Tag Archives: science

Acoustic levitation: straight-up amazing

This was created by Yoichi Ochiai, Takayuki Hoshi and Jun Rekimoto, who say:

The essence of levitation technology is the countervailing of gravity. It is known that an ultrasound standing wave is capable of suspending small particles at its sound pressure nodes. The acoustic axis of the ultrasound beam in conventional studies was parallel to the gravitational force, and the levitated objects were manipulated along the fixed axis (i.e. one-dimensionally) by controlling the phases or frequencies of bolted Langevin-type transducers. In the present study, we considered extended acoustic manipulation whereby millimetre-sized particles were levitated and moved three-dimensionally by localised ultrasonic standing waves, which were generated by ultrasonic phased arrays. Our manipulation system has two original features. One is the direction of the ultrasound beam, which is arbitrary because the force acting toward its centre is also utilised. The other is the manipulation principle by which a localised standing wave is generated at an arbitrary position and moved three-dimensionally by opposed and ultrasonic phased arrays. We experimentally confirmed that expanded-polystyrene particles of 0.6 mm and 2 mm in diameter could be manipulated by our proposed method.

Got that?

Get their PDF here.

Richard Feynmann – the pleasure of finding things out

Photomicography – it’s a small world after all. Best viewed large.

Nikon Small World 2013Colonial plankton organism, Chaetoceros debilis (marine diatom), magnified 250x by Wim van Egmond, of the Micropolitan Museum, Berkel en Rodenrijs, Zuid Holland, Netherlands.

The Atlantic always finds the best pictures
. Here it shows the winners of the 2013 Nikon Small World Photomicrography Competition. Started back in 1974, the contest invites photographers and scientists to submit images of all things visible under a microscope.

First place this year went to a 250x view of a marine diatom by Wim van Egmond (above), showing the complexity and stunning detail of its fragile helical chain. Other entries included close-up views of ladybug feet, mollusc radula, dinosaur bones, nerve structures in embryos, and much more. Enjoy a journey into mini things by clicking here. Needless to say, best viewed large!

s04_20022382A 4x image of a worker ant, (Aphaenogaster senilis) by Dimitri Seeboruth, from Paris, France.

Your grammar influences the way you spend, eat and live

Well, this is fascinating. Especially since I’ve been looking at a lot of shopper marketing recently, as well as talking to insurance people about how AJP region differs from, say, EMEA. Companies get astonishingly detailed info about people’s habits, but having read the article below and seen the brilliant video that summarises Keith Chen’s hypothesis, I wonder if they already look at what languages we speak to work out likelihood to X or Y.

Article below by Derek Thompson, originally from Atlantic. The original article also has a chart you might find interesting, but the whole thing is summed up nicely in this video. Though I’ve got to say, the last bit about death and so on seems like latched-on stats. The link there is wooly, which is a shame, as I loved the rest of it. Anyway, make up your own mind:

Can Your Language Influence Your Spending, Eating, and Smoking Habits?

An absurd-sounding claim leads to a surprising finding

Yes, I know. That headline. It looks like the most egregious form of causal inference. Americans don’t save money because of … our grammar? How utterly absurd. But bear with me.

In the 1930s, linguists proposed that the way we read, write, and talk helped to determine the way we see the world. Speakers of languages that had the same word for orange and yellow had a harder time actually distinguishing the colors. Speakers of the Kook Thaayorre language, which has no words for left and right, must orient themselves by north, south, east, and west at all time, which enhances their awareness of geographical and astronomical markers.

Last year, economist Keith Chen released a working paper (now published) suggesting speakers of languages without strong future tenses tended to be more responsible about planning for the future. Quick example. In English, we say “I will go to the play tomorrow.” That’s strong future tense. In Mandarin or Finnish, which have weaker future tenses, it might be more appropriate to say, “I go to the play tomorrow.”

Chen wondered whether languages with weak future tenses would be more thoughtful about the future because they consider it, grammatically, equivalent to the present. He mapped stronger and weak future-tense languages across Europe and correlated the data with future-oriented behaviors like saving, smoking, and using condoms.

Remarkably, he discovered that speakers with weak future tenses (e.g. German, Finnish and Estonian) were 30 percent more likely to save money, 24 percent more likely to avoid smoking, 29 percent more likely to exercise regularly, and 13 percent less likely to be obese, than speakers of languages with strong future tenses, like English.

If your B.S. antennae are standing straight up (as mine were), you might be more interested in this next part. Chen next compared speakers born and raised within the same countries, as well, controlling for factors like age and number of children. He found the same results: Speakers with weak future tenses demonstrated dramatically, and statistically significantly, more responsible future-oriented behaviors — even within countries like Switzerland, which are a motley blend of strong-future languages (like French) and weak-future languages (like German).

The correlation was savaged by some economists and linguists as facile or worse. But others re-ran the data and found, to their astonishment, that Chen seemed to be right. His paper was published (along with thanks to some of his fiercest critics) in the American Economic Review this year.

“One important issue in interpreting these results is the possibility that language is not causing but rather reflecting deeper differences that drive savings behavior,” Chen concluded. Languages map to large groups of people, but so does religion, culture, family values, and a common history. Are Germans frugal because their language protects them from hyperbolic discounting, or is it just that, well, they’re Germans?

That question doesn’t have a satisfying answer, but this paper, as wild as it seems, isn’t a radical departure from the literature. “Overall, my findings are largely consistent with the hypothesis that languages with obligatory future-time reference lead their speakers to engage in less future-oriented behavior,” Chen wrote.

What does it mean? I have no idea, and Chen himself has responded to the criticism of his work with an honorable blend of erudition and shrugging disbelief. But I suppose that if you suffer from issues like crippling procrastination, as I do, it couldn’t hurt to learn Estonian — or, perhaps more simply, to write inspirational notes to yourself exclusively in the present tense. The future might be a different country, but it doesn’t have to feel that way.

Common misconceptions

There’s an excellent list of common misconceptions on Wikipedia, which Kottke has helpfully pointed out. Among them, some of my favourites:

In ancient Rome, the architectural feature called a vomitorium was the entranceway through which crowds entered and exited a stadium, not a special room used for purging food during meals.[1] Vomiting was not a regular part of Roman dining customs.[2]

It is true that mean life expectancy in the Middle Ages and earlier was low; however, many take this to mean that people usually died around the age of 30.[5] In fact, the low life expectancy is an average very strongly influenced by high infant mortality, and the life expectancy of people who lived to adulthood was much higher. A 21-year-old man in medieval England, for example, could by one estimate expect to live to the age of 64.[6]

George Washington did not have wooden teeth. His dentures were made of gold, hippopotamus ivory, lead, and human and animal teeth (including horse and donkey teeth).[34]

Some people believe that food items cooked with wine or liquor will be totally non-alcoholic, because alcohol’s low boiling point causes it to evaporate quickly when heated. However, a study found that some of the alcohol remains: 25% after 1 hour of baking or simmering, and 10% after 2 hours.[88][89]

Meteorites are not necessarily hot when they reach the Earth. In fact, many meteorites are found with frost on them. As they enter the atmosphere, having been warmed only by the sun, meteors have a temperature below freezing. The intense heat produced during passage through the upper atmosphere at very high speed then melts a meteor’s outside layer, but molten material is blown off and the interior does not have time to warm appreciably. Most meteorites fall through the relatively cool lower atmosphere for as long as several minutes at subsonic velocity before reaching the ground, giving plenty of time for their exterior to cool off again.[170]

When a spacecraft reenters the atmosphere, the heat of reentry is not (primarily) caused by friction, but by adiabatic compression of air in front of the spacecraft.[171][172]

There is a legend that Marco Polo imported pasta from China[20] which originated with the Macaroni Journal, published by an association of food industries with the goal of promoting the use of pasta in the United States.[21] Marco Polo describes a food similar to “lagana” in his Travels, but he uses a term with which he was already familiar. Durum wheat, and thus pasta as it is known today, was introduced by Arabs from Libya, during their conquest of Sicilyin the late 7th century, according to the newsletter of the National Macaroni Manufacturers Association,[22] thus predating Marco Polo’s travels to China by about six centuries.

It is rarely necessary to wait 24 hours before filing a missing person’s report; in instances where there is evidence of violence or of an unusual absence, law enforcement agencies in the United States often stress the importance of beginning an investigation promptly.[77][78][79] The UK government Web site says explicitly in large type “You don’t have to wait 24 hours before contacting the police”[80].

Searing meat does not “seal in” moisture, and in fact may actually cause meat to lose moisture. Generally, the value in searing meat is that it creates a brown crust with a rich flavor via the Maillard reaction.[86][87]

All different tastes can be detected on all parts of the tongue by taste buds,[261] with slightly increased sensitivities in different locations depending on the person, contrary to the popular belief that specific tastes only correspond to specific mapped sites on the tongue.[262] The original tongue map was based on a mistranslation of a 1901 German thesis[263] by Edwin Boring. In addition, there are not 4 but 5 primary tastes. In addition to bittersoursalty, and sweet, humans have taste receptors for umami, which is a savory or meaty taste.[264][265][266]

Humans have more than the commonly cited five senses. Although definitions vary, the actual number ranges from 9 to more than 20. In addition to sightsmelltastetouch, and hearing, which were the senses identified by Aristotle, humans can sense balance and acceleration (equilibrioception), pain (nociception), body and limb position (proprioception or kinesthetic sense), and relative temperature (thermoception).[267] Other senses sometimes identified are the sense of time, itching, pressure, hunger, thirst, fullness of the stomach, need to urinate, need to defecate, and blood carbon dioxide levels.[268][269]

Toilet waste is never intentionally jettisoned from an aircraft. All waste is collected in tanks which are emptied on the ground by toilet waste vehicles.[431] Blue ice is caused by accidental leakage from the waste tank. Passenger trains, on the other hand, have historicallyflushed onto the tracks; however, modern trains usually have retention tanks on board.

(An excellent list, no? Full list here)

The Long Swath

On April 12, 2013, the Landsat Data Continuity Mission (LDCM) reached its final orbit, 705 kilometers (438 miles) above Earth. One week later, the satellite’s natural-color imager scanned a swath of land 185-kilometers wide and 9,000 kilometers long (120 by 6,000 miles)—an unusual, unbroken distance considering 70 percent of Earth is covered with water. That flight path—depicted on the globe below—afforded us the chance to assemble 56 still images into a seamless, flyover view of what LDCM saw on April 19, 2013. Stretching from northern Russia to South Africa, the full mosaic from the Operational Land Imager can be viewed in this video. Read and view more at http://earthobservatory.nasa.gov/Feat…

You’ll probably want to stick it on full screen. Make sure you’ve got some suitable music to hand.

This excellent YouTube comment by “nhstorrs” puts it in perspective: 

No way. This is amazing! Landsat flew right over the spine of the birthplace of the human species, and at the same time the birthplace of agriculture. This is where we came from, and the environment which might be said to have had the biggest impact on what made us. . . us. There could almost be no other landscape so interesting to see in one large glimpse as this one.

Three pounds of gut bacteria, microbes and a roller derby


A roller derby tournament seems like a brutal research environment: women crash around a rink in short skirts and skates, slamming their shoulders into members of the opposing team so that their own team’s “jammer” can lap them and score. But it’s perfect for researchers investigating how, through skin-to-skin contact, we might colonize other people with the microorganisms that colonize us.

When curious researchers armed with cotton swabs and strong stomachs sequence DNA from microorganisms gathered from our armpits, belly buttons, and various other locales, both inside and outside us, they find miniature versions of ecosystems like those in rain forests and meadows, composed of trillions of microbes. In aggregate, this invisible mass of organisms is our “microbiome,” and it makes up as much as three pounds of our body weight.

Although the bacteria that make up most of our microbiome (which also includes archaea and fungi) have likely evolved with us since the beginning of humanity, it is only since the advent of cheap, fast DNA sequencing that we’ve been able to study them in depth and begun to wonder what, exactly, they are doing here. There is growing evidence that our microbiomes can protect us from certain kinds of disease, or, if the balance between certain strains is disturbed, contribute to them.

The scientists at the roller derby tournament were investigating whether these microbiome bacteria spread from person to person when people touch—in this case, during a contact sport. To begin, they swabbed the upper arms of skaters on teams from three different cities before the competition started. The researchers found that each team had its own unique set of bacterial species thriving on players’ skin. The differences between them were so great that it was possible to tell just from a glance at a player’s skin bacteria which team she was from, recalls James Meadow, a microbial ecologist at the University of Oregon who is an author of the paper. Then the researchers took another set of samples after the teams had played each other.

They found that the complements of skin bacteria grew more similar, blurring the distinctions between the teams. The players were colonizing each other, it seems.

At first glance, it’s not such a surprising finding: after all, bacteria that make us sick are known to spread from person to person. But the study marks the first time that microbiome bacteria, not thought to be infectious, have been observed making the leap, and the implications reach beyond whether we swap benign bugs when standing close to strangers on the subway.

Even though the study focusses on the skin microbiome, it may have implications for other important microbial communities, like the ones in our guts. Gut bacteria, it turns out, are on everything. They are happiest when buried deep in our intestines, but they seem to leak out and have been found on our skin, in our chairs, in our beds—all over the place. “We think of clothes and things as being this really strong barrier, but all human microbiome studies to date have found that there’s a lot of overlap between these things, that these barriers that we think are nice and clean in our heads just don’t exist,” Meadow says. These bacteria don’t live for very long on skin and other surfaces—a matter of minutes—but they are constantly washing up there. Meadow says it would be odd if these bacteria from other people weren’t somehow making their way into our mouths. From there, they might head down to our guts.

Although it’s not clear whether other people’s gut bacteria can make it intact through the gauntlet of the alimentary tract, and whether they can establish themselves in our guts, it would help explain certain things. After a press conference two years ago, I had a long conversation with Balfour Sartor, a gastroenterologist at the University of North Carolina at Chapel Hill who specializes in inflammatory bowel diseases, like Crohn’s. These autoimmune conditions are thought to be caused in part by an imbalance of bacteria in the gut—too much of one kind, too little of another—and the genetic factors that abet this lopsided growth. Sartor told me that there was a growing stack of evidence, some published, some not, that people who had lived with inflammatory bowel disease sufferers for long periods of time had higher rates of it themselves than people in the general population. Since genetics aren’t contagious—at least not within a generation—this led him to wonder whether it was possible that the healthy roommates or spouses were being colonized, over time, by the malevolent bacteria.

While neither Sartor nor Meadow were aware of each other’s observations when I contacted them, according to Meadow, it would be only too easy for the spread of bacteria, at least, to take place. “People who live together, who are roommates, or spouses, have a more similar microbiome to their own housemates than they do to other people, say, in the same town,” he says. Sartor, for his part, notes a “concerning” 2007 study in which deliberately transmitting the gut bacteria of mice genetically predisposed to develop intestinal inflammation to healthy mice caused the healthy mice, in turn, to develop the condition.

These studies, taken together, raise the question of whether there is an infectious component in disease previously thought to be unspreadable, but it bears repeating that it is not clear whether bacteria added to our microbiomes from the environment establish themselves on or in our bodies for any length of time—and, if they do, whether they have any appreciable effect on our well-being. “When you do share microbes, we have no idea how important that is,” Meadow says. “We don’t know if they matter for your health at all.”

By Veronique Greenwood, from The New Yorker