Massive volcanic eruptions caused Little Ice Age, froze the Thames

The research, which looked at chemical clues preserved in Arctic vegetation as well as other data, also pinpointed the start of the Little Ice Age to the end of the 13th century.

A mysterious, centuries-long cool spell, dubbed the Little Ice Age, appears to have been caused by a series of volcanic eruptions and sustained by sea ice, a new study indicates.

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The research, which looked at chemical clues preserved in Arctic vegetation as well as other data, also pinpointed the start of the Little Ice Age to the end of the 13th century.

During the cool spell, which lasted into the late 19th century, advancing glaciers destroyed northern European towns and froze the Thames River in London and canals in the Netherlands, places that are now ice-free. There is also evidence it affected other continents.

"This is the first time anyone has clearly identified the specific onset of the cold times marking the start of the Little Ice Age," said Gifford Miller, a geological sciences professor at the University of Colorado, Boulder, and the lead study researcher. "We also have provided an understandable climate feedback system that explains how this cold period could be sustained for a long period of time."

The cause appears to have been massive tropical volcanic eruptions, which spewed tiny particles called?aerosols into the atmosphere. While suspended in the air, the aerosols reflect solar radiation back into space, cooling the planet below. ?

The cooling was sustained after the aerosols had left the atmosphere by a sea-ice feedback in the North Atlantic Ocean, the researchers believe. Expanding sea ice would have melted into the North Atlantic Ocean, interfering with the normal mixing between surface and deeper waters. This meant the water flowing back to the Arctic was colder, helping to sustain large areas of sea ice, which, in turn, reflect sunlight back into the atmosphere. The result was a self-sustaining feedback loop.

Miller and colleagues came to these conclusions by looking at radiocarbon dates ? based on how much of the radioactive form of carbon they contain?? from dead plants revealed by melting ice on Baffin Island, in the Canadian Arctic. Their analysis found that many plants at both high and low altitudes died between A.D. 1275 and A.D. 1300 ? evidence that Baffin Island froze over suddenly. Many plants also appeared to have died at around A.D. 1450, an indication of a second major cooling.

These periods coincide with two of the most volcanically active half centuries in the past millennium, according to the researchers. [History's Biggest Volcanic Eruptions]

They also found that the annual layers in sediment cores from a glacial lake linked with an ice cap in Iceland suddenly became thicker, indicating increased erosion caused by the expansion of the ice cap in the late 13th century and in the 15th century?.

"This gave us a great deal more confidence that there was a major perturbation to the Northern Hemisphere climate near the end of the 13th century," Miller said.?

Simulations using a climate model showed that several large, closely spaced eruptions could have cooled the Northern Hemisphere enough to spark sea-ice growth and the subsequent feedback loop.

It's unlikely?decreased solar radiation, a separate theory to explain the Little Ice Age, played a role, according to the researchers.

The research will appear Tuesday (Jan. 31) in the journal Geophysical Research Letters.

You can follow?LiveScience?senior?writer Wynne Parry on Twitter?@Wynne_Parry.?Follow LiveScience for the latest in science news and discoveries on Twitter@livescience?and on?Facebook.

Source: http://rss.csmonitor.com/~r/feeds/csm/~3/mO-fKwv3hPM/Massive-volcanic-eruptions-caused-Little-Ice-Age-froze-the-Thames

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Perfect nanotubes shine brightest

[ Back to EurekAlert! ] Public release date: 31-Jan-2012
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Contact: David Ruth
david@rice.edu
713-348-6327
Rice University

Rice University researchers show how length, imperfections affect carbon nanotube fluorescence

A painstaking study by Rice University has brought a wealth of new information about single-walled carbon nanotubes through analysis of their fluorescence.

The current issue of the American Chemical Society journal ACS Nano features an article about work by the Rice lab of chemist Bruce Weisman to understand how the lengths and imperfections of individual nanotubes affect their fluorescence in this case, the light they emit at near-infrared wavelengths.

The researchers found that the brightest nanotubes of the same length show consistent fluorescence intensity, and the longer the tube, the brighter. "There's a rather well-defined limit to how bright they appear," Weisman said. "And that maximum brightness is proportional to length, which suggests those tubes are not affected by imperfections."

But they found that brightness among nanotubes of the same length varied widely, likely due to damaged or defective structures or chemical reactions that allowed atoms to latch onto the surface.

The study first reported late last year by Weisman, lead author/former graduate student Tonya Leeuw Cherukuri and postdoctoral fellow Dmitri Tsyboulski detailed the method by which Cherukuri analyzed the characteristics of 400 individual nanotubes of a specific physical structure known as (10,2).

"It's a tribute to Tonya's dedication and talent that she was able to make this large number of accurate measurements," Weisman said of his former student.

The researchers applied spectral filtering to selectively view the specific type of nanotube. "We used spectroscopy to take this very polydisperse sample containing many different structures and study just one of them, the (10,2) nanotubes," Weisman said. "But even within that one type, there's a wide range of lengths."

Weisman said the study involved singling out one or two isolated nanotubes at a time in a dilute sample and finding their lengths by analyzing videos of the moving tubes captured with a special fluorescence microscope. The movies also allowed Cherukuri to catalog their maximum brightness.

"I think of these tubes as fluorescence underachievers," he said. "There are a few bright ones that fluoresce to their full potential, but most of them are just slackers, and they're half as bright, or 20 percent as bright, as they should be.

"What we want to do is change that distribution and leave no tube behind, try to get them all to the top. We want to know how their fluorescence is affected by growth methods and processing, to see if we're inflicting damage that's causing the dimming.

"These are insights you really can't get from measurements on bulk samples," he said.

Graduate student Jason Streit is extending Cherukuri's research. "He's worked up a way to automate the experiments so we can image and analyze dozens of nanotubes at once, rather than one or two. That will let us do in a couple of weeks what had taken months with the original method," Weisman said.

###

The research was supported by the Welch Foundation, the National Science Foundation and Applied NanoFluorescence.

Read the ACS Nano article "How Nanotubes Get Their Glow" here: http://pubs.acs.org/doi/full/10.1021/nn2050328

Read the abstract here: http://pubs.acs.org/doi/abs/10.1021/nn2043516

See a video of fluorescent carbon nanotubes here: http://youtu.be/4ceWLcOMxz0

CAPTION:

A video produced by the Rice University lab of chemist Bruce Weisman shows a selection of nanotubes fluorescing as they twist and turn in a solution. New work at Rice revealed how the fluorescent properties of specific types of nanotubes are influenced by the length of the tube and any imperfections. Weisman said those properties may be important to medical imaging and industrial applications. (Credit: Jason Streit/Rice University)

Located on a 300-acre forested campus in Houston, Rice University is consistently ranked among the nation's top 20 universities by U.S. News & World Report. Rice has highly respected schools of Architecture, Business, Continuing Studies, Engineering, Humanities, Music, Natural Sciences and Social Sciences and is known for its "unconventional wisdom." With 3,708 undergraduates and 2,374 graduate students, Rice's undergraduate student-to-faculty ratio is less than 6-to-1. Its residential college system builds close-knit communities and lifelong friendships, just one reason why Rice has been ranked No. 1 for best quality of life multiple times by the Princeton Review and No. 4 for "best value" among private universities by Kiplinger's Personal Finance. To read "What they're saying about Rice," go to http://www.rice.edu/nationalmedia/Rice.pdf.



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?


AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert! system.


[ Back to EurekAlert! ] Public release date: 31-Jan-2012
[ | E-mail | Share Share ]

Contact: David Ruth
david@rice.edu
713-348-6327
Rice University

Rice University researchers show how length, imperfections affect carbon nanotube fluorescence

A painstaking study by Rice University has brought a wealth of new information about single-walled carbon nanotubes through analysis of their fluorescence.

The current issue of the American Chemical Society journal ACS Nano features an article about work by the Rice lab of chemist Bruce Weisman to understand how the lengths and imperfections of individual nanotubes affect their fluorescence in this case, the light they emit at near-infrared wavelengths.

The researchers found that the brightest nanotubes of the same length show consistent fluorescence intensity, and the longer the tube, the brighter. "There's a rather well-defined limit to how bright they appear," Weisman said. "And that maximum brightness is proportional to length, which suggests those tubes are not affected by imperfections."

But they found that brightness among nanotubes of the same length varied widely, likely due to damaged or defective structures or chemical reactions that allowed atoms to latch onto the surface.

The study first reported late last year by Weisman, lead author/former graduate student Tonya Leeuw Cherukuri and postdoctoral fellow Dmitri Tsyboulski detailed the method by which Cherukuri analyzed the characteristics of 400 individual nanotubes of a specific physical structure known as (10,2).

"It's a tribute to Tonya's dedication and talent that she was able to make this large number of accurate measurements," Weisman said of his former student.

The researchers applied spectral filtering to selectively view the specific type of nanotube. "We used spectroscopy to take this very polydisperse sample containing many different structures and study just one of them, the (10,2) nanotubes," Weisman said. "But even within that one type, there's a wide range of lengths."

Weisman said the study involved singling out one or two isolated nanotubes at a time in a dilute sample and finding their lengths by analyzing videos of the moving tubes captured with a special fluorescence microscope. The movies also allowed Cherukuri to catalog their maximum brightness.

"I think of these tubes as fluorescence underachievers," he said. "There are a few bright ones that fluoresce to their full potential, but most of them are just slackers, and they're half as bright, or 20 percent as bright, as they should be.

"What we want to do is change that distribution and leave no tube behind, try to get them all to the top. We want to know how their fluorescence is affected by growth methods and processing, to see if we're inflicting damage that's causing the dimming.

"These are insights you really can't get from measurements on bulk samples," he said.

Graduate student Jason Streit is extending Cherukuri's research. "He's worked up a way to automate the experiments so we can image and analyze dozens of nanotubes at once, rather than one or two. That will let us do in a couple of weeks what had taken months with the original method," Weisman said.

###

The research was supported by the Welch Foundation, the National Science Foundation and Applied NanoFluorescence.

Read the ACS Nano article "How Nanotubes Get Their Glow" here: http://pubs.acs.org/doi/full/10.1021/nn2050328

Read the abstract here: http://pubs.acs.org/doi/abs/10.1021/nn2043516

See a video of fluorescent carbon nanotubes here: http://youtu.be/4ceWLcOMxz0

CAPTION:

A video produced by the Rice University lab of chemist Bruce Weisman shows a selection of nanotubes fluorescing as they twist and turn in a solution. New work at Rice revealed how the fluorescent properties of specific types of nanotubes are influenced by the length of the tube and any imperfections. Weisman said those properties may be important to medical imaging and industrial applications. (Credit: Jason Streit/Rice University)

Located on a 300-acre forested campus in Houston, Rice University is consistently ranked among the nation's top 20 universities by U.S. News & World Report. Rice has highly respected schools of Architecture, Business, Continuing Studies, Engineering, Humanities, Music, Natural Sciences and Social Sciences and is known for its "unconventional wisdom." With 3,708 undergraduates and 2,374 graduate students, Rice's undergraduate student-to-faculty ratio is less than 6-to-1. Its residential college system builds close-knit communities and lifelong friendships, just one reason why Rice has been ranked No. 1 for best quality of life multiple times by the Princeton Review and No. 4 for "best value" among private universities by Kiplinger's Personal Finance. To read "What they're saying about Rice," go to http://www.rice.edu/nationalmedia/Rice.pdf.



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?


AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert! system.


Source: http://www.eurekalert.org/pub_releases/2012-01/ru-pns013112.php

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Breathtaking Cloud Formation Shines Over Rockies (LiveScience.com)

This spectacular, multi-hued formation of lenticular clouds was observed soon after the sun set over Rocky Mountain National Park near Estes Park, Colo., on Jan. 5.?

Professional photographer Richard H. Hahn was on the south side of the park's Deer Mountain when he noticed the unique cloud formation in the dusk sky. He rushed to find a shooting angle that would place the colorful clouds in the context of the valley and mountains, and he snapped the magnificent view at 5:02 p.m. MST (7:02 EST).

"The great colors lasted only a few minutes, so it was a lucky observation," Hahn told OurAmazingPlanet. "I felt very grateful to be in a high-enough elevation with a favorable shooting angle to capture this scene with perspective."

Lenticular clouds are characterized by their smooth, symmetrical oval or round shapes, and because of this, they are often referred to as "flying saucer" or "UFO" clouds. They can appear near the lee side of a mountain ridge, which is the portion of the mountain sheltered from winds.

"I have seen quite a few interesting lenticulars during my nine years in Colorado, but never one quite like this," Hahn said. "The significance of this particular atmospheric event was the dramatic shape and color of the cloud. It really did look like the mothership UFO." ?

Lenticular clouds form when waves of moist, fast-moving air are pushed upward by winds and ascend over high mountains. At the mountain's higher altitude, the moist air's water droplets cool and expand, and the water vapor condenses. When the air moves over the mountaintop and descends to uniformly humid conditions, lenticular clouds form.

They can look like one large, lens-shaped cloud, or several waves of moist air can result in lenticular clouds that resemble pancakes stacked atop each other, like the ones in this photo.

Because the photo was taken about 20 minutes after sunset, Hahn explained that the cloud's beautiful pink, orange and melon colors required a clear sky between the lenticular cloud and the western horizon. The setting sun's rays were able to reach the high-hanging cloud.

"The air was dead quiet at my location, which is a big contrast to the high-velocity winds implied by the lenticular cloud at higher altitudes," Hahn added.?"It was ominous and breathtaking."

This story was provided by OurAmazingPlanet, a sister site to LiveScience. You can follow LiveScience writer Remy Melina on Twitter @remymelina. Follow LiveScience for the latest in science news and discoveries on Twitter @livescience? and on Facebook.

Source: http://us.rd.yahoo.com/dailynews/rss/science/*http%3A//news.yahoo.com/s/livescience/20120131/sc_livescience/breathtakingcloudformationshinesoverrockies

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One-Night Stand or Rape?

A: Being obnoxious is almost a job description for a 15-year-old, and you can't control what she says with friends. But it's your parents? job?and I hope they step up and discharge it?to explain to her that she is never, ever to make a disparaging remark to your brother's girlfriend, or to anyone, anytime, about their physical qualities, disabilities, race, accent, etc. So tell your parents about your concerns and ask them to speak to your sister so that she doesn't embarrass your family. And if you hear her making mocking remarks, keep it simple and say, "Mia, those kinds of comments just aren't acceptable."

Source: http://feeds.slate.com/click.phdo?i=3b0b86b6b562e28321117ebcba66bb2e

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Paying To Serve: Microsoft Offers Accelerator-Backed Startups $60,000* In Azure Cloud Usage

Screen Shot 2012-01-30 at 12.43.26 PMThe perks of getting into a top startup accelerator just got a little better. Microsoft is now offering startups in its new BizSpark Plus program?$60,000 worth of costs for using its Azure cloud computing program. This includes any company that's a part of TechStars?or?its affiliated Global Accelerator Network, as well as Seedcamp, Dogpatch Labs, and a list of others. Let's say your hot new startup has just launched to the public, gotten TechCrunched, and is dealing with its big first wave of traffic. This deal will let you quickly scale up to meet the demand without blowing your seed funding on emergency virtual machines. An open cloud services platform, Azure works with major development languages including node.js, java, php and Microsoft's own . net, among others -- the point, from Microsoft's perspective, is to get in with the next batch of companies before they get hooked on offerings from rivals like Amazon.

Source: http://feedproxy.google.com/~r/Techcrunch/~3/lQGCxRXUvpE/

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Missing toddler's blood found at dad's home

By msnbc.com staff and news services

WATERVILLE, Maine -- Some of the blood found in a Maine home where a missing toddler was last seen six weeks ago belonged to the little girl, an official said Sunday.

State Police spokesman Steve McCausland would not say how much of Ayla Reynolds' blood was found in her father's home in Waterville, where exactly it was found or how long it might have been there.

"Our first priority is finding Ayla,? McCausland told the Bangor Daily News.


But investigators told Ayla's mother's family that the amount of blood was "more blood than a small cut would produce," according to a family-run website.

"Even in light of this evidence we are more determined than ever to find out what has happened to Ayla and we still cling to the hope that she is alive and will be returned to us," the website said. "We urge anyone that has information about Ayla to come forward now and unburden yourself of the truth."

Broken arm
Ayla's father, Justin DiPietro, reported her missing Dec. 17. He had put her to bed the night before and said she wasn't there the next morning. DiPietro told police she was wearing green pajamas with polka dots and the words "Daddy's Princess" on them and had a soft cast on her broken left arm.

DiPietro could not immediately be reached for comment Sunday; his cellphone voicemail was full and unable to accept messages.

After hours of intense questioning, the mother of missing toddler Ayla Reynolds says she had to stop participating in a lie-detector test due to a medical condition. NBC's Aditi Roy reports.

Ayla was 20 months old when she disappeared. She had been staying with her father at the time in the house where DiPietro lives with his mother. Her mother, Trista Reynolds, lives in Portland.

The blood was among hundreds of pieces of potential evidence that were removed from the Waterville home as part of a criminal investigation into the girl's disappearance.

Trista Reynolds and DiPietro were photographed together at a vigil for Ayla on Saturday.

WCVB quoted Trista Reynolds as saying she was "ready to go knocking at people's doors myself because I want to know what happened to my daughter. "

'It was a surprise'
Trista Reynolds' father said the family was told late Saturday by McCausland that blood found in the home was determined to be Ayla's.

"It was a surprise," Ronald Reynolds said.

He said police did not give any indication what the discovery means.

Ronald Reynolds said he is convinced the family in DiPietro's house has more information than they have shared.

Trista Reynolds, the mom of missing Maine toddler Ayla, tells TODAY's Matt Lauer she's still suspicious of the baby's father for his sudden interest in the case.

"Every day, it gets hotter and hotter," he said. "I hope they pull them back in, set them down and give them the opportunity to say something."

DiPietro, his mother and a third adult were home the night of Dec. 16, and police have questioned all three, McCausland said Saturday.

"We believe they have not given us the full story," he said.

DiPietro has said he took a polygraph test, but has declined to say what the results were.

The Associated Press and msnbc.com staff contributed to this report.

Source: http://usnews.msnbc.msn.com/_news/2012/01/30/10267899-missing-toddler-ayla-reynolds-blood-found-at-dads-home-in-waterville-maine

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Lumbar disc degeneration more likely in overweight and obese adults

[ Back to EurekAlert! ] Public release date: 30-Jan-2012
[ | E-mail | Share Share ]

Contact: Dawn Peters
healthnews@wiley.com
781-388-8408
Wiley-Blackwell

Elevated BMI linked to greater extent and severity of degenerative disc disease

One of the largest studies to investigate lumbar spine disc degeneration found that adults who are overweight or obese were significantly more likely to have disc degeneration than those with a normal body mass index (BMI). Assessments using magnetic resonance imaging (MRI) show elevated BMI is associated with an increased number of levels of degenerated disks and greater severity of disc degeneration, including narrowing of the disc space. Details of this study now appear in Arthritis & Rheumatism, a journal published by Wiley-Blackwell on behalf of the American College of Rheumatology (ACR).

The World Health Organization (WHO) reports that obesityone of the most preventable risk factors for a number of diseaseshas more than doubled since 1980. According to WHO, in 2008 roughly 1.5 billion people aged 20 and older were overweight, with more than 200 million men and close to 300 million women considered obese. In the U.S., studies estimate one in three children is overweight or obese and excess weight could lead to more severe obesity in adulthood.

Moreover, previous research has linked higher BMI to low back pain, which is often debilitating and can limit function, impact psychological well being, diminish overall quality of life, and is associated with substantial socioeconomic and health-care costs. Experts suggest that disc degeneration is one cause of low back pain, and therefore, BMI could be involved in the development of degenerative disc disease. To expand the knowledge of this important health concern, a team of researchers led by Drs. Dino Samartzis and Kenneth M.C. Cheung at the University of Hong Kong in Hong Kong investigated the association between elevated BMI and presence, extent, and severity of lumbar spine disc degeneration on MRI in adults.

The team recruited 2,599 participants aged 21 and older from Southern China between 2001 and 2009. Participants were from diverse social and economic backgrounds and were recruited regardless of whether they had lower back pain or not. The study group included 1,040 men and 1,559 women who had a mean age of 42 years. Researchers conducted radiographic and clinical assessments, and MRIs of the lumbar spine were obtained for all subjects.

Study findings reveal that 73% of participants displayed disc degeneration, with men (76%) having a significantly higher prevalence of degeneration than women (71%). Not surprisingly, increasing age was found to increase the prevalence of disc degeneration. BMI assessments of the study group show that 7% of subjects were underweight, 48% were in the normal weight range, 36% were overweight, and 9% were obese.

"Our research confirms that with elevated BMI there is a significant increase in the extent and global severity of disc degeneration. In fact, end-stage disc degeneration with narrowing of the disc space was more pronounced in obese individuals," said Dr. Samartzis. The authors suggest that with weight gain, physical loading on the disc and/or a chronic low-grade inflammation from the fat cells may play a role in disc degeneration. Dr. Samartzis further added that "Since overweight and obesity are worldwide concerns whose prevalence continues to rise, our study's findings have considerable public health implications. If these issues continue to plague society, they can further affect spine health leading to low back pain and its consequences."

The authors note that disc degeneration is a complex process involving structural and chemical changes of the disc. They recommend that future studies that investigate risk factors for disc degeneration should take into account the impact of overweight and obesity on the disease. Dr. Cheung concludes, "Deeper understanding of how elevated BMI contributes to disc degeneration and low back pain could aid in the development of novel interventions that can improve quality of life for those with these disabling conditions."

###

This study is published in Arthritis & Rheumatism. Media wishing to receive a PDF of this article may contact healthnews@wiley.com

Full citation: "The Association of Lumbar Intervertebral Disc Degeneration on MRI in Overweight and Obese Adults: A Population-Based Study." Dino Samartzis, Jaro Karppinen, Danny Chan, Keith D.K. Luk and Kenneth M.C. Cheung. Arthritis & Rheumatism; Published Online: January 30, 2012 (DOI: 10.1002/art.33462).

URL Upon publication: http://doi.wiley.com/10.1002/art.33462.

Author Contact: Dr. Samartzis can be reached at dsamartzis@msn.com or +852 9584-2395.

About the Journal:

Arthritis & Rheumatism is an official journal of the American College of Rheumatology (ACR) and the Association of Rheumatology Health Professionals (ARHP), a division of the College, and covers all aspects of inflammatory disease. The American College of Rheumatology (www.rheumatology.org) is the professional organization who share a dedication to healing, preventing disability, and curing the more than 100 types of arthritis and related disabling and sometimes fatal disorders of the joints, muscles, and bones. Members include practicing physicians, research scientists, nurses, physical and occupational therapists, psychologists, and social workers. The journal is published by Wiley-Blackwell on behalf of the ACR. For more information, please visit http://onlinelibrary.wiley.com/journal/10.1002/(ISSN)1529-0131.

About Wiley-Blackwell:

Wiley-Blackwell is the international scientific, technical, medical, and scholarly publishing business of John Wiley & Sons, with strengths in every major academic and professional field and partnerships with many of the world's leading societies. Wiley-Blackwell publishes nearly 1,500 peer-reviewed journals and 1,500+ new books annually in print and online, as well as databases, major reference works and laboratory protocols. For more information, please visit www.wileyblackwell.com or our new online platform, Wiley Online Library (wileyonlinelibrary.com), one of the world's most extensive multidisciplinary collections of online resources, covering life, health, social and physical sciences, and humanities.


[ Back to EurekAlert! ] [ | E-mail | Share Share ]

?


AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert! system.


[ Back to EurekAlert! ] Public release date: 30-Jan-2012
[ | E-mail | Share Share ]

Contact: Dawn Peters
healthnews@wiley.com
781-388-8408
Wiley-Blackwell

Elevated BMI linked to greater extent and severity of degenerative disc disease

One of the largest studies to investigate lumbar spine disc degeneration found that adults who are overweight or obese were significantly more likely to have disc degeneration than those with a normal body mass index (BMI). Assessments using magnetic resonance imaging (MRI) show elevated BMI is associated with an increased number of levels of degenerated disks and greater severity of disc degeneration, including narrowing of the disc space. Details of this study now appear in Arthritis & Rheumatism, a journal published by Wiley-Blackwell on behalf of the American College of Rheumatology (ACR).

The World Health Organization (WHO) reports that obesityone of the most preventable risk factors for a number of diseaseshas more than doubled since 1980. According to WHO, in 2008 roughly 1.5 billion people aged 20 and older were overweight, with more than 200 million men and close to 300 million women considered obese. In the U.S., studies estimate one in three children is overweight or obese and excess weight could lead to more severe obesity in adulthood.

Moreover, previous research has linked higher BMI to low back pain, which is often debilitating and can limit function, impact psychological well being, diminish overall quality of life, and is associated with substantial socioeconomic and health-care costs. Experts suggest that disc degeneration is one cause of low back pain, and therefore, BMI could be involved in the development of degenerative disc disease. To expand the knowledge of this important health concern, a team of researchers led by Drs. Dino Samartzis and Kenneth M.C. Cheung at the University of Hong Kong in Hong Kong investigated the association between elevated BMI and presence, extent, and severity of lumbar spine disc degeneration on MRI in adults.

The team recruited 2,599 participants aged 21 and older from Southern China between 2001 and 2009. Participants were from diverse social and economic backgrounds and were recruited regardless of whether they had lower back pain or not. The study group included 1,040 men and 1,559 women who had a mean age of 42 years. Researchers conducted radiographic and clinical assessments, and MRIs of the lumbar spine were obtained for all subjects.

Study findings reveal that 73% of participants displayed disc degeneration, with men (76%) having a significantly higher prevalence of degeneration than women (71%). Not surprisingly, increasing age was found to increase the prevalence of disc degeneration. BMI assessments of the study group show that 7% of subjects were underweight, 48% were in the normal weight range, 36% were overweight, and 9% were obese.

"Our research confirms that with elevated BMI there is a significant increase in the extent and global severity of disc degeneration. In fact, end-stage disc degeneration with narrowing of the disc space was more pronounced in obese individuals," said Dr. Samartzis. The authors suggest that with weight gain, physical loading on the disc and/or a chronic low-grade inflammation from the fat cells may play a role in disc degeneration. Dr. Samartzis further added that "Since overweight and obesity are worldwide concerns whose prevalence continues to rise, our study's findings have considerable public health implications. If these issues continue to plague society, they can further affect spine health leading to low back pain and its consequences."

The authors note that disc degeneration is a complex process involving structural and chemical changes of the disc. They recommend that future studies that investigate risk factors for disc degeneration should take into account the impact of overweight and obesity on the disease. Dr. Cheung concludes, "Deeper understanding of how elevated BMI contributes to disc degeneration and low back pain could aid in the development of novel interventions that can improve quality of life for those with these disabling conditions."

###

This study is published in Arthritis & Rheumatism. Media wishing to receive a PDF of this article may contact healthnews@wiley.com

Full citation: "The Association of Lumbar Intervertebral Disc Degeneration on MRI in Overweight and Obese Adults: A Population-Based Study." Dino Samartzis, Jaro Karppinen, Danny Chan, Keith D.K. Luk and Kenneth M.C. Cheung. Arthritis & Rheumatism; Published Online: January 30, 2012 (DOI: 10.1002/art.33462).

URL Upon publication: http://doi.wiley.com/10.1002/art.33462.

Author Contact: Dr. Samartzis can be reached at dsamartzis@msn.com or +852 9584-2395.

About the Journal:

Arthritis & Rheumatism is an official journal of the American College of Rheumatology (ACR) and the Association of Rheumatology Health Professionals (ARHP), a division of the College, and covers all aspects of inflammatory disease. The American College of Rheumatology (www.rheumatology.org) is the professional organization who share a dedication to healing, preventing disability, and curing the more than 100 types of arthritis and related disabling and sometimes fatal disorders of the joints, muscles, and bones. Members include practicing physicians, research scientists, nurses, physical and occupational therapists, psychologists, and social workers. The journal is published by Wiley-Blackwell on behalf of the ACR. For more information, please visit http://onlinelibrary.wiley.com/journal/10.1002/(ISSN)1529-0131.

About Wiley-Blackwell:

Wiley-Blackwell is the international scientific, technical, medical, and scholarly publishing business of John Wiley & Sons, with strengths in every major academic and professional field and partnerships with many of the world's leading societies. Wiley-Blackwell publishes nearly 1,500 peer-reviewed journals and 1,500+ new books annually in print and online, as well as databases, major reference works and laboratory protocols. For more information, please visit www.wileyblackwell.com or our new online platform, Wiley Online Library (wileyonlinelibrary.com), one of the world's most extensive multidisciplinary collections of online resources, covering life, health, social and physical sciences, and humanities.


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Source: http://www.eurekalert.org/pub_releases/2012-01/w-ldd012512.php

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Jumping Spiders see clearly by blurring their vision

Researchers in Japan have now discovered that the arachnids accurately sense distances by comparing a blurry version of an image with a clear one, a method called image defocus.

Jumping spiders, which hunt by pouncing on their prey, gauge distances to their unsuspecting meals in a way that appears to be unique in the animal kingdom, a new study finds.

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The superability boils down to seeing green, the researchers found.

There are several different visual systems that organisms use to accurately and reliably judge distance and depth. Humans, for example, have binocular stereovision. Because?our eyes?are spaced apart, they receive visual information from different angles, which our brains use to automatically triangulate distances. Other animals, such as insects, adjust the focal length of the lenses in their eyes, or move their heads side to side to create an effect called motion parallax ? nearer objects will move across their field of vision more quickly than objects farther away.

However,?jumping spiders?(Hasarius adansoni) lack any kind of focal adjustment system, have eyes that are too close together for binocular stereovision and don?t appear to use motion parallax while hunting. So how are these creatures able to perceive depth?

Researchers in Japan have now discovered that the arachnids accurately sense distances by comparing a blurry version of an image with a clear one, a method called image defocus.

Jumping spiders have four eyes densely packed in a row: two large principal eyes and two small lateral eyes. The spider uses its lateral eyes to sense the motion of an object, such as a fly, which it then zeros in on using its principal eyes, Akihisa Terakita, a biologist at Osaka City University in Japan and lead author of the new study, explained in an email to LiveScience.

Rather than having a single layer of?photoreceptor cells, the retinas in the spider?s principal eyes have four distinct photoreceptor layers. When Terakita and his colleagues took a close look at the spider's principal eyes, they found that the two layers closest to the surface contain ultraviolet-sensitive pigments, whereas the deeper layers contain green-sensitive pigments.

However, because of the layers' respective distances from the lens of the eye, incoming green light is only focused on the deepest layer, while the other green-sensitive retinal layer receives defocused or fuzzy images. The researchers hypothesized that the spiders gauge depth cues from the amount of defocus in this fuzzy layer, which is proportional to the distance an object is to the lens of the eye.

To test this, they placed a spider and three to six?fruit flies?in a cylindrical plastic chamber, housed in a white styrene foam box. They then bathed the bugs in different colored lights: If the defocus of green light is important to the spiders, then they should not be able to accurately judge jumping distance in the absence of green light.

Sure enough, the spiders could easily catch the flies under green light, but consistently underestimated their jumps under red light (which doesn't contain shorter-wavelength light, such as green and blue). The researchers suggest that green light is just right to produce the image defocus necessary to gauge distances, unlike other wavelengths of light.

The team doesn?t know if any other animals employ similar depth-perception techniques, though they think the findings could have important implications for the future design of?visual systems in robots.

"Further investigation of the optics, retinal structure and neural basis of depth perception in jumping spiders may provide biological inspiration for computer vision as well," they write in their study, published in the Jan. 27 issue of the journal Science.

Source: http://rss.csmonitor.com/~r/feeds/science/~3/aC8TqWrXnqg/Jumping-Spiders-see-clearly-by-blurring-their-vision

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Etta James remembered as triumphant trailblazer

Stevie Wonder performs at the funeral of singer Etta James, Saturday, Jan. 28, 2012, at Greater Bethany Community Church City of Refuge in Gardena, Calif. James died last Friday at age 73 after battling leukemia and other ailments, including dementia. She was most famous for her classic "At Last," but over her decades-long career, she became revered for her passionate singing voice. (AP Photo/Ringo H.W. Chiu)

Stevie Wonder performs at the funeral of singer Etta James, Saturday, Jan. 28, 2012, at Greater Bethany Community Church City of Refuge in Gardena, Calif. James died last Friday at age 73 after battling leukemia and other ailments, including dementia. She was most famous for her classic "At Last," but over her decades-long career, she became revered for her passionate singing voice. (AP Photo/Ringo H.W. Chiu)

Stevie Wonder performs at the funeral of singer Etta James, Saturday, Jan. 28, 2012, at Greater Bethany Community Church City of Refuge in Gardena, Calif. James died last Friday at age 73 after battling leukemia and other ailments, including dementia. She was most famous for her classic "At Last," but over her decades-long career, she became revered for her passionate singing voice. (AP Photo/Ringo H.W. Chiu)

Donto James, son singer Etta James speaks at his mother's funeral, Saturday, Jan. 28, 2012, at Greater Bethany Community Church City of Refuge in Gardena, Calif. James died last Friday at age 73 after battling leukemia and other ailments, including dementia. She was most famous for her classic "At Last," but over her decades-long career, she became revered for her passionate singing voice. (AP Photo/Ringo H.W. Chiu)

Christina Aguilera performs at the funeral of singer Etta James, Saturday, Jan. 28, 2012, at Greater Bethany Community Church City of Refuge in Gardena, Calif. James died last Friday at age 73 after battling leukemia and other ailments, including dementia. She was most famous for her classic "At Last," but over her decades-long career, she became revered for her passionate singing voice. (AP Photo/Ringo H.W. Chiu)

Christina Aguilera performs at the funeral of singer Etta James, Saturday, Jan. 28, 2012, at Greater Bethany Community Church City of Refuge in Gardena, Calif. James died last Friday at age 73 after battling leukemia and other ailments, including dementia. She was most famous for her classic "At Last," but over her decades-long career, she became revered for her passionate singing voice. (AP Photo/Ringo H.W. Chiu)

GARDENA, California (AP) ? Rhythm & blues legend Etta James was remembered at a service Saturday attended by hundreds of friends, family and fans as a woman who triumphed against all odds to break down cultural and musical barriers in a style that was unfailingly honest.

The Rev. Al Sharpton, a civil rights activist, eulogized James in a rousing speech, describing her remarkable rise from poverty and pain to become a woman whose music became an enduring anthem for weddings and commercials.

Perhaps most famously, President Barack Obama and the first lady shared their first inaugural ball dance to a version of the song sung by Beyonce, who portrayed James in the film "Cadillac Records." Sharpton on Saturday opened his remarks by reading a statement from the president.

"Etta will be remembered for her legendary voice and her contributions to our nation's musical heritage," Obama's statement read.

The Grammy-winning singer died Jan. 20 after battling leukemia and other ailments, including dementia. She had retreated from public life in recent years, but on Saturday her legacy was on display as mourners of all ages and races converged on the City of Refuge church in Gardena, south of downtown Los Angeles.

Among the stars performing tributes to James were Stevie Wonder and Christina Aguilera, who told the gathering that she has included "At Last" in every concert she's performed as a tribute to her musical inspiration.

Wonder performed three songs, including "Shelter In the Rain" and a harmonica solo. James' rose-draped casket was on display, surrounded by wreaths and floral arrangements and pictures of the singer.

Sharpton, who met James when he was an up-and-coming preacher, credited her with helping break down racial barriers through her music.

"She was able to get us on the same rhythms and humming the same ballads and understanding each other's melodies way before we could even use the same hotels," Sharpton said, referring to the era when racial segregation was the law in many U.S. states.

He said James' fame and influence would have been unthinkable to a woman with James' background ? growing up in a broken home during segregation and at times battling her own demons.

"The genius of Etta James is she flipped the script," Sharpton said, alluding to her struggles with addiction, which she eventually overcame.

"She waited until she turned her pain into power," he said, adding that it turned her story away from being a tragic one into one of triumph.

"You beat 'em Etta," Sharpton said in concluding his eulogy. "At last. At last. At last!"

The assembly roared to their feet, and would again stand to applaud performances by Wonder and Aguilera, who filled the sanctuary with their voices.

"Out of all the singers that I've ever heard, she was the one that cut right to my soul and spoke to me," Aguilera said before her performance.

Throughout the service, a portrait of James as a woman who beat the odds in pursuit of her dreams repeatedly emerged.

"Etta is special to me and for me, because she represents the life, the triumphs, the tribulations of a lot of black women all over this world," said U.S. Rep Maxine Waters, a California Democrat.

"It does not matter who sang 'At Last' before or after Etta. It does not matter when it was sung, or where it was sung. 'At Last' was branded by Etta, the raunchy diva ? that's her signature and we will always remember her."

James won four Grammy Awards, including a lifetime achievement honor, and was inducted into the Rock and Roll Hall of Fame in 1993. In her decades-long career, she became revered for her passionate, soulful singing voice.

She scored her first hit when she was just a teenager with the suggestive "Roll With Me, Henry," which had to be changed to "The Wallflower" in order to get airplay. Her 1967 album, "Tell Mama," became one of the most highly regarded soul albums of all time, a mix of rock and gospel music.

She rebounded from a heroin addiction to see her career surge after performing the national anthem at the 1984 Olympics in Los Angeles. She won her first Grammy Award a decade later, and two more in 2003 and 2004.

James is survived by her husband of 42 years, Artis Mills, and two sons, Donto and Sametto James.

"Mom, I love you," Donto James said during brief remarks. "When I get to the gates, can you please be there for me?"

___

Follow Anthony McCartney at http://twitter.com/mccartneyAP

Associated Press

Source: http://hosted2.ap.org/APDEFAULT/386c25518f464186bf7a2ac026580ce7/Article_2012-01-28-Etta%20James-Funeral/id-1d902050374c4cecb43a8f6b2fda27db

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