![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png){kind=small}
brdgt
Well: Love, Sex and the Changing Landscape of Infidelity
By TARA PARKER-POPE, The New York Times, October 28, 2008
If you cheated on your spouse, would you admit it to a researcher?
That question is one of the biggest challenges in the scientific study of marriage, and it helps explain why different studies produce different estimates of infidelity rates in the United States.
Surveys conducted in person are likely to underestimate the real rate of adultery, because people are reluctant to admit such behavior not just to their spouses but to anyone.
In a study published last summer in The Journal of Family Psychology, for example, researchers from the University of Colorado and Texas A&M surveyed 4,884 married women, using face-to-face interviews and anonymous computer questionnaires. In the interviews, only 1 percent of women said they had been unfaithful to their husbands in the past year; on the computer questionnaire, more than 6 percent did.
At the same time, experts say that surveys appearing in sources like women’s magazines may overstate the adultery rate, because they suffer from what pollsters call selection bias: the respondents select themselves and may be more likely to report infidelity.
But a handful of new studies suggest surprising changes in the marital landscape. Infidelity appears to be on the rise, particularly among older men and young couples. Notably, women appear to be closing the adultery gap: younger women appear to be cheating on their spouses nearly as often as men.
“If you just ask whether infidelity is going up, you don’t see really impressive changes,” said David C. Atkins, research associate professor at the University of Washington Center for the Study of Health and Risk Behaviors. “But if you magnify the picture and you start looking at specific gender and age cohorts, we do start to see some pretty significant changes.”
The most consistent data on infidelity come from the General Social Survey, sponsored by the National Science Foundation and based at the University of Chicago, which has used a national representative sample to track the opinions and social behaviors of Americans since 1972. The survey data show that in any given year, about 10 percent of married people — 12 percent of men and 7 percent of women — say they have had sex outside their marriage.
But detailed analysis of the data from 1991 to 2006, to be presented next month by Dr. Atkins at the Association for Behavioral and Cognitive Therapies conference in Orlando, show some surprising shifts. University of Washington researchers have found that the lifetime rate of infidelity for men over 60 increased to 28 percent in 2006, up from 20 percent in 1991. For women over 60, the increase is more striking: to 15 percent, up from 5 percent in 1991.
The researchers also see big changes in relatively new marriages. About 20 percent of men and 15 percent of women under 35 say they have ever been unfaithful, up from about 15 and 12 percent respectively.
Theories vary about why more people appear to be cheating. Among older people, a host of newer drugs and treatments are making it easier to be sexual, and in some cases unfaithful — Viagra and other remedies for erectile dysfunction, estrogen and testosterone supplements to maintain women’s sex drive and vaginal health, even advances like better hip replacements.
“They’ve got the physical health to express their sexuality into old age,” said Helen E. Fisher, research professor of anthropology at Rutgers and the author of several books on the biological and evolutionary basis of love and sex.
In younger couples, the increasing availability of pornography on the Internet, which has been shown to affect sexual attitudes and perceptions of “normal” behavior, may be playing a role in rising infidelity.
But it is the apparent change in women’s fidelity that has sparked the most interest among relationship researchers. It is not entirely clear if the historical gap between men and women is real or if women have just been more likely to lie about it.
“Is it that men are bragging about it and women are lying to everybody including themselves?” Dr. Fisher asked. “Men want to think women don’t cheat, and women want men to think they don’t cheat, and therefore the sexes have been playing a little psychological game with each other.”
Dr. Fisher notes that infidelity is common across cultures, and that in hunting and gathering societies, there is no evidence that women are any less adulterous than men. The fidelity gap may be explained more by cultural pressures than any real difference in sex drives between men and women. Men with multiple partners typically are viewed as virile, while women are considered promiscuous. And historically, women have been isolated on farms or at home with children, giving them fewer opportunities to be unfaithful.
But today, married women are more likely to spend late hours at the office and travel on business. And even for women who stay home, cellphones, e-mail and instant messaging appear to be allowing them to form more intimate relationships, marriage therapists say. Dr. Frank Pittman, an Atlanta psychiatrist who specializes in family crisis and couples therapy, says he has noticed more women talking about affairs centered on “electronic” contact.
“I see a changing landscape in which the emphasis is less on the sex than it is on the openness and intimacy and the revelation of secrets,” said Dr. Pittman, the author of “Private Lies: Infidelity and the Betrayal of Intimacy” (Norton, 1990). “Everybody talks by cellphone and the relationship evolves because you become increasingly distant from whomever you lie to, and you become increasingly close to whomever you tell the truth to.”
While infidelity rates do appear to be rising, a vast majority of people still say adultery is wrong, and most men and women do not appear to be unfaithful. Another problem with the data is that it fails to discern when respondents cheat: in a troubled time in the marriage, or at the end of a failing relationship.
“It’s certainly plausible that women might have increased their relative rate of infidelity over time,” said Edward O. Laumann, professor of sociology at the University of Chicago. “But it isn’t going to be a huge number. The real thing to talk about is where are they in terms of their relationship and the marital bond.”
The General Social Survey data also show some encouraging trends, said John P. Robinson, professor of sociology and director of the Americans’ Use of Time project at the University of Maryland. One notable shift is that couples appear to be spending slightly more time together. And married men and women also appear to have the most active sex lives, reporting sex with their spouse 58 times a year, a little more than once a week.
“We’ve looked at that as good news,” Dr. Robinson said.
Really? Drinking Lots of Water Is Good for Your Skin
By ANAHAD O’CONNOR, The New York Times, October 28, 2008
THE FACTS
By now, the old saw about drinking eight glasses of water a day has been thoroughly debunked. But a similar adage about excess water and healthy skin persists. Where or how the claim originated is not well known, but there is no evidence that drinking anything more than recommended amounts of water is particularly beneficial to skin.
A 2007 study on the effects of water consumption did show that drinking 500 milliliters of water, about two cups, increased blood flow to the skin. A good sign, but there was no evidence that that reduced wrinkles or improved complexion. Other studies have hinted that vitamin C might prevent wrinkles, or that estrogen use in postmenopausal women might reduce dry skin and slow skin aging. But the evidence for each is limited, and estrogen therapy can have bad side effects.
Dr. Margaret E. Parsons, a spokeswoman for the American Academy of Dermatology, said excess water did not help the skin but “if dehydrated, fine wrinkles certainly seem to show up a bit more.”
“Staying appropriately hydrated is good for our general health,” she said, “and if we are eating and drinking what we should, our bodies are healthier and therefore our skin as well.”
Her advice? Always wear sunscreen, avoid cigarettes and eat well.
THE BOTTOM LINE
There is little evidence that excess water helps skin.
The Mysterious Cough, Caught on Film
By DENISE GRADY, The New York Times, October 28, 2008
In Roald Dahl’s novel “The B.F.G.,” the title character, a big friendly giant, captures dreams in glass jars. At Pennsylvania State University, a professor of engineering has captured something less whimsical but no less ephemeral — a cough — on film.
The image, published online Oct. 9 by The New England Journal of Medicine, was created by schlieren photography, which “takes an invisible phenomenon and turns it into a visible picture,” said the engineering professor, Gary Settles, who is the director of the university’s gas dynamics laboratory.
Schlieren is German for “streaks”; in this case it refers to regions of different densities in a gas or a liquid, which can be photographed as shadows using a special technique.
“In my lab we use this technique a lot,” Dr. Settles said. “Often it’s used for other things, like in supersonic wind tunnels, to show shock waves around high-speed aircraft.”
The process involves a small, bright light source, precisely placed lenses, a curved mirror, a razor blade that blocks part of the light beam and other tools that make it possible to see and photograph disturbances in the air. In the world of gas dynamics, a cough is merely “a turbulent jet of air with density changes.” Though coughs spread tuberculosis, SARS, influenza and other diseases, surprisingly little is known about them. “We don’t have a good understanding of the air flow,” Dr. Settles said.
To map a cough, he teamed up with Dr. Julian Tang, a virus expert from Singapore. A healthy student provided the cough. The expelled air, traveling at 18 miles per hour, mixed with cooler surrounding air and produced “temperature differences that bend light rays by different amounts,” Dr. Settles said.
He went on: “The next thing is, you get a couple of people in front of the mirror talking, or one coughs on another, and you see how the air flow moves, how people infect one another. Or you look at how coughing can spread airborne infection in a hospital. This is really a suggestion for how we might study all that. The techniques used in wind tunnels can be used to study human diseases.”
Other schlieren images show the churning air and shock waves that emanate from a pistol’s firing; an Airedale sniffing a small flower; and the unseen, shimmering world around a candle burning in a breeze.
The final photograph, in a full-scale mock-up of an aircraft cabin, captures in microseconds the flash of an explosion under a mannequin in an airplane seat and the propagation of shock waves into the cabin. The blast was a re-creation of a terrorist’s attempt in 1994 to bring down a Philippine Airlines flight with a nitroglycerin bomb. The plane did not crash, but the explosion did kill the passenger seated over the bomb. The simulation used a less intense explosion than the actual bombing.
“The simulation helps to understand how the energy of an onboard blast reverberates around the cabin,” Dr. Settles said, “and it is also useful to check the results of computer blast simulations.”
Scotch Tape Unleashes X-Ray Power
By KENNETH CHANG, The New York Times, October 28, 2008
In a tour de force of office supply physics, researchers at the University of California, Los Angeles, have shown that it is possible to produce X-rays by simply unrolling Scotch tape.
Next step: nuclear fusion.
“We’re going to do that,” said Seth J. Putterman, a professor of physics at U.C.L.A. “I think it will work.”
But first, X-rays.
In the current issue of the journal Nature, Dr. Putterman and his colleagues report that surprisingly fierce flows of electrons were unleashed as the tape was unpeeled and its gooey adhesive snapped free of the surface. The electrical currents, in turn, generated strong, short bursts of X-rays — each burst, about a billionth of a second long, contained about 300,000 X-ray photons.
“Some kind of microscopic lightning effect,” Dr. Putterman said.
The scientists even demonstrated that the X-rays were bright enough to take an X-ray of a finger.
That does not mean that tape dispensers on office desks are mini X-ray machines. The phenomenon has been observed only when tape is unpeeled in a vacuum. Something about air, moisture perhaps, short-circuits the X-rays.
The work is not unprecedented. In 1939, scientists showed that peeling tape emits light, an experiment anyone can conduct in a closet. But visible light photons have only about one ten-thousandth the energy of an X-ray photon.
Russian scientists reported as far back as 1953 that from tape they had detected electrons energetic enough to emit X-rays. “But as far as I can tell, no one ever believed them,” Dr. Putterman said. “It was a big surprise to discover this deep dark corner of past research.”
All of the experiments were conducted with Scotch tape, manufactured by 3M. The details of what is occurring on the molecular scale are not known, the scientists said, in part because the Scotch adhesive remains a trade secret.
Other brands of clear adhesive tapes also gave off X-rays, but with a different spectrum of energies. Duct tape did not produce any X-rays, Dr. Putterman said. Masking tape has not been tested.
The research opens up the possibility of looking for X-ray emissions from composite materials as they fatigue. Such materials, increasingly used in airplanes and automobiles, do not show the visible weaknesses that metals do before breaking.
The tape phenomenon could also lead to simple medical devices using bursts of electrons to destroy tumors. The scientists are looking to patent their ideas.
Finally, there is the possibility of nuclear fusion. If energy from the breaking adhesive could be directed away from the electrons to heavy hydrogen ions implanted in modified tape, the ions would accelerate so that when they collided, they could fuse and give off energy — the process that lights the sun.
Thoreau Is Rediscovered as a Climatologist
By CORNELIA DEAN, The New York Times, October 28, 2008
CONCORD, Mass. — Henry David Thoreau endorsed civil disobedience, opposed slavery and lived for two years in a hut in the woods here, an experience he described in “Walden.” Now he turns out to have another line in his résumé: climate researcher.
He did not realize it, of course. Thoreau died in 1862, when the industrial revolution was just beginning to pump climate-changing greenhouse gases into the atmosphere. In 1851, when he started recording when and where plants flowered in Concord, he was making notes for a book on the seasons.
Now, though, researchers at Boston University and Harvard are using those notes to discern patterns of plant abundance and decline in Concord — and by extension, New England — and to link those patterns to changing climate.
Their conclusions are clear. On average, common species are flowering seven days earlier than they did in Thoreau’s day, Richard B. Primack, a conservation biologist at Boston University, and Abraham J. Miller-Rushing, then his graduate student, reported this year in the journal Ecology. Working with Charles C. Davis, an evolutionary biologist at Harvard and two of his graduate students, they determined that 27 percent of the species documented by Thoreau have vanished from Concord and 36 percent are present in such small numbers that they probably will not survive for long. Those findings appear in the current issue of the Proceedings of the National Academy of Sciences.
“It’s targeting certain branches in the tree of life,” Dr. Davis said. “They happen to be our most charismatic species — orchids, mints, gentians, lilies, iris.”
Of the 21 species of orchids Thoreau observed in Concord, “we could only find 7,” Dr. Primack said.
From 1851 through 1858, Thoreau tracked the first flowerings of perhaps 500 species, Dr. Primack said. “He knew what he was doing, and he did it really systematically.”
Dr. Primack and Dr. Miller-Rushing did their own surveys in 2004, 2005 and 2006. They also consulted notes from Pennie Logemann, a landscape designer who tracked flowering times from 1963 to 1993 as an aid to planning Concord gardens. And they looked at contributions by members of area plant, insect and bird clubs and the work of additional participants in Concord’s long line of passionate amateur naturalists, some of whose records are preserved in the Free Public Library here.
One of them, Richard J. Eaton, is best known to botanists for his 1974 book, “A Flora of Concord.” Dr. Primack recalled that as a graduate student at Harvard, he had worked alongside Mr. Eaton in the university’s natural history collection — curators relegated the two of them to the same obscure table. “He was just this very elderly man,” Dr. Primack recalled. “Not a professor, an enthusiast. But he was a very, very good botanist. He used very good methods.”
Another contributor, Alfred Hosmer, is more obscure, but his contribution is enormous: detailed notes he made in Concord from 1888 through 1902.
“He was a storekeeper,” Dr. Primack told a small group of graduate students as he gathered them around a table in a special collections room in the Concord library one recent morning. He opened a gray cardboard box, sifted through photocopies of Thoreau’s notoriously hard-to-read notes and pulled out what looked like an ancient composition book. He turned to a page where an inventory of orchid species ended and one of irises began. The entries move across the page in tiny but precise script.
“You can imagine this as a storekeeper’s ledger,” Dr. Primack said. But Hosmer’s plant nomenclature was more accurate than Thoreau’s, he said. “Plus we can read his writing.”
According to Dr. Primack, Hosmer spent “15 years walking around Concord for several hours a day several times a week” making notes about plants. “He never wrote about why he was doing this,” Dr. Primack said, “but he had known Thoreau when he was a boy. Hosmer was one of the first people who said Thoreau was a genius and not just a nut.”
Dr. Primack said he had never heard of Hosmer until his interest in Thoreau led him to search for old journals, diaries and other records. “I started going to all these funny scientific societies we have,” he said. “I was getting up in the ‘new business’ and telling people what I was looking for. I got a lot of leads, but most were not very useful. Then Ray Angelo told me about Hosmer.”
Mr. Angelo, who stepped down recently as curator of vascular plants at the New England Botanical Club, is the author of a monograph, “Concord Area Trees and Shrubs.” The eminent biologist Ernst Mayr once called him “the most knowledgeable student of the Concord flora” and today, when Dr. Primack and the other researchers are looking for this species or that in Concord, Mr. Angelo tells them where to find it.
The most daunting challenge, though, was making sense of this kind of data.
“There were a couple of big problems,” Dr. Miller-Rushing, now at the University of Maryland, said in a telephone interview from Colorado, where he was studying mountain plants. “Thoreau had incredibly messy handwriting. That was a big difficulty.” Also, he said, “in some cases he and Hosmer called the same species by different names. We had to figure all that out.”
Their work with Dr. Davis and his students began then, after they heard the two give talks at Harvard on their efforts and convinced them additional analysis was necessary.
“We just treated each individual species as a data point,” Dr. Primack said. “That was not the way to do it.” Dr. Davis and two of his graduate students, Charles G. Willis and Brad Ruhfel, began looking at the species data from an evolutionary perspective including, for example, the relationship between species traits and abundance. “Those species that are falling out are more closely related than you would expect,” Mr. Willis said.
As Dr. Davis put it, “certain branches of the tree of life are being lopped off.”
But when Dr. Davis and his colleagues began analyzing the data, things got off to a rough start. “It’s actually a very specialized kind of analysis,” Dr. Primack said. Mr. Willis “kept explaining what the analysis was showing, and I kept saying, ‘I don’t understand.’ ”
Once he did understand, he added, it became apparent that “a couple of times they had not done the analysis correctly because they did not understand the field data.”
Now, though, they have figured out how to communicate. “Climate change, ecology and evolutionary biology have been going their own separate ways,” Mr. Ruhfel said. “We see now we have information we can share and really further the field.”
Now the professors and their graduate students are on the trail of more data. For example, there is growing evidence that as birds change their migration patterns in response to climate change, they may no longer be in sync with the insect species they feed on. Elizabeth Bacon, another of Dr. Primack’s graduate students, is combing Thoreau’s notes on birds and the records of the Nuttall Ornithological Club, a local organization, to see what they can contribute.
Dr. Miller-Rushing worked this summer in the Rockies on whether plants that begin to flower earlier have more problems with late-season frost.
Mr. Willis and Mr. Ruhfel are looking at which species are moving in to Concord to occupy niches vacated by vanished plants, and whether they come from “adjacent species pools,” as Mr. Willis puts it.
The scientists say their research demonstrates the importance of simply watching the landscape and recording what occurs in it. And it demonstrates the importance of old records and natural history collections, Dr. Davis said. But in general, he said, there is little interest in devoting money, time and space to their preservation.
“It’s hard to defend the space on major campuses,” Dr. Davis said. “Eaton could not have prepared his ‘Flora’ unless Harvard University had maintained herbarium specimens. Hosmer’s book was here in Concord for 100 years before anyone used it.”
By TARA PARKER-POPE, The New York Times, October 28, 2008
If you cheated on your spouse, would you admit it to a researcher?
That question is one of the biggest challenges in the scientific study of marriage, and it helps explain why different studies produce different estimates of infidelity rates in the United States.
Surveys conducted in person are likely to underestimate the real rate of adultery, because people are reluctant to admit such behavior not just to their spouses but to anyone.
In a study published last summer in The Journal of Family Psychology, for example, researchers from the University of Colorado and Texas A&M surveyed 4,884 married women, using face-to-face interviews and anonymous computer questionnaires. In the interviews, only 1 percent of women said they had been unfaithful to their husbands in the past year; on the computer questionnaire, more than 6 percent did.
At the same time, experts say that surveys appearing in sources like women’s magazines may overstate the adultery rate, because they suffer from what pollsters call selection bias: the respondents select themselves and may be more likely to report infidelity.
But a handful of new studies suggest surprising changes in the marital landscape. Infidelity appears to be on the rise, particularly among older men and young couples. Notably, women appear to be closing the adultery gap: younger women appear to be cheating on their spouses nearly as often as men.
“If you just ask whether infidelity is going up, you don’t see really impressive changes,” said David C. Atkins, research associate professor at the University of Washington Center for the Study of Health and Risk Behaviors. “But if you magnify the picture and you start looking at specific gender and age cohorts, we do start to see some pretty significant changes.”
The most consistent data on infidelity come from the General Social Survey, sponsored by the National Science Foundation and based at the University of Chicago, which has used a national representative sample to track the opinions and social behaviors of Americans since 1972. The survey data show that in any given year, about 10 percent of married people — 12 percent of men and 7 percent of women — say they have had sex outside their marriage.
But detailed analysis of the data from 1991 to 2006, to be presented next month by Dr. Atkins at the Association for Behavioral and Cognitive Therapies conference in Orlando, show some surprising shifts. University of Washington researchers have found that the lifetime rate of infidelity for men over 60 increased to 28 percent in 2006, up from 20 percent in 1991. For women over 60, the increase is more striking: to 15 percent, up from 5 percent in 1991.
The researchers also see big changes in relatively new marriages. About 20 percent of men and 15 percent of women under 35 say they have ever been unfaithful, up from about 15 and 12 percent respectively.
Theories vary about why more people appear to be cheating. Among older people, a host of newer drugs and treatments are making it easier to be sexual, and in some cases unfaithful — Viagra and other remedies for erectile dysfunction, estrogen and testosterone supplements to maintain women’s sex drive and vaginal health, even advances like better hip replacements.
“They’ve got the physical health to express their sexuality into old age,” said Helen E. Fisher, research professor of anthropology at Rutgers and the author of several books on the biological and evolutionary basis of love and sex.
In younger couples, the increasing availability of pornography on the Internet, which has been shown to affect sexual attitudes and perceptions of “normal” behavior, may be playing a role in rising infidelity.
But it is the apparent change in women’s fidelity that has sparked the most interest among relationship researchers. It is not entirely clear if the historical gap between men and women is real or if women have just been more likely to lie about it.
“Is it that men are bragging about it and women are lying to everybody including themselves?” Dr. Fisher asked. “Men want to think women don’t cheat, and women want men to think they don’t cheat, and therefore the sexes have been playing a little psychological game with each other.”
Dr. Fisher notes that infidelity is common across cultures, and that in hunting and gathering societies, there is no evidence that women are any less adulterous than men. The fidelity gap may be explained more by cultural pressures than any real difference in sex drives between men and women. Men with multiple partners typically are viewed as virile, while women are considered promiscuous. And historically, women have been isolated on farms or at home with children, giving them fewer opportunities to be unfaithful.
But today, married women are more likely to spend late hours at the office and travel on business. And even for women who stay home, cellphones, e-mail and instant messaging appear to be allowing them to form more intimate relationships, marriage therapists say. Dr. Frank Pittman, an Atlanta psychiatrist who specializes in family crisis and couples therapy, says he has noticed more women talking about affairs centered on “electronic” contact.
“I see a changing landscape in which the emphasis is less on the sex than it is on the openness and intimacy and the revelation of secrets,” said Dr. Pittman, the author of “Private Lies: Infidelity and the Betrayal of Intimacy” (Norton, 1990). “Everybody talks by cellphone and the relationship evolves because you become increasingly distant from whomever you lie to, and you become increasingly close to whomever you tell the truth to.”
While infidelity rates do appear to be rising, a vast majority of people still say adultery is wrong, and most men and women do not appear to be unfaithful. Another problem with the data is that it fails to discern when respondents cheat: in a troubled time in the marriage, or at the end of a failing relationship.
“It’s certainly plausible that women might have increased their relative rate of infidelity over time,” said Edward O. Laumann, professor of sociology at the University of Chicago. “But it isn’t going to be a huge number. The real thing to talk about is where are they in terms of their relationship and the marital bond.”
The General Social Survey data also show some encouraging trends, said John P. Robinson, professor of sociology and director of the Americans’ Use of Time project at the University of Maryland. One notable shift is that couples appear to be spending slightly more time together. And married men and women also appear to have the most active sex lives, reporting sex with their spouse 58 times a year, a little more than once a week.
“We’ve looked at that as good news,” Dr. Robinson said.
Really? Drinking Lots of Water Is Good for Your Skin
By ANAHAD O’CONNOR, The New York Times, October 28, 2008
THE FACTS
By now, the old saw about drinking eight glasses of water a day has been thoroughly debunked. But a similar adage about excess water and healthy skin persists. Where or how the claim originated is not well known, but there is no evidence that drinking anything more than recommended amounts of water is particularly beneficial to skin.
A 2007 study on the effects of water consumption did show that drinking 500 milliliters of water, about two cups, increased blood flow to the skin. A good sign, but there was no evidence that that reduced wrinkles or improved complexion. Other studies have hinted that vitamin C might prevent wrinkles, or that estrogen use in postmenopausal women might reduce dry skin and slow skin aging. But the evidence for each is limited, and estrogen therapy can have bad side effects.
Dr. Margaret E. Parsons, a spokeswoman for the American Academy of Dermatology, said excess water did not help the skin but “if dehydrated, fine wrinkles certainly seem to show up a bit more.”
“Staying appropriately hydrated is good for our general health,” she said, “and if we are eating and drinking what we should, our bodies are healthier and therefore our skin as well.”
Her advice? Always wear sunscreen, avoid cigarettes and eat well.
THE BOTTOM LINE
There is little evidence that excess water helps skin.
The Mysterious Cough, Caught on Film
By DENISE GRADY, The New York Times, October 28, 2008
In Roald Dahl’s novel “The B.F.G.,” the title character, a big friendly giant, captures dreams in glass jars. At Pennsylvania State University, a professor of engineering has captured something less whimsical but no less ephemeral — a cough — on film.
The image, published online Oct. 9 by The New England Journal of Medicine, was created by schlieren photography, which “takes an invisible phenomenon and turns it into a visible picture,” said the engineering professor, Gary Settles, who is the director of the university’s gas dynamics laboratory.
Schlieren is German for “streaks”; in this case it refers to regions of different densities in a gas or a liquid, which can be photographed as shadows using a special technique.
“In my lab we use this technique a lot,” Dr. Settles said. “Often it’s used for other things, like in supersonic wind tunnels, to show shock waves around high-speed aircraft.”
The process involves a small, bright light source, precisely placed lenses, a curved mirror, a razor blade that blocks part of the light beam and other tools that make it possible to see and photograph disturbances in the air. In the world of gas dynamics, a cough is merely “a turbulent jet of air with density changes.” Though coughs spread tuberculosis, SARS, influenza and other diseases, surprisingly little is known about them. “We don’t have a good understanding of the air flow,” Dr. Settles said.
To map a cough, he teamed up with Dr. Julian Tang, a virus expert from Singapore. A healthy student provided the cough. The expelled air, traveling at 18 miles per hour, mixed with cooler surrounding air and produced “temperature differences that bend light rays by different amounts,” Dr. Settles said.
He went on: “The next thing is, you get a couple of people in front of the mirror talking, or one coughs on another, and you see how the air flow moves, how people infect one another. Or you look at how coughing can spread airborne infection in a hospital. This is really a suggestion for how we might study all that. The techniques used in wind tunnels can be used to study human diseases.”
Other schlieren images show the churning air and shock waves that emanate from a pistol’s firing; an Airedale sniffing a small flower; and the unseen, shimmering world around a candle burning in a breeze.
The final photograph, in a full-scale mock-up of an aircraft cabin, captures in microseconds the flash of an explosion under a mannequin in an airplane seat and the propagation of shock waves into the cabin. The blast was a re-creation of a terrorist’s attempt in 1994 to bring down a Philippine Airlines flight with a nitroglycerin bomb. The plane did not crash, but the explosion did kill the passenger seated over the bomb. The simulation used a less intense explosion than the actual bombing.
“The simulation helps to understand how the energy of an onboard blast reverberates around the cabin,” Dr. Settles said, “and it is also useful to check the results of computer blast simulations.”
Scotch Tape Unleashes X-Ray Power
By KENNETH CHANG, The New York Times, October 28, 2008
In a tour de force of office supply physics, researchers at the University of California, Los Angeles, have shown that it is possible to produce X-rays by simply unrolling Scotch tape.
Next step: nuclear fusion.
“We’re going to do that,” said Seth J. Putterman, a professor of physics at U.C.L.A. “I think it will work.”
But first, X-rays.
In the current issue of the journal Nature, Dr. Putterman and his colleagues report that surprisingly fierce flows of electrons were unleashed as the tape was unpeeled and its gooey adhesive snapped free of the surface. The electrical currents, in turn, generated strong, short bursts of X-rays — each burst, about a billionth of a second long, contained about 300,000 X-ray photons.
“Some kind of microscopic lightning effect,” Dr. Putterman said.
The scientists even demonstrated that the X-rays were bright enough to take an X-ray of a finger.
That does not mean that tape dispensers on office desks are mini X-ray machines. The phenomenon has been observed only when tape is unpeeled in a vacuum. Something about air, moisture perhaps, short-circuits the X-rays.
The work is not unprecedented. In 1939, scientists showed that peeling tape emits light, an experiment anyone can conduct in a closet. But visible light photons have only about one ten-thousandth the energy of an X-ray photon.
Russian scientists reported as far back as 1953 that from tape they had detected electrons energetic enough to emit X-rays. “But as far as I can tell, no one ever believed them,” Dr. Putterman said. “It was a big surprise to discover this deep dark corner of past research.”
All of the experiments were conducted with Scotch tape, manufactured by 3M. The details of what is occurring on the molecular scale are not known, the scientists said, in part because the Scotch adhesive remains a trade secret.
Other brands of clear adhesive tapes also gave off X-rays, but with a different spectrum of energies. Duct tape did not produce any X-rays, Dr. Putterman said. Masking tape has not been tested.
The research opens up the possibility of looking for X-ray emissions from composite materials as they fatigue. Such materials, increasingly used in airplanes and automobiles, do not show the visible weaknesses that metals do before breaking.
The tape phenomenon could also lead to simple medical devices using bursts of electrons to destroy tumors. The scientists are looking to patent their ideas.
Finally, there is the possibility of nuclear fusion. If energy from the breaking adhesive could be directed away from the electrons to heavy hydrogen ions implanted in modified tape, the ions would accelerate so that when they collided, they could fuse and give off energy — the process that lights the sun.
Thoreau Is Rediscovered as a Climatologist
By CORNELIA DEAN, The New York Times, October 28, 2008
CONCORD, Mass. — Henry David Thoreau endorsed civil disobedience, opposed slavery and lived for two years in a hut in the woods here, an experience he described in “Walden.” Now he turns out to have another line in his résumé: climate researcher.
He did not realize it, of course. Thoreau died in 1862, when the industrial revolution was just beginning to pump climate-changing greenhouse gases into the atmosphere. In 1851, when he started recording when and where plants flowered in Concord, he was making notes for a book on the seasons.
Now, though, researchers at Boston University and Harvard are using those notes to discern patterns of plant abundance and decline in Concord — and by extension, New England — and to link those patterns to changing climate.
Their conclusions are clear. On average, common species are flowering seven days earlier than they did in Thoreau’s day, Richard B. Primack, a conservation biologist at Boston University, and Abraham J. Miller-Rushing, then his graduate student, reported this year in the journal Ecology. Working with Charles C. Davis, an evolutionary biologist at Harvard and two of his graduate students, they determined that 27 percent of the species documented by Thoreau have vanished from Concord and 36 percent are present in such small numbers that they probably will not survive for long. Those findings appear in the current issue of the Proceedings of the National Academy of Sciences.
“It’s targeting certain branches in the tree of life,” Dr. Davis said. “They happen to be our most charismatic species — orchids, mints, gentians, lilies, iris.”
Of the 21 species of orchids Thoreau observed in Concord, “we could only find 7,” Dr. Primack said.
From 1851 through 1858, Thoreau tracked the first flowerings of perhaps 500 species, Dr. Primack said. “He knew what he was doing, and he did it really systematically.”
Dr. Primack and Dr. Miller-Rushing did their own surveys in 2004, 2005 and 2006. They also consulted notes from Pennie Logemann, a landscape designer who tracked flowering times from 1963 to 1993 as an aid to planning Concord gardens. And they looked at contributions by members of area plant, insect and bird clubs and the work of additional participants in Concord’s long line of passionate amateur naturalists, some of whose records are preserved in the Free Public Library here.
One of them, Richard J. Eaton, is best known to botanists for his 1974 book, “A Flora of Concord.” Dr. Primack recalled that as a graduate student at Harvard, he had worked alongside Mr. Eaton in the university’s natural history collection — curators relegated the two of them to the same obscure table. “He was just this very elderly man,” Dr. Primack recalled. “Not a professor, an enthusiast. But he was a very, very good botanist. He used very good methods.”
Another contributor, Alfred Hosmer, is more obscure, but his contribution is enormous: detailed notes he made in Concord from 1888 through 1902.
“He was a storekeeper,” Dr. Primack told a small group of graduate students as he gathered them around a table in a special collections room in the Concord library one recent morning. He opened a gray cardboard box, sifted through photocopies of Thoreau’s notoriously hard-to-read notes and pulled out what looked like an ancient composition book. He turned to a page where an inventory of orchid species ended and one of irises began. The entries move across the page in tiny but precise script.
“You can imagine this as a storekeeper’s ledger,” Dr. Primack said. But Hosmer’s plant nomenclature was more accurate than Thoreau’s, he said. “Plus we can read his writing.”
According to Dr. Primack, Hosmer spent “15 years walking around Concord for several hours a day several times a week” making notes about plants. “He never wrote about why he was doing this,” Dr. Primack said, “but he had known Thoreau when he was a boy. Hosmer was one of the first people who said Thoreau was a genius and not just a nut.”
Dr. Primack said he had never heard of Hosmer until his interest in Thoreau led him to search for old journals, diaries and other records. “I started going to all these funny scientific societies we have,” he said. “I was getting up in the ‘new business’ and telling people what I was looking for. I got a lot of leads, but most were not very useful. Then Ray Angelo told me about Hosmer.”
Mr. Angelo, who stepped down recently as curator of vascular plants at the New England Botanical Club, is the author of a monograph, “Concord Area Trees and Shrubs.” The eminent biologist Ernst Mayr once called him “the most knowledgeable student of the Concord flora” and today, when Dr. Primack and the other researchers are looking for this species or that in Concord, Mr. Angelo tells them where to find it.
The most daunting challenge, though, was making sense of this kind of data.
“There were a couple of big problems,” Dr. Miller-Rushing, now at the University of Maryland, said in a telephone interview from Colorado, where he was studying mountain plants. “Thoreau had incredibly messy handwriting. That was a big difficulty.” Also, he said, “in some cases he and Hosmer called the same species by different names. We had to figure all that out.”
Their work with Dr. Davis and his students began then, after they heard the two give talks at Harvard on their efforts and convinced them additional analysis was necessary.
“We just treated each individual species as a data point,” Dr. Primack said. “That was not the way to do it.” Dr. Davis and two of his graduate students, Charles G. Willis and Brad Ruhfel, began looking at the species data from an evolutionary perspective including, for example, the relationship between species traits and abundance. “Those species that are falling out are more closely related than you would expect,” Mr. Willis said.
As Dr. Davis put it, “certain branches of the tree of life are being lopped off.”
But when Dr. Davis and his colleagues began analyzing the data, things got off to a rough start. “It’s actually a very specialized kind of analysis,” Dr. Primack said. Mr. Willis “kept explaining what the analysis was showing, and I kept saying, ‘I don’t understand.’ ”
Once he did understand, he added, it became apparent that “a couple of times they had not done the analysis correctly because they did not understand the field data.”
Now, though, they have figured out how to communicate. “Climate change, ecology and evolutionary biology have been going their own separate ways,” Mr. Ruhfel said. “We see now we have information we can share and really further the field.”
Now the professors and their graduate students are on the trail of more data. For example, there is growing evidence that as birds change their migration patterns in response to climate change, they may no longer be in sync with the insect species they feed on. Elizabeth Bacon, another of Dr. Primack’s graduate students, is combing Thoreau’s notes on birds and the records of the Nuttall Ornithological Club, a local organization, to see what they can contribute.
Dr. Miller-Rushing worked this summer in the Rockies on whether plants that begin to flower earlier have more problems with late-season frost.
Mr. Willis and Mr. Ruhfel are looking at which species are moving in to Concord to occupy niches vacated by vanished plants, and whether they come from “adjacent species pools,” as Mr. Willis puts it.
The scientists say their research demonstrates the importance of simply watching the landscape and recording what occurs in it. And it demonstrates the importance of old records and natural history collections, Dr. Davis said. But in general, he said, there is little interest in devoting money, time and space to their preservation.
“It’s hard to defend the space on major campuses,” Dr. Davis said. “Eaton could not have prepared his ‘Flora’ unless Harvard University had maintained herbarium specimens. Hosmer’s book was here in Concord for 100 years before anyone used it.”
