SPRING….like you’ve never seen it before !

SPRING….like you’ve never seen it before !

Keukenhof – know as the Garden of Europe – is the one of the best places to view the abundance of spring flowers in the South Holland region of the Netherlands

Amsterdam's flower market – the Bloemenmarkt – reflects the country's passion for cut flowers and plants

Around seven million bulbs are planted each year in the park at Keukenhof, in an area of 32 hectares

The Bloemenmarkt - set on the capital's Singel canal and said to be the world's only floating flower market - has a score of stalls where you can buy all sorts of plants, flowers, bulbs and seeds

The mild climate of Holland , with its wet springs makes it an ideal place for bulb cultivation

Tulips originated in the east and were brought to Holland from the Ottoman Empire in the mid 1500s

In springtime, the lowland area by the North Sea is carpeted with fields of gladioli, hyacinths, lilies, daffodils, crocuses... and, of course, tulips

Keukenhof - literally 'kitchen garden' - is part of the hunting grounds of the ancient Teylingen estate

This year, the theme for the Keukenhof exhibition is Germany: Land of Poets and Philosophers

The patchwork quilt of colours in the Keukenhof park, just outside Lisse in South Holland , is a veritable feast for the eyes

The bulbs of Keukenhof are re-planted each year according to the current trends and in collaboration with a number of gardening magazines

Spring in Keukenhof is one of the main tourist attractions of the Netherlands

Blueberry's Effects on Cholesterol Examined in Lab Animal Study

An ARS laboratory animal study reports that eating blueberries lowered cholesterol levels in hamsters on a high-fat diet. (Credit: Photo by Stephen Ausmus)

Blueberry's Effects on Cholesterol Examined in Lab Animal Study

ScienceDaily  — Laboratory hamsters that were fed rations spiked with blueberry peels and other blueberry-juice-processing leftovers had better cholesterol health than hamsters whose rations weren't enhanced with blueberries. That's according to a study led by U.S. Department of Agriculture (USDA) chemist Wallace H. Yokoyama.

• 
  

Yokoyama pointed out that further research is needed to confirm whether the effects observed in hamsters hold true for humans. He works at the Western Regional Research Center operated in Albany Calif., by the Agricultural Research Service (ARS), the principal scientific research agency of USDA.

In the investigation, hamsters were fed high-fat rations. For some animals, those rations were supplemented with one of three different kinds of juice byproducts: blueberry skins-that is, peels leftover when berries are pressed to make juice; fiber extracted from the peels; or natural compounds known as polyphenols, also extracted from the peels. Blueberry polyphenols give the fruit its purple, blue, and red coloration.

In an article published in the Journal of Agricultural and Food Chemistry in 2010, Yokoyama and his coinvestigators reported that all the hamsters that were fed blueberry-enhanced rations had from 22 to 27 percent lower total plasma cholesterol than hamsters fed rations that didn't contain blueberry juice byproducts.

Levels of VLDL (very low density lipoprotein-a form of "bad" cholesterol) were about 44 percent lower in the blueberry-fed hamsters.

Yokoyama and his coinvestigators used a procedure known as real-time reverse transcription polymerase chain reaction, or RT-PCR, to learn about the genes responsible for these effects. This approach allowed the scientists to pinpoint differences in the level of activity of certain liver genes.

In hamsters-and in humans-the liver both makes cholesterol and helps get rid of excessive levels of it. Results suggest that activity of some liver genes that either produce or use cholesterol resulted in the lower blood cholesterol levels.

The study is apparently the first published account of cholesterol-lowering effects in laboratory hamsters fed blueberry peels or fiber or polyphenols extracted from those peels.

Of course, some pieces of the cholesterol puzzle are not yet in place. For example, the researchers don't know which berry compound or compounds activated the liver genes, or which parts of the berry have the highest levels of these compounds.

Yokoyama collaborated in the study with former Albany postdoctoral research associate Hyunsook Kim and ARS research chemist Agnes M. Rimando, who is based at Oxford, Miss.

More details about this study are available in the May/June 2011 issue of Agricultural Research magazine.http://www.ars.usda.gov/is/AR/archive/may11/fruit0511.htm

How the Brain Processes Faces: Neural System Responsible for Face Recognition Discovered

Science Daily — Each time you see a person that you know, your brain rapidly and seemingly effortlessly recognizes that person by his or her face.

---

Until now, scientists believed that only a couple of brain areas mediate facial recognition. However, Carnegie Mellon University's Marlene Behrmann, David Plaut and Adrian Nestor have discovered that an entire network of cortical areas work together to identify faces. Published in the current issue of theProceedings of the National Academy of Sciences (PNAS), their findings will change the future of neural visual perception research and allow scientists to use this discovery to develop targeted remedies for disorders such as face blindness.

"This research will change the types of questions asked going forward because we are not just looking at one area of the brain," said Nestor, a postdoctoral research fellow within CMU's Department of Psychology and lead author of the study. "Now, scientists will have to account for the system as a whole or else our ability to understand face individuation will be limited."

Behrmann, professor of psychology and an expert in using brain imaging to study prosopagnosia, or face blindness, agreed.

"Faces are among the most compelling visual stimulation that we encounter, and recognizing faces taxes our visual perception system to the hilt. Carnegie Mellon has a longstanding history for embracing a full-system account of the brain. We have the computational tools and technology to push further into looking past one single brain region. And, that is what we did here to discover that there are multiple cortical areas working together to recognize faces," she said.

For the study, participants were shown images of faces while in a magnetic resonance imaging (MRI) scanner. Their task was to recognize different facial identities with varying facial expressions. Using dynamic multivariate mapping, the research team examined the functional MRI (fMRI) data and found a network of fusiform and anterior temporal regions that respond with distinct patterns to different identities. Furthermore, they found that the information is evenly distributed among the anterior regions and that the right fusiform region plays a central role within the network.

"Not only do we have a more clearly defined architectural model of the brain, but we were able to determine the involvement of multiple brain areas in face recognition as well as in other types of processes, such as visual word recognition," Behrmann said.

This study was funded by the National Science Foundation, and Behrmann received additional support from the Weston Visiting Professorship at the Weizmann Institute of Science.

Link Between Environment and Genetics in Triggering Multiple Sclerosis: Discovery Points to Personalized Treatments

ScienceDaily  — Environmental and inherited risk factors associated with multiple sclerosis -- previously poorly understood and not known to be connected -- converge to alter a critical cellular function linked to the chronic neurologic disease, researchers with the UC Irvine Multiple Sclerosis Research Center have discovered.

---

The findings, which appear in the online, open-access journal Nature Communications, suggest that a unifying mechanism may be responsible for multiple sclerosis and point to therapies personalized according to genetic factors.

"MS results from complex interactions between an individual's genetics and his or her environment," said study leader Dr. Michael Demetriou, a UCI neurologist and associate director of the Multiple Sclerosis Research Center. "Defining how these come together to induce the disease is critical for developing a cure. We've taken a giant first step toward understanding this."

Using blood samples from about 13,000 people, Demetriou and colleagues identified the way environmental factors -- including metabolism and vitamin D3, obtained through either sunlight exposure or diet -- interact with four genes (interleukin-7 receptor-alpha, interleukin-2 receptor-alpha, MGAT1 and CTLA-4) to affect how specific sugars are added to proteins regulating the disease.

Earlier work on mice by Demetriou revealed that changes in the addition of these specific sugars to proteins engender a spontaneous MS-like disease. They also found that N-acetylglucosamine (GlcNAc), a dietary supplement and simple sugar related to glucosamine, is able to suppress this process.

The current research shows that both vitamin D3 and GlcNAc can reverse the effects of four human MS genetic factors and restore the normal addition of sugars to proteins. "This suggests that oral vitamin D3 and GlcNAc may serve as the first therapy for MS that directly targets an underlying defect promoting disease," Demetriou said.

Virtually all proteins on the surface of cells, including immune and nervous system cells, are modified with complex sugars of variable lengths and composition. This adds information to proteins separate from that directly defined by the genome. The sugars interact with specific sugar-binding proteins on the cell, forming a molecular lattice that controls the clustering, signaling and surface expression of critical receptors and transporters, such as the T cell receptor and CTLA-4. Reducing sugar modification weakens the lattice and enhances growth and activity of immune system T cells in such a way that they increase neural degeneration -- a hallmark of MS.

Production of the complex sugars is regulated by both metabolic and enzymatic functions, the latter altered by genetic MS risk factors and vitamin D3. Demetriou pointed out that the MGAT1 genetic variant linked to MS increases or decreases the sugars attached to proteins depending on metabolism -- one possible explanation for why people with the same genetic risk factor may or may not develop MS.

These sugars have also been implicated in many other chronic diseases, such as diabetes and cancer, Demetriou added, so this work could open up entirely new areas of medicine.

Haik Mkhikian, Ani Grigorian, Carey F. Li, Hung-Lin Chen, Barbara Newton, Raymond W. Zhou, Sevan Torossian, Gevork Grikor Tatarian, Sung-Uk Lee, Christine Beeton, K. George Chandy and Zhaoxia Yu of UCI and Ken Lau, Erin Walker, Katherine A. Siminovitch and James W. Dennis of the Samuel Lunenfeld Research Institute in Toronto participated in the study, which received support from the National Institute of Allergy & Infectious Diseases and the National Multiple Sclerosis Society, among others

'Dead' Galaxies Aren't So Dead After All

Individual young stars and star clusters in the 'dead' elliptical galaxy, Messier 105, detected using the Wide Field Camera 3 (WFC3) on the Hubble Space Telescope (HST). Messier 105 can be seen in the top, left corner, in an image from the Sloan Digital Sky Survey (SDSS; Data Release 8). The outlined region in the center of Messier 105 is expanded to reveal Hubble's unique view of the inner region of Messier 105, which is further expanded to unveil several individual young stars and star clusters (denoted by dashed circles; top, right). These signposts of recent star formation are unexpected in old, 'dead' galaxies. Data from HST's WFC3 and Advanced Camera for Surveys (ACS) were used in the creation of these HST images." (Credit: H. Alyson Ford and Joel N. Bregman (University of Michigan)) ScienceDaily

University of Michigan astronomers examined old galaxies and were surprised to discover that they are still making new stars. The results provide insights into how galaxies evolve with time. U-M research fellow Alyson Ford and astronomy professor Joel Bregman presented their findings May 31 at a meeting of the Canadian Astronomical Society in London, Ontario.

Using the Wide Field Camera 3 on the Hubble Space Telescope, they saw individual young stars and star clusters in four galaxies that are about 40 million light years away. One light year is about 5.9 trillion miles.

"Scientists thought these were dead galaxies that had finished making stars a long time ago," Ford said. "But we've shown that they are still alive and are forming stars at a fairly low level."

Galaxies generally come in two types: spiral galaxies, like our own Milky Way, and elliptical galaxies. The stars in spiral galaxies lie in a disk that also contains cold, dense gas, from which new stars are regularly formed at a rate of about one sun per year.

Stars in elliptical galaxies, on the other hand, are nearly all billions of years old. These galaxies contain stars that orbit every which way, like bees around a beehive. Ellipticals have little, if any, cold gas, and no star formation was known.

"Astronomers previously studied star formation by looking at all of the light from an elliptical galaxy at once, because we usually can't see individual stars," Ford said. "Our trick is to make sensitive ultraviolet images with the Hubble Space Telescope, which allows us to see individual stars."

The technique enabled the astronomers to observe star formation, even if it is as little as one sun every 100,000 years.

Ford and Bregman are working to understand the stellar birth rate and likelihood of stars forming in groups within ellipticals. In the Milky Way, stars usually form in associations containing from tens to 100,000 stars. In elliptical galaxies, conditions are different because there is no disk of cold material to form stars.

"We were confused by some of the colors of objects in our images until we realized that they must be star clusters, so most of the star formation happens in associations," Ford said.

The team's breakthrough came when they observed Messier 105, a normal elliptical galaxy that is 34 million light years away, in the constellation Leo. Though there had been no previous indication of star formation in Messier 105, Ford and Bregman saw a few bright, very blue stars, resembling a single star 10 to 20 times the mass of the sun.

They also saw objects that aren't blue enough to be single stars, but instead are clusters of many stars. When accounting for these clusters, stars are forming in Messier 105 at an average rate of one sun every 10,000 years, Ford and Bregman concluded. "This is not just a burst of star formation but a continuous process," Ford said.

These findings raise new mysteries, such as the origin of the gas that forms the stars.

"We're at the beginning of a new line of research, which is very exciting, but at times confusing," Bregman said. "We hope to follow up this discovery with new observations that will really give us insight into the process of star formation in these 'dead' galaxies."

Study Clears Protein Long a Suspect in Artery Damage

by Jennifer 

Couzin 

Measured by a simple blood test,  has vexed scientists for years. People with elevated CRP levels tend to be at higher risk of a heart attack, but does that mean the protein is causing arteries to clog and these people require medication? A study of nearly 51,000 people in Denmark says no.

Although the study is far from the last word, researchers say it will likely shift the debate about how to use CRP in guiding treatment. The work also underscores a relatively new way to uncover a single factor's influence on disease: by isolating it genetically in a large population.

CRP was discovered in 1929. Produced by the liver, it indicates inflammation in the body. For example, CRP levels surge following a trauma to tissues. People with elevated CRP levels have a higher risk of heart attack, which is caused when plaques in arteries around the heart rupture. These plaques are the hallmarks of atherosclerosis, a disease thought to be exacerbated by inflammation. People with high CRP levels are also more likely to suffer from other health problems, such as obesity and type 2 diabetes.

But no one has pinned down whether CRP is driving disease or is merely a sign of it. The distinction is crucial for understanding how atherosclerosis develops as well as determining whether CRP is a useful drug target--and whether lowering it can save lives.

To find out whether CRP promotes vascular disease, Børge Nordestgaard, a genetic epidemiologist and physician at Copenhagen University Hospital, and colleagues analyzed DNA from 50,816 participants in four large health studies. The researchers focused on four changes in the CRP gene, each of which, researchers have found, raises CRP levels. The worst combination of the four, Nordestgaard's group confirmed, boosts levels by 64%. The scientists estimated, based on earlier studies, that this group should have about a 30% higher chance of heart attacks. But there was no increased risk for them or any of the other groups carrying supposedly deleterious DNA, the team reports in the 30 October issue of the New England Journal of Medicine. The strategy is different than previous population studies of CRP, which have generally looked not at genetics but at how CRP levels correlate with heart attacks. This other approach doesn't rule out that CRP reflects existing disease or travels along with other risk factors that are the real culprits.

"Without any doubt, this tells us that CRP's not causing atherosclerosis," says Nordestgaard. He believes instead that CRP simply points to atherosclerosis that's already there.

Not everyone agrees. Paul Ridker, a cardiologist at Brigham and Women's Hospital in Boston, is testing whether lowering CRP and cholesterol can prevent heart attacks. He wants to see "direct experimental testing" that CRP doesn't cause atherosclerosis by altering levels and then determining a person's chance of a heart attack.

But cardiologist Nilesh Samani of the University of Leicester in the U.K. says that the Danish group took "a fine approach" that can be applied to other biomarkers, especially before hundreds of millions of dollars are spent to develop drugs that target a molecule that may not in fact be causing a disease. Already, researchers have tried this genetic strategy to discern the function of high-density lipoprotein, often called "good" cholesterol, and found that it has little effect on health. Still, Samani notes that CRP can still be very useful for identifying people at high risk for heart disease, particularly those without other risk factors such as high cholesterol.

Are You a Moneymaker? Look at Your Hands

by Nayanah Siva 

All in the digits. Success on the trading floor correlates with relative finger lengths.

Credit: J. Coates et al., PNAS 106 (13 January 2009)

Could the reason for the world's economic woes all come down to finger length? Although certainly an oversimplification of our current troubles, scientists have shown that financial traders who lose the biggest bucks are more likely to have shorter ring fingers than index fingers.

Previous research indicates that index-to-ring-finger (2D:4D) ratios are a good proxy for how much testosterone we were exposed to in the womb. High levels of the hormone tend to lead to growth of the ring finger and thus a low 2D:4D ratio. With increased early testosterone exposure comes increased sensitivity to the hormone in adult life--and studies have linked this heightened sensitivity to quick reactions and a willingness to take risks.

Because both are desirable characteristics for financial traders, who make minute-to-minute investment decisions, former Wall Street trader and cognitive scientist John Coates of the University of Cambridge in the U.K. wondered whether finger ratio correlated with trader success. Last year, Coates and colleagues reported that traders who experienced heightened testosterone levels in the morning made more money than traders who did not (ScienceNOW, 14 April, 2008). At the time, Coates had read that men with low index-to-ring-finger ratios had a better aptitude for sport than men with high ratios. So "for a lark," Coates says, he decided to take handprints of 44 of the young male traders he studied, all of whom worked on a fast-paced London trading floor.

Coates's hunch paid off. In the new study, reported online today in the Proceedings of the National Academy of Sciences, his team found that traders with the lowest index-to-ring-finger ratios (i.e., those exposed to more testosterone before birth) made the most money over a 20-month period, even when the researchers controlled for years of experience. They averaged the equivalent of $1,232,590, nearly six times more than that of men with high ratios. "I almost fell off my chair," says Coates. "I could not believe what I was seeing."

Tim Harford, a columnist for the Financial Times and author of The Logic of Life: The Rational Economics of an Irrational World, calls the study "fascinating." He says he's glad to see that economists have started looking at financial markets in terms of natural selection instead of looking at them in terms of rational people making rational decisions.

Coates, however, says it is important to note that this study focuses on only one type of trading, and increased confidence and quick reactions may in fact be a hindrance to those trading over long periods of time, like investors at hedge funds and investment banks. "Each style of trading may require a different set of traits," he says.

Closer Look at Einstein's Brain

by Michael Balter 

Not your average brain. Einstein's cerebral cortex has a number of unusual features that might be related to his genius in physics.

Credit: Dean Falk/S. Witelson et al., The Lancet, 353, 19 June 1999

When a rare genius like Albert Einstein comes along, scientists naturally wonder if he had something special between his ears. The latest study of Einstein's brain concludes that certain parts of it were indeed very unusual and might explain how he was able to go where no physicist had gone before when he devised the theory of relativity and other groundbreaking insights. The findings also suggest that Einstein's famed love of music was reflected in the anatomy of his brain.

When Einstein died in 1955 at Princeton Hospital in New Jersey, his brain was removed by a local pathologist named Thomas Harvey, who preserved, photographed, and measured it. A colleague of Harvey's cut most of the brain into 240 blocks and mounted them on microscope slides. From time to time, he sent the slides to various researchers, although few publications resulted. Harvey, who moved around the United States several times in the course of his career, kept the jar containing what remained of the brain in cardboard box. Finally, in 1998, Harvey--who died in 2007--gave the jar to the University Medical Center of Princeton, where it remains today.

The first anatomical study of Einstein's brain was published in 1999, by a team led by Sandra Witelson, a neurobiologist at McMaster University in Hamilton, Canada. Working from Harvey's photographs, which were all that remained of the whole brain, Witelson's team found that Einstein's parietal lobes--which are implicated in mathematical, visual, and spatial cognition--were 15% wider than normal parietal lobes. The team also found other unusual features in the parietal region, although some of these were questioned by other researchers at the time. One parameter that did not explain Einstein's mental prowess, however, was the size of his brain: At 1230 grams, it fell at the low end of average for modern humans.

Now Dean Falk, an anthropologist at Florida State University in Tallahassee, has taken another crack at the brain. Working from the same photographs and comparing Einstein's brain with a set of 25 previously published photographs and measurements of brains from cadavers, Falk claims to have identified a number of previously unrecognized unusual features in Einstein's brain. They include a pronounced knoblike structure in the part of the motor cortex that controls the left hand; in other studies, similar "knobs" have been associated with musical ability. (Einstein had played the violin avidly since childhood.)

Like Witelson's team, Falk found that Einstein's parietal lobes were larger; comparing the photographs of Einstein's brain with a second previously published set of 58 control brains, Falk also identified a very rare pattern of grooves and ridges in the parietal regions of both sides of the brain that she speculates might somehow be related to Einstein's superior ability to conceptualize physics problems. Indeed, during his lifetime, Einstein often claimed that he thought in images and sensations rather than in words. Einstein's talent as "a synthetic thinker" may have arisen from the unusual anatomy of his parietal cortex, Falk concludes in her report in press in Frontiers in Evolutionary Neuroscience.

Yet Falk concedes that her interpretation is still hypothetical. Marc Bangert, a neuropsychologist at the Max Planck Institute for Human Cognitive and Brain Sciences in Leipzig, Germany, seconds that reservation, saying, "It is very speculative, but this is what one has to deal with given the data available, some old photographs." Frederick Lepore, a neurologist at Robert Wood Johnson University Hospital in New Brunswick, New Jersey, says that Falk appears to have accurately identified a number of new features in the physicist's brain, and he finds the correlation between the motor cortex "knob" and Einstein's violin training to be "persuasive and intriguing." Nevertheless, Lepore says, he is "uneasy" with the suggestion that Einstein was a "parietal genius" who thought strictly in images and sensations, citing among other evidence his superior school grades in Latin and the sciences and mediocre marks in art and geography.

Double Amputees Shed Light on Brain's Flexibility

by Claire Thomas 

Handy. Years after a double hand transplant, this patient can perform complex tasks, including repairing an electrical wire.

Credit: PNAS

How does the brain cope when, several years after having both hands amputated, a person suddenly receives two new hands? Surprisingly well, it seems. In a study out today, researchers provide the most detailed picture yet of how the brain reorganizes itself to accommodate foreign appendages. And in a result that they are still trying to explain, the scientists found that in two such double-hand transplants, the left hand reconnected with the brain more quickly than did the right.

A group of French and Australian doctors performed the world's first hand transplant in 1998, and the same team repeated the feat on both hands 2 years later. Studies carried out since then indicate that the brain reorganizes itself in response to these new appendages. However, the work looked only at coarse hand movements that mainly used nontransplanted muscles.

Wanting to learn more about how the brain copes with donor hands, cognitive neuroscientist Angela Sirigu of the French National Research Agency in Lyon and colleagues looked at two right-handed men, one age 20 and the other 42, who recently had left and right hand transplants to replace hands amputated following work injuries 3 to 4 years ago. After extensive training, both men are now able to perform a range of complex tasks with the foreign appendages, from dialing a phone number to using tools such as screwdrivers and pliers to rewire an electrical outlet.

The researchers found that both men's motor cortexes--the region of the brain responsible for carrying out muscle movement--had reorganized themselves in response to the new hands. After a person loses a hand, the region of the motor cortex that controls hand movement shrinks and rewires itself to control the upper arm, a property called plasticity. But when Sirigu and colleagues used transcranial magnetic stimulation--a technique that employs magnetic fields to excite neurons in the brain--to stimulate specific fragments of the motor cortex, they found that the "hand areas" in the motor cortex of both men had reassumed their original "wiring." The finding, reported online today in the Proceedings of the National Academy of Sciences, shows that the brain is capable of reorganizing in quite a dramatic way in response to hand transplants, says Sirigu.

But one result baffled Sirigu's team: In both men, the left donor hand was able to connect with the brain more quickly than was the right. In the younger patient, the left hand took 10 months, and the right 26 months, to work efficiently with the brain, leaving the patient with the left as his dominant hand when performing complex tasks after transplantation. In the other patient, the left hand was able to perform complex tasks after 51 months, whereas the right still lagged behind. The results could mean that because the right hand is more dominant in these men, its representation in the brain is more rigid than the left--and thus the brain is less able to rewire control of it--says co-author Claudia Vargas, a neuroscientist who recently moved to the Federal University of Rio de Janeiro in Brazil.

Still, Sirigu cautions that it's too soon to make any concrete conclusions. The difference could result from something as simple as the way in which the surgeon reattached each hand, she says, noting that a different surgeon worked on each hand. In addition, both patients had been using advanced prosthetic right hands controlled by the nerves in the amputation stump. The motor cortex may have reorganized to accommodate the prosthetic, and this may have slowed its ability to then accept the new donor hand, says Sirigu.

Neuroscientists hail the new work as yet another demonstration of the brain's remarkable plasticity. "The results are important because they show that even after several years without a hand to control, the brain retrains the circuits necessary to control one," says neurophysiologist John Rothwell of the Institute of Neurology at University College London. And that could have "important clinical applications for rehabilitation," says neuroscientist Vilayanur Ramachandran of the University of California, San Diego.

Your Body Is a Wonderland ... of Bacteria

by Stephanie Pappas 

ENLARGE IMAGE

Microbial megalopolis. The underarm is home to a number of different types of bacteria.

Credit: Veer; Inset image courtesy of Julie Segre

Where can you find your skin's most diverse community of bacteria? Not in a sweaty armpit or linty belly button. According to a new survey of the bacterial ecosystem that covers us, the diversity hot spot of the body's exterior is the forearm. And the surprises don't end there.

Microbes that live in and on our bodies outnumber our own cells 10 to one, but researchers have only recently begun to catalog the residents on our skin. Traditionally, scientists identified human skin bacteria by swabbing volunteers and culturing the samples, but those results skewed toward microbes that grow well in the lab. Thanks to ever-evolving gene-sequencing technology, scientists can now use microbial RNA to identify organisms. With these techniques, researchers have found an unexpectedly wide variety of bacteria on human skin (Science, 23 May 2008, p. 1001). But no one had ever systematically compared bacterial colonies from different areas on the human body.

To do so, scientists from the National Human Genome Research Institute in Bethesda, Maryland, recruited 10 volunteers and asked them to wash with mild soap for 1 week. Then, after 24 hours without bathing, the volunteers arrived at the lab, where researchers swabbed and scraped their skin in 20 places--everywhere from the nostril to the navel to that bane of low-rise jeans aficionados, the gluteal crease. The team analyzed ribosomal RNA from the samples and classified the microbes based on their genomes.

The researchers found about 1000 species total, which were fairly consistent from person to person; it turns out we all have similar tenants in our noses and on our backs. The number suggests that our skin is as variegated as our guts, which house anywhere from 500 to 1000 bacterial species. The team also found vast differences across the skin, according to the study published in tomorrow's issue of Science. Contrary to what acne-prone teenagers might expect, oily areas such as the forehead and scalp are actually less diverse than dry areas such as the forearm (though one is enough for grief: Propionibacterium acnes thrives in oily spots). The most barren region was behind the ear, with a median diversity of 15 species. In comparison, the forearm teemed with a median 44 species. A follow-up with five of the volunteers months later found that bacterial makeup changed little over time.

Why some neighborhoods are more varied than others is unknown. It could be because of skin properties such as hair or oil, exposure to bacteria, or some combination. As for the forearm, geneticist and co-author Julia Segre speculates that exposed arms make a good landing pad for bacteria. Contrasted with how we clean our hands, we rarely lather up our forearms. Whatever the reason, the research shows that location matters. "This paper really highlights that the skin is an ecosystem and that the bacteria that live on our skin are not homogenous," says Segre.

The research "could contribute to explaining why certain skin diseases appear at certain sites of the body and not others," says dermatologist Richard Gallo of the University of California, San Diego. "It's a straightforward description of something that needed to be described." The next step, Segre says, is to investigate the relationship between microbial ecosystems and diseases such as eczema and psoriasis.

Does Porn Watching Lead to Divorce?

He may have been the world's most wanted terrorist at the time he was killed, but it turns out Osama bin Laden was also a typical man. Evidently, bin Laden had an "extensive" stash of porn at his compound in Abbottabad, Pakistan, according to officials.

There's no way to know if the Mrs. -- or the three Mrs. he was evidently living with -- approved of it or even knew. Most people are secretive about their porn habits. Perhaps they may have watched with him although that's doubtful; although more women are watching online porn than ever -- some 13 million American women were checking it out at least once each month in the first three months of 2007 -- they have yet to come close to guys. Women tend to favor cybersex chat rooms -- we like to talk -- while men go for the visuals.

Face it -- if there's a man in your life, he's most likely watching porn and if you're a woman, you're most likely not too happy about it.

I happen to like porn, but a lot of women get tweaked by porn in part because they think their partner is comparing them to Jenna Jameson and other porn stars; we can be competitive -- or insecure -- when it comes to other attractive women, and there's just no way most of us are going to have perfect breasts and butts, and the sexual responses a porn star does. Nor are we necessarily going to be open to all the positions and, uh, broad-mindedness of porn stars (although I'm guessing few of us would turn away, say, a Brad Pitt-George Clooney threesome; I sure wouldn't).

Polls show that we're pretty evenly divided on whether porn is just part of the package when it comes to men and if it's demeaning to women. We're also equally divided on whether porn is bad for relationships, although if you've been involved with someone who's lost interest in having sex with you because he'd prefer to jack off to some online porn, you're pretty clear on the damage it does.

Still, that's a small percentage of porn watchers. The majority of people view their porn watching as some good, not-quite-so-clean fun, according to researcher Alvin Cooper, who heads the San Jose Marital and Sexuality Center and conducts seminars on cybersex addiction. Only 15 percent of the respondents to Cooper's study said their porn watching actually led to behaviors that interfered with their lives.

But what if you happen to be married to someone in that 15 percent? Is that a good reason to dump him? What about the "recreational" porn watchers?

If you read many of the online advice boards, it seems that a lot of women are fed up with their partner's porn watching and wonder if they should get a divorce. According to research by Patrick F. Fagan, senior fellow and director of the conservative Center for Research on Marriage and Religion, pornography is a "quiet family killer."

No only does watching porn contribute to infidelity, but a spouse's porn obsession was a factor in 56 percent of divorces, Fagan says.

Divorce attorneys tend to agree with Fagan's findings. At a 2003 meeting of the American Academy of Matrimonial Lawyers, two-thirds of the 350 divorce lawyers noted that the Internet was playing an increasing role in marital splits, with excessive online porn watching contributing to more than half of the divorces. According to Richard Barry, president of the association, "Pornography had an almost nonexistent role in divorce just seven or eight years ago."

Others aren't so sure, but know something's amiss. "The attention paid to the connection between porn and infidelity doesn't translate into anything like a consensus on what that connection is," writes Ross Douthat, a senior editor at the Atlantic, in "Is Pornography Adultery?" "But if you approach infidelity as a continuum of betrayal rather than an either/or proposition, then the Internet era has ratcheted the experience of pornography much closer to adultery than I suspect most porn users would like to admit."

But is the problem porn itself or a guy's obsession with it? Or is there something else going on?

No man in a healthy sexual relationship would choose porn over bonking his flesh-and-blood partner, says San Francisco Bay Area sex therapist and America's War On Sex: The Attack on Law, Lust, & Liberty author Marty Klein. Emphasis on "healthy." So, if a guy's watching too much porn -- whatever "too" much is and who gets to decide that -- a couple now has an out; they can say he has a "porn addiction." "If a wife claims that porn use is infidelity, if a girlfriend claims that porn use means he isn't attracted to her, a disease is a good place to hide," Klein says.

So what typically happens is she puts her foot down -- "Porn or me!" -- and he promises that he'll stop watching. And some guys actually do stop, Klein says. "The rest will do what they did when they were 14 -- they'll do it in secret, feel bad about it and hope they won't get caught. And so a life of lying about sex continues. You can imagine what that will do to the couple's closeness."

Not help it, and I imagine that's how many couples find themselves divorcing over "porn addiction." What about you?

Vicki Larson

Journalist, daydreamer, freelance columnist