Science and Technology

Soccer Robots Compete For The Title

2009-04-21T06:20:00.000-07:00

At RoboCup, automated bipeds are one of many types of robots competing for the title. (Credit: Copyright Fraunhofer IAIS)

ScienceDaily (Apr. 4, 2008) — Robot soccer is an ambitious high-tech competition for universities, research institutes and industry. Several major tournaments are planned for 2008, the biggest of which is the ‘RoboCup German Open’. From April 21-25, over 80 teams of researchers from more than 15 countries are expected to face off at the Hannover Messe. In a series of soccer matches in several leagues, they will be putting the latest technologies on display.

For a machine, a soccer match is a highly complex endeavor. Robots must be able to reliably recognize the ball, the sidelines and the goalposts in addition to distinguishing between their teammates and opponents. To this end, they are outfitted with all sorts of high-tech equipment: cameras and sensors scan the robots’ surroundings, internal processors convert data to define game tactics and defense strategies, and innovative engines allow the automated players to sprint across the field and unexpectedly fake out their opponents.

There are now nine leagues, each of which has its own technological focus. In the middle-size league, robots get around on wheels. Four players and a goalkeeper compete for each team on a 20 x 14-meter pitch with standard soccer goals. They must be able to function completely independently and are equipped with internal camera systems that process information in real time. What’s more, the robots can move up to two meters per second.

Other automated soccer players, such as Sony’s robotic dog Aibo, run on four mechanical paws. And two-legged robots have been competing against each other at the RoboCup since 2005. “These humanoid robots have come a long way in recent years,” says Dr. Ansgar Bredenfeld, who is in charge of the RoboCup at IAIS. “Just like real players, they fall down and get up again, go after the ball autonomously and score goals.”

The RoboCup is more than just a soccer tournament. Since 2006, there has been a ‘RoboCup(at)Home’ category, a competition for service robots. In a replicated room, the robots must access refrigerators, collect garbage and recognize people. And in the ‘RoboCup-Rescue’ category, rescue robots must complete an obstacle course.

“RoboCup stimulates technological development in a way that wouldn’t otherwise be possible,” says Professor Stefan Wrobel, Executive Director of IAIS. “Many components that were originally designed for robot soccer have since made their way into other applications, for instance in localization technology for inspection robots.” Robots that can mow the lawn on their own or collect samples from the ocean floor for marine researchers are also equipped with RoboCup technology.

Participants under 20 years of age have their own competition, ‘RoboCupJunior’, which runs at the same time as the ‘RoboCupSenior’ tournament. In addition to fighting it out in a robot soccer tournament, the future generation of scientists will be competing in the RoboDance (robot dancing) and RoboRescue (obstacle course) competitions. These events are extremely popular: about 300 teams have registered for this year’s competition. To participate in Hannover, teams must qualify at one of three tournaments. “Germany has a serious problem: it lacks tens of thousands of engineers,” Wrobel points out. “RoboCupJunior is a very important event, as it sparks young people’s interest in technical degree courses.”

The tournament is being organized and carried out by the Fraunhofer Institute for Intelligent Analysis and Information Systems IAIS in Sankt Augustin.

Adapted from materials provided by Fraunhofer-Gesellschaft.

New Method For Monitoring Volcanoes

2009-04-21T06:11:00.000-07:00

Kamchatka, Siberia, Russia. Volcanoes emit significant amounts of sulfur dioxide. (Credit: iStockphoto/Jesús Javier Del Valle Melendo)

ScienceDaily (Mar. 13, 2009) — Seventeen of the world’s most active volcanoes have been supplied with monitoring equipment from Chalmers University of Technology in Sweden to measure their emission of sulphur dioxide. The measurement results will be used to make it easier to predict volcano eruptions, and they can also be used to improve today’s climate models.

One of the Chalmers researchers who developed the monitoring equipment is Mattias Johansson, who recently defended his doctoral dissertation in the subject.

The most active volcanoes in the world have special observatories that monitor them in order to be able to sound the alarm and evacuate people in the vicinity if an eruption threatens. These observatories keep track of several parameters, primarily seismic activity. Now 17 observatories have received a new parameter that facilitates their work – the volcanoes’ emissions of sulphur dioxide.

“Increasing gas emissions may indicate that magma is rising inside the volcano,” says Mattias Johansson at the Department of Radio and Space Science at Chalmers. “If this information is added to the other parameters, better risk estimates can be made at the observatories.”

The equipment he has been working with measures the total amount of gas emitted, whereas most other methods for metering gas can only indicate the gas concentration at a particular point. This is made possible by placing two or more metering instruments in different places around the volcano and then aggregating the information they gather.

Much of the Chalmers researchers’ work has involved making the equipment sufficiently automatic, robust, and energy-efficient for use in the inhospitable environment surrounding volcanoes, in poor countries with weak infrastructure.

“I have primarily been working with the software required for processing and presenting the measurement results,” says Mattias Johansson. “Among other things, I have created a program that analyzes the data collected, calculates the outward flow of gas, and presents the information as a simple graph on a computer screen that the observatory staff need only glance at to find out how much sulphur dioxide the volcano is emitting at any particular time.”

He has also participated in the installation of the equipment on two of the volcanoes, Aetna in Italy and San Cristobal in Nicaragua. In Project Novac, which his research is part of, a total of 20 volcanoes will be provided with monitoring equipment from Chalmers.

It will also be possible to improve global climate models when the Chalmers researchers receive continuous reports about how much sulphur dioxide is emitted by the 20 most active volcanoes.

“Sulphur dioxide is converted in the atmosphere to sulphate particles, and these particles need to be factored into climate models if those models are to be accurate,” says Associate Professor Bo Galle, who directed the dissertation. “Volcanoes are an extremely important source of sulphur dioxide. Aetna alone, for instance, releases roughly ten times more sulphur dioxide than all of Sweden does.”

The methods that Mattias Johansson has devised can moreover be used to measure the total emissions of air pollutants from an entire city. China has already purchased equipment that they are now using to study the pollution situation in the megacity Beijing.

Adapted from materials provided by The Swedish Research Council, via AlphaGalileo.

Male Circumcision Reduces HIV Risk

2009-04-21T05:50:00.000-07:00

ScienceDaily (Apr. 15, 2009) — Three recent African trials support male circumcision for reducing the risk of contracting HIV in heterosexual men. After including new data from these trials in their review, Cochrane Researchers have changed their previous conclusions that there was insufficient evidence to recommend circumcision as an intervention to prevent HIV infection in heterosexual men.

"Research on the effectiveness of male circumcision for preventing HIV in heterosexual men is conclusive. No further trials are required to establish that HIV infection rates are reduced in heterosexual men for at least the first two years after circumcision," says lead researcher Nandi Siegfried, Co-director of the South African Cochrane Centre at the South African Medical Research Council. "Policy makers can consider implementing circumcision as an additional measure into HIV prevention programmes."

Circumcision may help to protect against HIV by removing cells in the foreskin to which the virus is specifically attracted. Called Langerhans cells, they display receptors that enable HIV entry. Previous non-randomised studies investigated the association between circumcision and HIV, but until now, Cochrane researchers have been unable to make strong recommendations for the intervention due to a lack of high quality evidence gained from randomised clinical trials.

The clinical trials included in the review took place in South Africa, Uganda, and Kenya between 2002 and 2006, and included a total of 11,054 men. The results show that circumcision in heterosexual men significantly reduces their risk of acquiring HIV by 54% over a two year period, compared with uncircumcised men. This reduced risk is the best estimate of the average effect and the researchers report that the true risk will be reduced by between 38 to 66%. Further research, however, is required to establish whether male circumcision offers any benefit to women partners of circumcised men and homosexual men.

The researchers warn that policy makers also need to think about the culture and environment in which circumcision is carried out. "In many countries, male circumcision is practiced as part of the rites of initiation by traditional healers who are not trained in aseptic surgical techniques. So adverse events following traditional circumcisions can be high," says Siegfried.

Journal reference:

1. Siegfried et al. Male circumcision for prevention of heterosexual acquisition of HIV in men. Cochrane Database of Systematic Reviews Reviews, 2009, Issue 2. Art. No.: CD003362 DOI: 10.1002/14651858.CD003362.pub2

Adapted from materials provided by Wiley - Blackwell, via AlphaGalileo

7 Myths about Pregnancy

2009-04-21T00:52:00.000-07:00

A look at the science (or lack thereof) behind prenatal wives' tales
By Coco Ballantyne

1. ONLY THE MOTHER'S BIOLOGICAL CLOCK MATTERS:

Wrong. Sorry guys, but you have biological clocks, too. Scientists have long known that a woman's advancing age brings decreased fertility and increased risk of having a baby with chromosomal disorders such as Down's syndrome, says Joshua Copel, an obstetrician–gynecologist at Yale Maternal-Fetal Medicine in New Haven, Conn. (The odds of a woman under 30 having a Down's child is less than one in 1,000, but by the time she is 35, it increases to one in 400; and when she reaches 42, her chances are one in 60, according to the National Institute of Child Health and Human Development.) Men can produce sperm throughout their lives, which means they can father children at any age. But there is evidence that older dads are also more likely to pass on genetic defects to their offspring, according to Copel. Studies suggest that 2 percent of infants with dads age 50 or older will develop the neurological disorder schizophrenia—that's three times the incidence among kids fathered by men in their early 20s. And some research suggests that fathers age 40 or older are six times more likely than those under age 30 to have kids with autism spectrum disorder.

2. FAT PREGNANT WOMEN ARE MORE LIKELY TO HAVE OVERWEIGHT BABIES:

According to Robert Zurawin, an obstetrician–gynecologist (ob–gyn) at Baylor College of Medicine in Houston, overweight or obese mothers-to-be are more at risk than normal-weight ones of having big babies. The reason, he says: heavy women are more likely to have type 2 diabetes or to develop gestational diabetes (which occurs during pregnancy and usually passes after the baby is born). These diseases, in which the body has trouble using the hormone insulin, hinder cells' ability to absorb glucose, their primary energy source. As a result, the mom's blood contains excess glucose (also called high blood sugar), which passes to the fetus via the placenta, says Zurawin, adding "It's like the baby's eating ice cream all day long."

3. BUMP IN THE FRONT? IT'S A BOY:

If the fetus is male, the mom carries most of the weight low and in the front, like a basketball shooting from her hips; if it's a girl, the mother looks more like a planet, round all over—or so they say. "That's clearly a myth," says George Saade, chief of maternal-fetal medicine at The University of Texas Medical Branch (U.T.M.B.) in Galveston. How much the belly sticks out depends largely on how far the abdominal muscles flanking the left and right sides of the belly separate and relax, leaving a gap without muscle through which the uterus can bulge forward under the skin, Saade explains. And how high or low the belly sits depends on how much the pelvic joints loosen (thanks to a hormone called relaxin, produced by the ovaries mainly during pregnancy), thereby making more room for the baby to drop into the pelvis, he adds. Another factor influencing belly shape, he says, is the position of the fetus, which varies throughout pregnancy. The belly will appear wider, for instance, if the fetus is lying horizontally rather than vertically.

4. PREGNANT WOMEN SHOULD AVOID PEANUTS BECAUSE THEY UP THE BABY'S ODDS OF DEVELOPING AN ALLERGY TO THEM

There is no compelling scientific evidence that eating peanuts, shellfish or other potentially allergenic foods during pregnancy affects the baby's risk of developing allergies, according to Aziz Sheikh, a community health scientist at the University of Edinburgh in Scotland who has studied childhood allergies. U.T.M.B.'s Saade concurs. "For an allergen to affect the baby during pregnancy," he says, "it has to get into the mother's [blood] and then cross the placenta in a form that remains allergenic." But, he notes, the mother's metabolism might break down food allergens into nonallergenic components (such as amino acids and short chains of amino acids) before entering her bloodstream and reaching the fetus.

5. A FETUS WITH A FULL HEAD OF HAIR SPELLS HEARTBURN FOR MOM:

A few years ago, researchers from Johns Hopkins University (J.H.U.) in Baltimore decided to put this myth to rest with a scientific study, but they didn't get the results they were expecting. The researchers asked 64pregnant women—all in their third trimester—to rate the severity of their heartburn, and then compared the hair volumes of their infants within two weeks of birth. Their findings, published in the journal Birth: 23 out of 28 (82 percent) of the women reporting moderate or severe heartburn gave birth to babies with average or above average amounts of hair; only 11 out of 36 (31 percent) of those with mild or no heartburn produced babies with luxuriant locks. Study co-author Janet DiPietro, a developmental psychologist at the J.H.U. Bloomberg School of Public Health, cautions that the study was small and does not establish a definitive link between heartburn and fetal hair. But if there is one, she suspects pregnancy hormones such as estrogen and progesterone might be to blame. She says the same hormones that stimulate fetal hair growth might also relax the esophageal sphincter, the muscle in the esophagus that normally tightens after meals, allowing stomach acids to flow up into the esophagus and cause heartburn (acid reflux).

6. LIFTING HEAVY OBJECTS COULD CAUSE THE PLACENTA TO RIP FROM THE UTERINE WALL:

Lifting something cannot not cause the placenta to shear from the wall of the womb, cutting off the supply of nutrients and oxygen to the fetus, Saade says. The concern with lifting, he says, is that the mother could injure her back or lose balance and topple over. Being pregnant, especially during the final months, is like carrying a bag full of groceries all day—extra weight in the front that shifts the woman's center of gravity and makes it harder to balance, thereby putting stress on the spine, along with increasing her risk of falling. Lifting something heavy only adds more to that stress, Saade notes, upping the chance of back injuries such as pulled muscles.

7. WOMEN EAT MORE WHEN EXPECTING A BOY:

In 2003 a team of researchers from the U.S. and Europe studied the diets of 244 pregnant women during their second trimester and found that those carrying male fetuses ate, on average, 190 more calories per day than those carrying females. Those extra calories apparently made a beeline for the fetus, because the boy babies were heavier and their mothers did not pack on any more pounds than those carrying girls. "We found that birth weight of boys was on the average higher than that of girls," says senior author Dimitrios Trichopoulos, an epidemiologist at the Harvard School of Public Health in Boston. "Our interpretation is that boys are somehow programmed to be heavier than girls, and this requires higher caloric intake from the mother," he adds, speculating that testosterone from the fetal testicles might be involved in increasing the maternal appetite. (http://www.sciam.com/slideshow.cfm?id=slideshow-7-pregnancy-myths)

How Google Is Making Us Smarter

2009-04-21T00:21:00.000-07:00

Humans are "natural-born cyborgs," and the Internet is our giant "extended mind."
by Carl Zimmer

From the February 2009 issue, published online January 15, 2009

Our minds are under attack. At least that’s what I keep hearing these days. Thumbing away at our text messages, we are becoming illiterate. (Or is that illiter8?) Blogs make us coarse, YouTube makes us shallow. Last summer the cover of The Atlantic posed a question: “Is Google Making Us Stoopid?” Inside the magazine, author Nicholas Carr argued that the Internet is damaging our brains, robbing us of our memories and deep thoughts. “As we come to rely on computers to mediate our understanding of the world,” he wrote, “it is our own intelligence that flattens into artificial intelligence.”

I have a hard time taking these Cassandras of the Computer Age seriously. For one thing, they are much more interested in our fears than in the facts. In his new book, Txtng: The Gr8 Db8, the English linguist David Crystal demonstrates that many of the dire warnings about texting are little more than urban legends. Texting doesn’t lead to bad spelling, he finds. In fact, Crystal writes, “texting actually improves your literacy, as it gives you more practice in reading and writing.”

More significantly, the ominous warnings feed on a popular misconception of how the mind works. We tend to think of the mind as separated from the world; we imagine information trickling into our senses and reaching our isolated minds, which then turn that information into a detailed picture of reality. The Internet and iPhones seem to be crashing the gate of the mind, taking over its natural work and leaving it to wither away to a mental stump. As plausible as this picture may seem, it does a bad job of explaining a lot of recent scientific research. In fact, the mind appears to be adapted for reaching out from our heads and making the world, including our machines, an extension of itself.

This concept of the extended mind was first raised in 1998, right around the time Google was born, by two philosophers, Andy Clark, now at the University of Edinburgh, and David Chalmers, now at the Australian National University. In the journal Analysis, they published a short essay called “The Extended Mind” in which they asked a simple question: “Where does the mind stop and the rest of the world begin?” Most people might answer, “At the skull.” But Clark and Chalmers set out to convince their readers that the mind is not simply the product of the neurons in our brains, locked away behind a wall of bone. Rather, they argued that the mind is something more: a system made up of the brain plus parts of its environment.

Clark and Chalmers asked their readers to imagine a woman named Inga. Inga hears from a friend that there’s an exhibit at the Museum of Modern Art. She decides to go see it. She thinks for a moment, recalls that the museum is on 53rd Street, and starts walking that way. She accesses her belief that MOMA is on 53rd Street from its storage place in her brain’s memory network. Now imagine a man named Otto, who has Alzheimer’s. His memory is faulty, and so he keeps with him a notebook in which he writes down important details. Like Inga, Otto hears about the museum exhibit. Since he can’t access the address in his brain, he looks it up in his notebook and then heads off in the same direction as Inga.

The mind appears to be adapted for reaching out and making the world, including our machines, an extension of itself.

In the view of Clark and Chalmers, Inga’s brain-based memory and Otto’s notebook are fundamentally the same. Inga’s mind just happens to access information stored away in her brain, while Otto’s mind draws on information stored in his notebook. The notebook, in other words, is part of his extended mind. It doesn’t make any difference that Otto keeps his notebook tucked away much of the time. After all, Inga tucks the memory of MOMA’s address out of her conscious awareness most of the time too. Clark and Chalmers concluded that real people are actually more like Otto than like Inga: We all have minds that extend out into our environments.

Eleven years later, this argument continues to trigger fierce debate among philosophers, psychologists, and neuroscientists. There is no doubt that the extended mind is a weird concept. One reason it seems so strange is that our minds feel as if they are really totally self-contained. We innately believe, for example, that as we walk down a street, we are continuously filming a detailed movie of our surroundings and using that mental movie to decide what to do next. But like many beliefs we have about ourselves, this movie is an illusion. Our awareness is, in fact, remarkably narrow.

One of the most spectacular demonstrations of how oblivious we can be was carried out by psychologists Daniel Simons of the University of Illinois and Christopher Chabris at Harvard University. They asked people to watch a video of students weaving around each other and passing a basketball. Half the students wore white shirts, the other half black. The subjects had to keep track of how many times the ball was passed by members of one of the teams. In the middle of the game, a gorilla (rather, a student in a gorilla costume) sauntered through the scene. Many subjects later reported that they never saw the gorilla; their brains discarded it as extraneous.

Inside our heads, instead of making a perfect replica of the world, we focus our attention on tiny snippets, darting our eyes from point to point. We extract only the information we need for whatever task is at hand, whether we’re sorting the laundry or climbing a mountain.

We use strikingly little information in the process. Dana Ballard, a computer scientist at the University of Texas, developed a computer game to measure just how little. He showed his subjects a pattern of colored blocks in the upper left-hand corner of the computer monitor. He then had them build a similar pattern of blocks in the lower left-hand corner. To do so, the players used a mouse to grab blocks, one by one, from a collection on the right-hand side of the screen. As the players looked from the original model to the collection of blocks to their own growing pattern, Ballard tracked their eye movements. He found that players looked at the model at the upper left before they picked up a block, and then again afterward. His experiments suggest that in each glance, the players were storing only a single piece of information. The first time they noted a block’s color. The second time they noted its position in the model. Instead of keeping a detailed picture of the blocks in mind, people extracted just tiny scraps of information on a need-to-know basis.

Clark argues that Ballard’s subjects made the pattern of blocks part of their extended mind. It became a store of knowledge they could dip into, an external repository of information. It was as if Inga did not actually recall the address of MOMA but only the page in her notebook where she had written it down. Our memory holds a great deal of information. But the extended mind moves swiftly between outside and inside sources, showing little regard for where its information comes from.

Our minds do more than take in information, of course. They also make decisions and send out commands—and those commands certainly don’t stay inside the mind. In the block-building game, for example, some commands go to neurons in the hand in order to move the computer mouse. But our brains don’t make a perfect mental replica of our hands and the mouse and the table in order to calculate where the mouse needs to go. Our hands and eyes constantly send signals to the brain, and that feedback alters the signals coming back out. Hand, eye, and brain are part of the same system.

We will soon be able to enhance our brains with drugs or implants. But changes we make to the environment already alter our minds.

What’s even more remarkable about our brains is that they actually search for new things to make part of this feedback system. Imagine you are poking a stick into an animal’s burrow. As you poke away, you are aware of what the far end of the stick is touching, not the end you’re holding in your hand. This kind of extended sensation appears to be the result of a reorganization of the brain. Scientists have found that when test monkeys spent five minutes learning how to use a rake, some of the neurons in their hands began behaving in a new way. They began to fire in response to stimuli at the end of the rake, not on the monkey’s hand. Other neurons, in the brain, respond to things that appear to lie within arm’s reach. Training the monkeys to use the rakes caused these neurons to change—reacting to objects lying within rake’s reach rather than arm’s reach. (http://discovermagazine.com/2009/feb/15-how-google-is-making-us-smarter/article_view?b_start:int=1&-C=)

Mom and Dad Are Fighting in Your Genes—and in Your Brain

2009-04-21T00:15:00.000-07:00

Our brains may contain a battle of the sexes that can cause schizophrenia and autism.

by Carl Zimmer

From the December 2008 issue, published online November 10, 2008

Sometimes the best way to learn how the brain works is to watch what happens when it goes awry. When one part—a clump of neurons or a brain-building gene—doesn’t do what it is supposed to, the brain may fail in an illuminating way. Its failure may even expose some of the hidden foundations of the mind.

Neuroscientists have recently become fascinated with a particularly telling pair of rare brain disorders. One was identified in 1965 by English physician Harry Angelman, who was struck by the faces of three children he treated. These children were always smiling and often laughing. This disorder, now known as Angelman syndrome, affects around 1 in 20,000 children. Along with the smiles and laughs come other symptoms, some of which overlap those of severe autism. Many children with Angelman syndrome never learn to speak or read. They also keep their bodies in motion, often flapping their hands. When they nurse they suckle desperately, thrusting out their tongue.

Another similarly rare condition, called Prader-Willi syndrome, produces a different set of symptoms. Babies with Prader-Willi nurse very little—so little that they often have to be tube fed. However, once Prader-Willi children get to be a few years old, they develop an insatiable appetite. They will try to get around any obstacle put between them and food. Their fierce hunger is driven by a malfunctioning hypothalamus, a region deep in the brain that governs hunger and growth. Instead of autism, many people with Prader-Willi syndrome develop schizophrenia by adulthood, hearing voices and generating paranoid delusions.

Despite their differences, Prader-Willi and Angelman are two sides of the same coin. Scientists have searched for the genetic basis of the two syndromes and have tracked most cases of both to defects on the same spot of the human genome, a stretch of DNA on chromosome 15. Which disease a child gets depends on which parent’s chromosome 15 carries the defect (every person’s cells contain two genetic copies, one from the mother and one from the father). Prader-Willi syndrome is caused by a mutation in a father’s genes that deletes a chunk of DNA on chromosome 15. Angelman syndrome is associated with a mutation on the mother’s chromosome 15.

If you think back to the genetics you learned in school, this pattern makes no sense. A gene is a gene is a gene. Two identical stretches of DNA ought to have the same effect on a child, regardless of which parent it comes from. But sometimes our genes break the rules of high-school genetics. The effects of dozens, perhaps hundreds, of genes depend on whether you inherited them from your mother or your father.

Dissimilarities arise because not all genes are actively expressed in our cells. Some of the genes get switched off, or silenced. Each time a cell divides and makes a new copy of its DNA, special enzymes attach caps at certain spots along the copy’s length. Those caps make it impossible for a cell to read the specific genes they are attached to. As a result, those genes can’t make the corresponding proteins. In some cases the caps are attached to only one parent’s copy of a gene. The other parent’s copy remains uncapped, free to produce proteins.

This parental silencing is known as gene imprinting, and it is turning out to be important to our health. Mutations that change the pattern of imprinting can have a big effect on our bodies. If a cell fails to imprint one of the two parents’ genes, for example, it will have two genes producing a protein instead of just one. The cell will make twice as many copies of the protein.

The discovery of gene imprinting in 1984 raised a big question: Why should genes from one parent be silenced in the first place? In 1999, David Haig of Harvard University offered a startling hypothesis. Gene imprinting, he proposed, is the result of the evolutionary struggle between mothers and fathers for reproductive success. This fight doesn’t take place between mothers and fathers themselves but between the genes that they pass down to their offspring. Natural selection favors genes that can make more copies of themselves. But the best strategy for the genes of fathers is not the same as the one that’s best for the genes carried by mothers.

For millions of years, mothers have had to invest a huge amount of time and effort in their children. The investment starts in the womb as mothers supply growing fetuses with nutrients.

Haig noted that the demands of reproduction have forced mothers into an evolutionary trade-off. If they invest a lot in one child, he or she gets bigger and healthier and more likely to survive to adulthood. But investing too much in one child can undermine the well-being of any siblings and can put a mother’s own health at risk. The most successful solution is to invest a lot—but not too much—in each child.

Fathers do not face this trade-off. As a result, natural selection should favor a different strategy for their genes. From a dad’s perspective, the more nutrients his child can get from the mother, the more likely it is that the child will grow up healthy and pass on his or her father’s genes.

Haig argued that the process of natural selection would favor mutations in the genes of fathers that boost the amount of nutrition babies get from their mothers. The genes might govern the speed at which a fetus grows, or they might make the placenta more aggressive as it penetrates the mother’s tissues.

As fathers passed down these growth-stimulating genes, Haig continued, mothers would benefit from counterstrategies. They might evolve genes that slow the rapid growth of their children, in order to preserve their own long-term health. Moms could also evolve to imprint (deactivate) their copies of the genes that increase growth. Haig’s imprinting hypothesis still generates a lot of debate, but there is now considerable evidence to back it up.

Autism and schizophrenia may be partly the result of conflicts between parental genes.

What is particularly remarkable about imprinted genes is that a lot of them play a role in shaping the brain. Some of them, in fact, are active only in the brain. How could the conflict between mothers and fathers play out in our heads? Two evolutionary biologists, Bernard Crespi of Simon Fraser University in Canada and Christopher Badcock of the London School of Economics and Political Science, have been exploring imprinting disorders like Angelman and Prader-Willi syndromes to get some clues. They have come up with a bold idea: Our minds, too, are shaped by conflict between our parents’ genes. (http://discovermagazine.com/2008/dec/10-mom-and-dad-are-fighting-in-your-genes-and-your-brain/article_view?b_start:int=1&-C=)

Numbers 78 Exabytes of Facebook, Porn, and More

2009-04-21T00:02:00.000-07:00

The big numbers behind Internet use in the U.S.

by Adam Hadhazy

From the May 2009 issue, published online April 19, 2009

78,000,000,000,000,000,000 (78 quintillion bytes, or 78 exabytes)
Number of bytes (which can represent a single number or letter) sent over the Internet last year, according to University of Minnesota researchers. Internet traffic is growing at an annual rate of 50 to 60 percent.

$214.4 BILLION
Total e-commerce spending in the United States in 2008, the Internet research firm comScore reports. Online spending increased 7 percent last year—nothing like the years immediately prior, which saw growth rates near 20 percent.

1,122,311
Number of trojans, worms, viruses, and other types of malicious code identified by Internet security company Symantec in a recent report. A total of 5,060,187 bot-infected computers, which can be remotely controlled to send out spam, were running in late 2007. The Sophos Internet security firm discovered a new infected Web page every 4.5 seconds, on average.

34,916,000,000
Number of minutes Internet users in the United States spent viewing social networking Web sites such as Facebook and MySpace in January 2009 alone, according to comScore. That is 10 percent of all minutes spent online.

5.47
Number of subscriptions to adult-content sites per 1,000 households with broadband access in Utah, the state with the highest rate of subscriptions, according to a paper in the Journal of Economic Perspectives. Montana has the lowest rate, with 1.92 per 1,000 households. Thirty-six percent of Internet users visit at least one adult Web site per month, comScore reports. (http://discovermagazine.com/2009/may/78-exabytes-of-facebook-porn-and-more)

Eyes in the Sky Show That Air Pollution Is Way Worse Than We Thought

2009-04-20T23:02:00.000-07:00

New satellite tracking gives a much more accurate read on global air pollution.
by Boonsri Dickinson

From the May 2009 issue, published online April 13, 2009

Particulate air pollution is typically measured at ground level. Unfortunately, many of the world’s most polluted areas are in developing countries that cannot afford extensive monitoring. To remedy this, Sundar Christopher, an atmospheric scientist at the University of Alabama at Huntsville, compared satellite data with ground measurements in well-studied areas. Using those comparisons, he devised a way to determine surface air quality using satellite data alone. “Remote sensing is the only viable way to monitor global particulate matter,” he says. Using NASA’s Terra and Aqua satellites, he and his team examined 20 cities with populations greater than 10 million. In 15 of them, pollution levels were five to ten times higher than the World Health Organization’s guidelines. The researchers are now using satellites to track how pollution moves from one region to another.

Meanwhile, on the ground, other scientists have found new ways to track refinery pollution. Environmental engineer Shankar Chellam of the University of Houston placed filters around his city to collect metals released by oil refineries. The highest pollutant concentrations occurred on days when refineries reported equipment problems, suggesting they are the source. Chellam will analyze pollution contributions from other industries and from vehicles to provide policymakers with data needed to create more effective regulations. (http://discovermagazine.com/2009/may/13-eyes-in-sky-show-air-pollution-is-much-worse)