drd4 6.drd.0 Louis J. Sheehan, Esquire

A gene thought by some scientists to foster a bold, novelty-seeking personality, as well as attention-deficit hyperactivity disorder (ADHD), apparently spread substantially in human populations over roughly the past 40,000 years, according to a new study.

One form of the gene gained evolutionary favor near the end of the Stone Age because it enhanced survival and reproduction, proposes a team led by biologist Yuan-Chun Ding of the University of California, Irvine. The form is now the second-most-prevalent variant of the so-called DRD4 gene, which codes for a type of dopamine receptor (DRD4) found on brain cells.

Ding's team theorizes that prehistoric people who trekked from Africa to distant locales may have relied on nervy, intrepid individuals to lead the journey. Many bearers of this variant of the DRD4 gene would have had the requisite personalities to head up migrating groups, Ding's group asserts in the Jan. 8 Proceedings of the National Academy of Sciences.

To study variations in this gene, the researchers scrutinized the DNA sequence of the gene in 600 adults from Africa, Asia, Europe, the Americas, and the Pacific.

The most common DRD4 arrangement�found in about two-thirds of people�differs slightly from several less prevalent variations of the gene, the researchers say.

In contrast, the novelty- and ADHD-linked form of the gene diverges markedly from the most common pattern. It's likely that this version of the DRD4 gene, which occurs in a sizable minority of people worldwide, resulted from one or more unusual mutations of the common form and then increased in frequency as the Stone Age wound down, around 40,000 years ago, Ding and his coworkers theorize.http://Louis-j-sheehan.com

Although this gene conferred advantages in prehistoric times, it appears to stoke childhood behaviors that now get diagnosed as ADHD, the researchers add.

Nonetheless, in an earlier study, they found that children with ADHD who possess this particular form of the DRD4 gene do much better on attention tests than ADHD kids with different versions of the gene do. Louis J. Sheehan, Esquire .

Other scenarios may explain the spread of this specific DRD4 gene, say Henry Harpending of the University of Utah in Salt Lake City and Gregory Cochran of the research firm Reconstruction Concepts in Albuquerque, N.M., in a comment published with the new study. For example, the prehistoric advent of societies in which women produced most of the food would have left men with lots of time to compete for mates. In these groups, a gene facilitating risky "show-off" behaviors in men would have proliferated, the anthropologists suggest.http://Louis-j-sheehan.com

first 3.fir.002889 Louis J. Sheehan, Esquire

Soon, every single American will have a digital avatar—and we’re not talking about Second Life characters. Researchers at Virginia Tech are building a nationwide computer simulation that will include 300 million synthetic individuals with true-to-life characteristics taken from U.S. Census data. The researchers say there are many uses for the simulation, from predicting the spread of infectious diseases to tracking fads and modeling traffic flow. http://www.myspace.com/louis_j_sheehan_esquire




The program, known as EpiSimdemics, already has 100 million simulated residents.
http://louis-j-sheehan-esquire.blog.friendster.comEach resident is endowed with as many as 163 variables, including age, education, occupation, family size, and general health. Although each synthetic resident isn’t meant to represent a specific real-life person, the information is taken from publicly available demographics data. The residents are mapped to real houses and real neighborhoods and assigned local schools, grocery stores, and shopping centers. The researchers hope to add more variables, including air travel using real-life flight data. http://louis-j-sheehan-esquire.blog.friendster.com/



One of the first uses will be to study the spread of infectious diseases like the flu. Since the program can model the movements of the residents and their interactions with each other, by seeding a few residents with a virus, the program will simulate how the virus spreads, even taking into account the progress of the disease in each person. http://myface.com/Louis_J_Sheehan




But the researchers have bigger plans for their virtual reality nation: “The vision is for a Google-like interface, where you approach the system and ask it a question,” says researcher Christopher Barrett. “The framework is there, and now we’re pushing the system to larger and larger scales.” Louis J. Sheehan, Esquire

rocks 4.roc.0002 Louis J. Sheehan, Esquire

New research explains why a cancer-causing form of chromium has been turning up in ground and surface waters far from industrial sources. http://www.soulcast.com/Louis3J3Sheehan/

Chrome plating and dye manufacturing are among the industries that generate chromium (VI), a form that the element assumes in certain compounds. But recently, researchers have discovered the toxic agent in regions—including California and parts of Mexico and Italy—beyond the reach of industrial contamination.

In these cases, "it was obvious that [chromium (VI)] had to be coming from a natural material," says Scott Fendorf, an environmental chemist at Stanford University.

Fendorf and his coworkers focused on the mineral chromite, found in certain rocks and soils common to the Pacific coasts and other seismically active areas. Over time, chromite slowly releases chromium (III), a relatively benign form of the element.

The researchers reacted chromite with birnessite, a manganese-containing mineral that often forms in weathered rocks and soils containing chromite. In water, powders of the two solids produced chromium (VI). "Both minerals tend to be fairly insoluble, but they dissolved just enough" to react, says Fendorf. http://www.soulcast.com/Louis3J3Sheehan/

The researchers conclude that within 100 days, chromite and birnessite could generate chromium (VI) at concentrations above the World Health Organization's limit for drinking water—which is 50 micrograms per liter. In acidic conditions, such concentrations could be reached in fewer than 10 days, the team reports in the April 17 Proceedings of the National Academy of Sciences.

The work indicates that certain chromite-rich regions are at high risk for natural chromium (VI) generation. "You need to watch the groundwater pretty closely in these areas," Fendorf says. Louis J. Sheehan, Esquire

Brighten 77.bri.2222000 Louis J. Sheehan, Esquire

Louis J. Sheehan, Esquire . A distressingly large number of children suffer physical or sexual abuse. A new study adds a genetic twist to the much-noted tendency of maltreated kids to become violent, law-breaking adults.http://www.myspace.com/louis_j_sheehan_esquire

Abused boys who inherited a highly active version of one gene crucial in brain chemistry later had far fewer behavioral problems and arrests for violent crimes than did abused boys who were born with a sluggish version of the same gene, say psychologist Avshalom Caspi of King's College in London and his colleagues.

"There's an interplay between two variations of this gene and the experience of childhood maltreatment," remarks King's College psychologist Terrie Moffitt, a study coauthor. "One genetic variation may protect abused boys from converting their stressful experiences into antisocial behavior toward others."http://www.myspace.com/louis_j_sheehan_esquire

Individual differences in the gene for monoamine oxidase A, or MAOA, proved critical for maltreated boys tracked up to age 26, the scientists report in the Aug. 2 Science. Situated on the X chromosome, the MAOA gene yields an enzyme that lowers brain concentrations of chemical messengers such as norepinephrine, serotonin, and dopamine.

Earlier studies had linked genetic deficiencies in MAOA production to extreme aggression in mice and in men of a Dutch family.

Caspi's team probed the molecular structure of MAOA genes in 442 young men in New Zealand who had been studied since age 3 (SN: 4/15/95, p. 232). By age 11,

36 percent of the boys had experienced some form of maltreatment, including physical and sexual abuse and frequent shuttling from one caretaker to another.

Although only 12 percent of maltreated boys possessed the low-activity MAOA gene, Caspi found, they account for nearly half of all later convictions for physical assault and other violent crimes.

Moreover, 85 percent of severely maltreated boys with the low-activity MAOA gene developed antisocial behavior by young adulthood. Antisocial behavior includes persistent fighting, bullying, stealing, and law breaking with no sign of remorse.

In contrast, antisocial behavior and criminal arrests occurred in only a minority of maltreated males who had inherited the highly active MAOA gene. High MAOA activity may promote "trauma resistance," even though the boost doesn't make all maltreated boys solid citizens, Moffitt contends.

Compared with the males, females in the same study showed a significant but less dramatic effect of the MAOA gene on the linkage between childhood maltreatment and later antisocial behavior. One reason that females engaged in less of such behavior than males did may be that, by having two X chromosomes, girls more often inherited at least one copy of the high-activity MAOA gene, Moffitt theorizes.

The new findings open the door to identifying biological mechanisms that connect childhood maltreatment to ensuing behavior problems, comments psychologist Seth D. Pollak of the University of Wisconsin�Madison. "And when you have a mechanism, you can begin to design effective treatments," he says. Louis J. Sheehan, Esquire

memory kids 6663.mem.23 Louis J. Sheehan, Esquire

The second year of life may be particularly memorable. Around the time of their first birthday, children make dramatic advances in remembering simple events for 4 months after witnessing them, a new study finds. This memory breakthrough depends on a proliferation of neural connections in memory-related brain structures known to develop as infants approach age 1, propose Harvard University psychologists Conor Liston and Jerome Kagan.LOUIS-J-SHEEHAN.INFO

The researchers recruited 12 babies and toddlers at each of three ages: 9 months,

17 months, and 24 months. Children watched an experimenter both perform and describe three action sequences. In one sequence, for example, the experimenter said "Clean-up time!" while wiping a table with a paper towel and then throwing the towel into a trash basket. Louis J. Sheehan, Esquire

Kids in the two older groups watched four demonstrations of each action sequence, and 9-month-olds saw six repetitions. After each presentation, the experimenter encouraged children to imitate what they had just seen.

Four months later, the youngsters�then ages 13 months, 21 months, and 28 months�were asked to reenact each set of actions with the same materials after hearing the same verbal descriptions.LOUIS-J-SHEEHAN.INFO

The children now 28 months old correctly performed a majority of previously observed actions, usually in their original order, Liston and Kagan report in the Oct. 31 Nature. The 21-month-olds reenacted what they had seen almost as well as their older peers did. Far fewer signs of accurate recall appeared in 13-month-olds, the only participants who had been under 1 year of age during initial memory trials. Louis J. Sheehan, Esquire

Honda 883.hon.2221 Louis J. Sheehan, Esquire

Louis J. Sheehan, Esquire. Honda’s robotics division has unveiled the prototype of a strange new helper: a “walking assistant.” Honda says the robotic legs could restore mobility to the elderly or infirm, and could help prevent factory workers from straining their muscles–if they don’t mind being joined to the strange looking device. The user would employ the device by stepping into a pair of shoes attached to jointed legs. The legs support a mildly-scary looking U-shaped saddle, which cups the wearer’s groin and buttocks firmly to deliver solid uplift…. Honda say that the machine reduces load on the hip joints, and helps not just with walking but also standing - and especially with maintaining a crouched position [The Register]. http://www.soulcast.com/Louis3J3Sheehan/

The device, which weighs about 14 pounds and is powered by a motor and Lithium ion battery, is the result of Honda’s nine-year-old initiative to develop mobility-assisting technologies. The creation of the device borrowed heavily from the walking research that went into Honda’s advanced humanoid robot, ASIMO [Daily Tech]. Honda hasn’t yet announced plans to begin selling the walking assistants, but tests of the prototype will begin this month.

Honda plans to test out the device on workers in its Saitama car factory, and says the devices could be a great boon to workers who crouch down along the assembly line. http://www.soulcast.com/Louis3J3Sheehan/ And while the robotic legs aren’t suitable for paraplegics or people with serious muscle control issues, they could give a necessary boost to people with weak leg muscles, or patients recovering from accidents or surgery. http://www.soulcast.com/Louis3J3Sheehan/

The need for such mechanical help is expected to grow in Japan, which has one of the most rapidly aging societies in the world. Other companies are also eyeing the potentially lucrative market of helping the weak and old get around. Earlier this year, Japanese rival Toyota Motor Corp. showed a Segway-like ride it said was meant for old people. Japanese robot company Cyberdyne has begun renting out in Japan a belted device called HAL, for “hybrid assistive limb,” that reads brain signals to help people move about with mechanical leg braces that strap to the legs. Louis J. Sheehan, Esquire

ash 6655.9o Louis J. Sheehan, Esquire

Louis J. Sheehan, Esquire. Scientists now have geochemical clues about the composition of volcanic ash used in Maya pottery between the 7th and 10th centuries, though the ash’s source is still a mystery. Results of a new study definitively discount one Mexican volcano, long thought to be the likely supplier of the ash.http://Louis2J2Sheehan2Esquire.US

Researchers have long known that Maya of the Late Classic period, an archeological interval that stretched approximately from 600 to 900, used a mixture of volcanic ash and clay to make pottery. http://Louis2J2Sheehan2Esquire.US Microscopic analyses of broken potsherds show that the ash particles are sharp-edged, indicating they were freshly erupted when the pots were made, says Brianne Catlin, a geoarchaeologist now at Hess Corp. in Houston. While at the University of California, Santa Barbara, she and her colleagues analyzed pottery fragments found at El Pilar, a Maya site near the Belize-Guatemala border, in an attempt to find the source of the pottery’s ash.

Very little soil covers the carbonate bedrock at El Pilar, and all of the ash layers found there are too old and chemically degraded to have supplied the ash used in the pottery, Catlin reported Monday in Houston at the annual meeting of the Geological Society of America. Because the Maya pottery typically is both heavy and fragile, it’s unlikely that such items were imported. Instead, she speculates, ash was hauled in for local potters from other areas at great effort — especially considering the Maya had no roads, no pack animals and would have needed to import several tons of the material each year to produce enough everyday dishes and pottery for the site’s thousands of residents.

To see how various combinations of temperature and heating times affected the chemical composition of ash in pottery, Catlin and her colleagues fired pots using a 50-50 mixture of clay from the El Pilar site and volcanic ash of known chemical composition from California. In the tests, for example, the longer the pottery was fired, the more sodium was driven from the material. The hotter the firing temperature, the higher the calcium concentration became. Finally, the firing process didn’t affect the silica content of the pottery at all, Catlin notes.

The ash in the potsherds found at El Pilar is about 78 percent silica, the researchers found. That’s distinctly different than the composition of ash from El Chichón volcano, which lies about 375 kilometers west of El Pilar and spews ash that’s about 58 percent silica. Some archaeologists have suggested that material lofted from El Chichón was used in the Maya pottery, because an ash plume from a 1982 eruption wafted eastward and fell on El Pilar, but the new results don’t support that notion, says Catlin.

She and her colleagues are now analyzing ash from several volcanoes that lie between 350 and 400 kilometers southwest of El Pilar, to see if material spewed from those peaks has a chemical composition that matches the ash used in the Maya pottery. Besides being about 78 percent silica, that ash probably had a 0.4 percent concentration of calcium, the team’s tests suggest.Louis J. Sheehan, Esquire