when their teams score, and on studies demonstrating that people rocking in rocking chairs or tapping their fingers eventually synchronize their movements.
Secrets of the Phallus: Why Is the Penis Shaped Like That?
In SciAm:
If you’ve ever had a good, long look at the human phallus, whether yours or someone else’s, you’ve probably scratched your head over such a peculiarly shaped device. Let’s face it—it’s not the most intuitively shaped appendage in all of evolution. But according to evolutionary psychologist Gordon Gallup of the State University of New York at Albany, the human penis is actually an impressive “tool” in the truest sense of the word, one manufactured by nature over hundreds of thousands of years of human evolution. You may be surprised to discover just how highly specialized a tool it is. Furthermore, you’d be amazed at what its appearance can tell us about the nature of our sexuality.
Via William Gibson.
Weapons of Mass Destruction
“Little Boy” (Hiroshima Atomic Bomb) 1945
Nice set of black and white (and infrared?) photos of cold war era Weapons of Mass Destruction.
See also: “Atomic John” in The New Yorker
The single, blinding release of pure energy over Hiroshima, Japan, on August 6, 1945, marked a startling and permanent break with our prior understandings of the visible world. Yet for more than sixty years the technology behind the explosion has remained a state secret.
The most accurate account of the bomb’s inner workings—an unnervingly detailed reconstruction, based on old photographs and documents—has been written by a sixty-one-year-old truck driver from Waukesha, Wisconsin, named John Coster-Mullen, who was once a commercial photographer, and has never received a college degree.
Earth, observed
The Earth Observatory is a website run by NASA’s Earth Observing System Project Science Office (EOSPSO). Bringing together imagery from many different satellites and astronaut missions, the website publishes fantastic images with highly detailed descriptions, feature articles and more. […] Gathered here are some standout photographs from the collections in the Earth Observatory over the past several years.
At The Big Picture.
An Engineering Evaluation of SHA-3 candidates
Niels [Ferguson, of the Skein team] has started a page of SHA-3 engineering comparisons.
Yes, they are biased, but I still trust the results.
Via Schneier on Security.
The evolution of homosexuality: Gender bending
The evidence suggests that homosexual behaviour is partly genetic. Studies of identical twins, for example, show that if one of a pair (regardless of sex) is homosexual, the other has a 50% chance of being so, too. That observation, though, raises a worrying evolutionary question: how could a trait so at odds with reproductive success survive the ruthless imperatives of natural selection?Various answers have been suggested. However, they all boil down to the idea that the relatives of those who are gay gain some advantage that allows genes predisposing people to homosexual behaviour to be passed on collaterally.One proposal is that the help provided by maiden aunts and bachelor uncles in caring and providing for the children of their brothers and sisters might suffice. That seems unlikely to be the whole story (the amount of help needed to compensate would be huge), though it might be a contributory factor.
The other idea, since there is evidence that male homosexuals, at least, are more likely than average to come from large families, is that the genes for gayness bring reproductive advantage to those who have them but are not actually gay themselves. Originally, the thought was that whichever genes make men gay might make women more fecund, and possibly vice versa.
Brendan Zietsch of the Queensland Institute of Medical Research in Brisbane, Australia, and his colleagues have, however, come up with a twist on this idea. In a paper to be published soon in Evolution and Human Behavior, they suggest the advantage accrues not to relatives of the opposite sex, but to those of the same one. They think that genes which cause men to be more feminine in appearance, outlook and behaviour and those that make women more masculine in those attributes, confer reproductive advantages as long as they do not push the individual possessing them all the way to homosexuality.
Click through for more at at The Economist.
Peering into the micro world
In this Harvard University photograph released October 8th, 2008, brain cells of a laboratory mouse are shown glowing with multicolor fluorescent proteins at Harvard University in Cambridge, Mass. The Nobel prize in chemistry was awarded to two Americans and a U.S.-based Japanese scientist for research on a glowing jellyfish protein that revolutionized the ability to study disease and normal development in living organisms. (AP Photo/Harvard University, Livett-Weissman-Sanes-Lichtman)
Posted at The Big Picture.
Scenes from Antarctica
Down in Antarctica, November marks the end of spring, the beginning of austral summer, and the beginning of Antarctica’s cruise season. The Sun just rose for the first time in 6 months on September 22nd, and is now visible in the sky all the time. Recent studies in Antarctica have brought new insights into the origins of deep sea octopus species (a 30 million-year-old ancestor from Antarctic waters), volcanic contributions to disappearing antarctic ice, and the effects of increasing numbers of icebergs scouring the seafloor. Collected here are 32 photographs of Antarctica from the past several years.
Posted at The Big Picture.
Sleep on It: How Snoozing Makes You Smarter
Robert Stickgold and Jeffrey M. Ellenbogen in Scientific American Mind
In 2007 one of us (Ellenbogen) showed that the brain learns while we are asleep. The study used a transitive inference task; for example, if Bill is older than Carol and Carol is older than Pierre, the laws of transitivity make it clear that Bill is older than Pierre. Making this inference requires stitching those two fragments of information together. People and animals tend to make these transitive inferences without much conscious thought, and the ability to do so serves as an enormously helpful cognitive skill: we discover new information (Bill is older than Pierre) without ever learning it directly.
The inference seems obvious in Bill and Pierre’s case, but in the experiment, we used abstract colored shapes that have no intuitive relation to one another, making the task more challenging. We taught people so-called premise pairs—they learned to choose, for example, the orange oval over the turquoise one, turquoise over green, green over paisley, and so on. The premise pairs imply a hierarchy—if orange is a better choice than turquoise and turquoise is preferred to green, then orange should win over green. But when we tested the subjects on these novel pairings 20 minutes after they learned the premise pairs, they had not yet discovered these hidden relations. They chose green just as often as they chose orange, performing no better than chance.
When we tested subjects 12 hours later on the same day, however, they made the correct choice 70 percent of the time. Simply allowing time to pass enabled the brain to calculate and learn these transitive inferences. And people who slept during the 12 hours performed significantly better, linking the most distant pairs (such as orange versus paisley) with 90 percent accuracy. So it seems the brain needs time after we learn information to process it, connecting the dots, so to speak—and sleep provides the maximum benefit.
Via Arts & Letters Daily.
Richard Feynman and the Connection Machine
W. Daniel Hillis for Physics Today at The Long Now Foundation:
One day when I was having lunch with Richard Feynman, I mentioned to him that I was planning to start a company to build a parallel computer with a million processors. His reaction was unequivocal, "That is positively the dopiest idea I ever heard." For Richard a crazy idea was an opportunity to either prove it wrong or prove it right. Either way, he was interested. By the end of lunch he had agreed to spend the summer working at the company.
Via Daring Fireball.
Could an Acid Trip Cure Your OCD?
Linda Marsa in Discover Magazine:
At a handful of sites across the country, after a four-decade hiatus, psychedelic research is undergoing a quiet renaissance, thanks to scientists like Charles Grob who are revisiting the powerful mind-altering drugs of the 1960s in hopes of making them part of our therapeutic arsenal. Hallucinogens such as psilocybin, MDMA (better known as Ecstasy), and the most controversial of them all, LSD, are being tested as treatments for maladies that modern medicine has done little to assuage, such as post-traumatic stress disorder, drug dependency, obsessive-compulsive disorder, cluster headaches, and the emotional suffering of people with a terminal illness.
While Grob’s study is not complete—he has tested 11 out of a projected 12 volunteers—patients seemed to have positive experiences. “No one had a bad trip, and most derived some benefit,” he says. “It lowered their anxiety, improved their mood and disposition, and imbued them with a greater acceptance of their situation and capacity to live in the moment and appreciate each day.”
This is a fairly well written article that covers the basics of past psychedelics research, and the current minimal studies that are going on now. I have archived the article here because Discover's site is completely broken in Safari, and hideously unusable in Firefox.
Does Time Run Backward in Other Universes?
A different theory than the earlier posted Loop Quantum Gravity ("quantum bounce"), though this article does touch on that idea in it's sum up of previous research.
Sean M. Carroll in Scientific American Magazine:
In the presence of dark energy, empty space is not completely empty. Fluctuations of quantum fields give rise to a very low temperature—enormously lower than the temperature of today’s universe but nonetheless not quite absolute zero. All quantum fields experience occasional thermal fluctuations in such a universe. That means it is not perfectly quiescent; if we wait long enough, individual particles and even substantial collections of particles will fluctuate into existence, only to once again disperse into the vacuum. (These are real particles, as opposed to the short-lived “virtual” particles that empty space contains even in the absence of dark energy.)
Among the things that can fluctuate into existence are small patches of ultradense dark energy. If conditions are just right, that patch can undergo inflation and pinch off to form a separate universe all its own—a baby universe. Our universe may be the offspring of some other universe.
Superficially, this scenario bears some resemblance to the standard account of inflation. There, too, we posit that a patch of ultradense dark energy arises by chance, igniting inflation. The difference is the nature of the starting conditions. In the standard account, the patch arose in a wildly fluctuating universe, in which the vast bulk of fluctuations produced nothing resembling inflation. It would seem to be much more likely for the universe to fluctuate straight into a hot big bang, bypassing the inflationary stage altogether. Indeed, as far as entropy is concerned, it would be even more likely for the universe to fluctuate straight into the configuration we see today, bypassing the past 14 billion years of cosmic evolution.
In our new scenario, the preexisting universe was never randomly fluctuating; it was in a very specific state: empty space. What this theory claims—and what remains to be proved—is that the most likely way to create universes like ours from such a preexisting state is to go through a period of inflation, rather than fluctuating there directly. Our universe, in other words, is a fluctuation but not a random one.
Emit fo Worra
This scenario, proposed in 2004 by Jennifer Chen of the University of Chicago and me, provides a provocative solution to the origin of time asymmetry in our observable universe: we see only a tiny patch of the big picture, and this larger arena is fully time-symmetric. Entropy can increase without limit through the creation of new baby universes.Best of all, this story can be told backward and forward in time. Imagine that we start with empty space at some particular moment and watch it evolve into the future and into the past. (It goes both ways because we are not presuming a unidirectional arrow of time.) Baby universes fluctuate into existence in both directions of time, eventually emptying out and giving birth to babies of their own. On ultralarge scales, such a multiverse would look statistically symmetric with respect to time—both the past and the future would feature new universes fluctuating into life and proliferating without bound. Each of them would experience an arrow of time, but half would have an arrow that was reversed with respect to that in the others.
The idea of a universe with a backward arrow of time might seem alarming. If we met someone from such a universe, would they remember the future? Happily, there is no danger of such a rendezvous. In the scenario we are describing, the only places where time seems to run backward are enormously far back in our past—long before our big bang. In between is a broad expanse of universe in which time does not seem to run at all; almost no matter exists, and entropy does not evolve. Any beings who lived in one of these time-reversed regions would not be born old and die young—or anything else out of the ordinary. To them, time would flow in a completely conventional fashion. It is only when comparing their universe to ours that anything seems out of the ordinary—our past is their future, and vice versa. But such a comparison is purely hypothetical, as we cannot get there and they cannot come here.
Via Arts & Letters Daily.
Quantum bounce and cosmic recall
Lisa Zyga at physorg.com:
Until very recently, asking what happened at or before the Big Bang was considered by physicists to be a religious question. General relativity theory just doesn’t go there – at T=0, it spews out zeros, infinities, and errors – and so the question didn’t make sense from a scientific view. But in the past few years, a new theory called Loop Quantum Gravity (LQG) has emerged. The theory suggests the possibility of a “quantum bounce,” where our universe stems from the collapse of a previous universe. Yet what that previous universe looked like was still beyond answering.
Now, physicists Alejandro Corichi from Universidad Nacional Autónoma de México and Parampreet Singh from the Perimeter Institute for Theoretical Physics in Ontario have developed a simplified LQG model that gives an intriguing answer: a pre-Big Bang universe might have looked a lot like ours.
From the abstract of the paper:
Loop quantum cosmology predicts that, in simple models, the big bang singularity of classical general relativity is replaced by a quantum bounce. Because of the extreme physical conditions near the bounce, a natural question is whether the universe can retain, after the bounce, its memory about the previous epoch. More precisely, does the universe retain various properties of the state after evolving unitarily through the bounce or does it suffer from some cosmic amnesia as has been recently suggested? Here we show that this issue can be answered unambiguously at least within an exactly solvable model, derived from a small simplification of loop quantum cosmology, for which there is full analytical control on the quantum theory. We show that if there exists a semiclassical state at late times on one side, peaked around a pair of canonically conjugate variables, then there are very strong bounds on the fluctuations on the other side of the bounce, implying semi-classicality. For such a model universe which grows to a size of 1 megaparsec, at late times, the change in relative fluctuations of the only non-trivial observable of the model across the bounce is less than $10^{-56}$ (becoming smaller for universes which grow larger). The universe maintains (an almost) total recall.
I have to say for a long time I have thought a very poetic answer to the "what was before the big bang" question was just that it was a continual cycle of expansion and contraction. This implies that the entire universe has a future boundary condition (see Lawrence S. Schulman), and that time will reverse and we all will live our lives backwards "again". Of course with the arrow of time running backwards, it would look like an expansion, and everything would seem normal.