- Research Reveals Early Signs of Autism in Some Kids
- Big Earthquakes Cause Premature Births
- Video: Cold, Little Comet Is No Match for Big, Hot Sun
- Solar Slumber May Have Been Caused by Magnetic Flows
Posted: 12 Mar 2010 02:41 PM PST
BALTIMORE — Some infants headed for a diagnosis of autism, or autism spectrum disorder as it's officially known, can be reliably identified at 14 months old based on the presence of five key behavior problems, according to an ongoing long-term study described March 11 at the International Conference on Infant Studies.
These social, communication and motor difficulties broadly align with psychiatric criteria for diagnosing autism spectrum disorder in children at around age 3, said psychologist Rebecca Landa of the Kennedy Krieger Institute in Baltimore. In her investigation, the presence of all five behaviors at 14 months predicted an eventual diagnosis of autism spectrum disorder in 15 of 16 children.
"That's much better than clinical judgment at predicting autism," Landa noted.
Her five predictors of autism spectrum disorders among 14-month-olds at high risk for developing this condition include a lack of response to others' attempts to engage them in play, infrequent attempts to initiate joint activities, few types of consonants produced when trying to communicate vocally, problems in responding to vocal requests and a keen interest in repetitive acts, such as staring at a toy while twirling it.
Accurate identification of infants likely to develop autism spectrum disorder by age 3 is particularly important because studies at Landa's facility and several others indicate that intensive interventions with youngsters who display early warning signs and their parents often yield marked behavioral improvements. Interventions focus on teaching kids basic interaction and communication skills.
Landa's study consists of 250 children who were first assessed at either age 6 months or 14 months. Comprehensive measures of social, communication and motor abilities were obtained at each child's home and repeated at 18, 24, 30 and 36 months of age. The sample included 110 children considered to be at high risk for developing autism because they had older siblings already diagnosed with the same condition.
Preliminary evidence suggests that high-risk 14-month-olds who later develop autism display signs of delayed motor development as early as 6 to 7 months of age, Landa noted. In particular, these youngsters had difficulty keeping their heads stable when slowly raised from a prone position.
A fundamental derailment of postural development may accompany social difficulties typical of children with autism spectrum disorders, remarked psychologist Jana Iverson of the University of Pittsburgh. "The motor system is another place to probe for common underlying features of autism spectrum disorder," Iverson said.
Psychologist Sally Rogers of the University of California, Davis, cautioned that much remains unknown about the early identification and treatment of autism. Infant siblings of older children with autism represent a special group that's especially likely to show early signs of the same disorder, she suggested.
"I'm not sure the majority of children with autism spectrum disorder have predictive symptoms by 12 or 14 months," Rogers said. In her own long-term studies, some children without autistic siblings show a gradual slowing of social and language development over several years that leads to autism, while others show no autism symptoms at all until being diagnosed with the disorder at age 4 or 5.
Posted: 12 Mar 2010 02:09 PM PST
A new study of a 2005 earthquake in Chile supports the surprising hypothesis that pregnant women who experience earthquakes during the first trimester of their pregnancies have increased risk of premature birth and slightly smaller babies.
While the drops in birth weight and gestation time are relatively small, they are big enough to suggest that earthquakes experienced more than six months before birth can negatively impact a pregnancy.
"It's statistically significant, way above the margin of error," said Florencia Torche, the NYU sociologist who crunched the number, which has been submitted to a demographic journal. "It's not due to chance."
Torche's new study has not yet been through peer review, but it is consistent with an emerging line of research on the impacts of earthquakes on mothers and their unborn. Maternal stress has long been linked to premature birth and low birth weights, but it was a landmark 2001 study of the 1994 Northridge earthquake (.pdf) that pointed out that major seismic activity made a measurable impact on the expectant mothers who felt it.
But counter-intuitively, it wasn't the mothers closest to labor who were affected the most, but the women who'd just gotten pregnant. The women who were in their first three months of pregnancy had their babies more than a week earlier than similar women who did not experience the quake.
While the researchers in 2001 (led by University of California, Irvine pregnancy researcher Laura Glynn) admitted that the "precise mechanism through which stress affects length of gestation is not known," they hypothesized that perhaps the earthquake activated some kind of "placental clock." Perhaps a burst of corticotropin-releasing hormone, a known stress response, serves as a signal to the pregnant woman's body that she should have the baby sooner than normal.
Premature birth, and the low birth weight that's associated with it, has been linked to long-term negative consequences.
"Low birth weight is associated with a bunch of poor outcomes throughout your life cycle," Torche said.
Even without a clear-cut mechanism, it may be possible to mitigate some of the negative outcomes of the earthquake stress.
"We can certainly work to try and compensate and provide services for these moms that are affected," Torche said. "For instance, mental health services might be really relevant. Something we don't usually consider. You can think of programs that would do with early childhood development. If these kids are at higher risk, and you provide support stimulation, that can thoroughly compensate for this very early disadvantage."
The monster magnitude 8.8 earthquake in Chile on Feb. 27 may also focus renewed effort on figuring out whether the size of the quake is proportional to the prematurity of the birth. To do that, researchers will need more studies on more earthquakes, Torche said.
Citations: 1) "The Effect of Maternal Stress on Birth Outcomes: Exploiting a Natural Experiment" by Florencia Torche. In review. Available via the author.
2) "When stress happens matters:Effects of earthquake timing on stress responsivity in pregnancy" by Laura M. Glynn, Pathik D. Wadhwa, Christine Dunkel-Schetter, Aleksandra Chicz-DeMet,and Curt A. Sandman. Am J Obstet Gynecol 2001;184:637-42.
Posted: 12 Mar 2010 11:04 AM PST
A small, newly discovered comet will not get a chance to enjoy its fame for long.
As you can see in this image sequence obtained by NASA's Solar and Heliosopheric Observatory, the comet is on a collision course with the sun. Things will not end well for the comet, which will burn.
The comet is believed to be a Kreutz Sungrazer, a class of objects that are fragments of a supercomet that broke up long ago. Many of them are discovered by amateur astronomer internet users (like you) staring at NASA data.
The solar images also show a coronal mass ejection at the upper left of the frame. These expulsions of energetic particles from the sun cause solar storms here on Earth and tend to create beautiful auroral displays in the Earth's polar regions. The other bright object in the video is the planet Mercury.
Posted: 12 Mar 2010 10:24 AM PST
Newly reported observations of gas flows on the solar surface may explain why the sun recently had such an extended case of the doldrums.
From 2008 through the first half of 2009, the sun had a puzzling dearth of sunspots, flares and other storms, extending the usual lull at the end of the 11-year solar activity cycle for an extra 15 months. Findings from the study, which relied on the orbiting Solar and Heliospheric Observatory, or SOHO, may also suggest a better way to forecast the intensity and duration of future solar cycles.
Better predictions could be critical because some solar outbursts can blast Earth with massive, magnetized clouds of charged particles capable of knocking out electrical power grids and harming communications satellites.
In the March 12 Science, David Hathaway of NASA's Marshall Space Flight Center in Huntsville, Ala., and Lisa Rightmire of the University of Memphis in Tennessee analyzed 13 years of SOHO measurements that tracked the movement of ionized gas from the solar equator to the poles. The researchers found that the relatively slow gas movement, known as the meridional flow, sped up a few years before the last solar minimum began in 2008. What's more, the flow was substantially faster than the speed at the previous solar minimum, a more typical and less extended downturn in solar activity some 11 years earlier.
Hathaway and Rightmire suggest that the faster meridional flow produced weaker magnetic fields at the sun's poles, which extended the solar minimum.
Magnetic fields carried by the meridional flow typically oppose much stronger flows of magnetized material on the surface, Hathaway says. The faster the meridional flow is, the greater the opposition is to those other flows. As a result, the sun's polar magnetic field can't become as strong, the researchers propose.
"It is possible that the delayed start of the present cycle, 2009 to 2010, was caused by the relatively weak polar field in 2007 to 2009," comments Neil Sheeley of the Naval Research Laboratory in Washington, D.C.
The strength of the magnetic polar fields plays a critical role in determining the onset of the next solar cycle, Hathaway notes. These fields dive beneath the solar surface, building up the deep sunspot-generating magnetic fields that signal the beginning of the next solar cycle. Weaker polar fields take more time to reach the strength required to produce sunspots, prolonging the lull in activity from the previous cycle. In addition, weaker-than-usual polar fields are likely to produce less activity during the subsequent solar cycle, Hathaway and Rightmire predict.
"The fact that the meridional flow plays a key role in setting up the sun's polar fields for the next cycle suggests that future observations will help us predict [the duration and intensity of] future cycles," Hathaway says.
One caveat is that physicists have only an incomplete understanding of the solar cycle and the transport of magnetic material below the solar surface, Sheeley says.
"This is certainly an interesting result and may help discriminate between different classes of models of solar magnetism," notes Natchimuthuk Gopalswamy of NASA's Goddard Space Flight Center in Greenbelt, Md.
Other models, says Hathaway, which also embrace the importance of the meridional flow but rely on the complicated magnetic dynamics that happen below the surface, come to just the opposite conclusion: A fast meridional flow leads to strong polar field and a shorter solar minimum. Those models may now need to be revised, he says.
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