Decision About One Second Is Postponed for Three Years

News of science:The leap second survives — for at least three more years.
Delegates at an international telecommunications meeting in Geneva were to decide on Thursday whether to recommend the elimination of leap seconds, which are occasionally added to the world’s atomic clocks to keep them synchronized with Earth’s rotational cycles.
Richard C. Beaird, a State Department official who led the American delegation, said in a statement that discussions at the meeting “revealed a heightened degree of interest that has not previously existed on this issue.” With no consensus among the delegates, officials at the International Telecommunication Union, part of the United Nations, sent the issue back to a panel of experts for further study. A revised proposal will be introduced no earlier than 2015.
Mr. Beaird characterized the delay as “a significant step forward” and said the burst of interest in leap seconds “should allow for a decision that will have the widest possible backing.”
Opponents of leap seconds, led by the United States, say the sporadic addition of these timekeeping hiccups is a potential nightmare for computer networks that depend on precise time to coordinate communications.
But nations like Britain that wish to keep the current system say that eliminating leap seconds might create bigger problems.
They also oppose the uncoupling of time from the notion that the length of a day is tied to the motion of Earth and Sun. Because Earth’s rotation is gradually slowing, days are lengthening. Without leap seconds, noon on the clock would slide earlier and earlier in the morning.
The postponement pleased P. Kenneth Seidelmann, a University of Virginia professor who has argued in favor of leap seconds, but he said the study panel had been working on the issue for the better part of 10 years without reaching consensus. “What are they going to accomplish in the next three?” he asked.
The last leap second occurred in 2008. The next one will be added to clocks this year at the end of June.
News source:nytimes

California's tiniest baby goes home from hospital

News of science:

Melinda Guido, the smallest baby ever born in California, will be heading home from the hospital Friday.
She was born four months premature on Aug. 30 and weighed just more than 9 ounces, making her the second smallest in the United States and one of the world's smallest surviving babies.
Melinda was so tiny she could fit into the palm of her doctor's hand.
Doctors say the baby now weighs 4.5 pounds and has progressed enough to be discharged.
The decision was made to deliver Melinda by caesarian section when a problem developed with the placenta, which gives the fetus nutrition, blood and oxygen.
When a baby is that small, doctors say it is anybody's guess what will happen. There is little research about long-term survival. Doctors across the nation often let babies weighing less than 400 grams die. Melinda was just 270 grams at birth –- the size of a soda can.
She spent the first months of her life inside an incubator in the neonatal intensive care unit. A machine helped her breathe, and she got her nutrition through a feeding tube.
The hospital staff says it will keep a close eye on Melinda for the next six years. Children born extremely premature can suffer developmental delays and other problems, including blindness or deafness, according to doctors.
News source:latimesblogs.latimes

National Alzheimer's Plan, USA - HHS Sets 2025 Deadline

News of science:US Health Authorities have set 2025 as the deadline for coming up with an effective Alzheimer's disease treatment. Some would say this is over-ambitious, because there is no current cure for the disease; and none in the pipeline either. The Alzheimer's Association informs that during the second meeting of the Advisory Council on Alzheimer's Research, Care and Services, ". . . in-depth discussions took place about goals and strategies to change the trajectory of Alzheimer's disease."

Harry Johns, president and CEO of the Alzheimer's Association and member of the Advisory Council, said:

"Alzheimer's can't wait and families won't forget. For the first time ever, families grappling with this progressive, degenerative and ultimately fatal disease can have real hope that a national strategy addressing the escalating Alzheimer's crisis is coming."

The Alzheimer's Association says that approximately 5.4 million people in the USA live with Alzheimer's, while a further 15 million family members and friends provide round-the-clock care. This year, the Alzheimer's disease economic toll will reach about $183 billion in the USA, and is expected to exceed $1 trillion by the middle of this century.

Of the ten leading causes of death today, Alzheimer's is the only one with no treatment to prevent or cure it, or even slow down its progression.

According to Alzheimer's Disease International, there are about 37 million people globally living with Alzheimer's - numbers are expected to rise to 66 million in 2030 and 115 million in 2050.

The national Alzheimer's plan is a result of the new law signed in by President Obama - The National Alzheimer's Project Act (NAPA). The law authorized the current process to devise a national plan for the disease. The (Alzheimer's) Advisory Council was also created as a result of the new law - it consists of stakeholders from the whole spectrum of the Alzheimer's community, as well as representatives from several relevant federal agencies. The Council has been told to provide the HHS Secretary with recommendations for a national plan.

John's added:

"This process is about changing the course of Alzheimer's disease. It is about setting the path for that change right away with an aggressive timeline. Developing an urgent, achievable and accountable strategy for Alzheimer's is about hope for millions of people today and tomorrow. What we need now is a meaningful plan with appropriate resources that, when fully implemented, will bring us from possibility to reality."

Among its several recommendations, the Advisory Council says an extra $2 billion should be spent annually on Alzheimer's research. A Council Subcommittee is looking into electing a person who is responsible and accountable for putting the National Plan into action.

Several countries, such as South Korea, France and Australia, have thorough Alzheimer's plans already in place. Experts have been commenting for a while now that the USA needs one too.

Dr. Howard Koh, HHS Assistant Secretary for Health, said in an interview with Reuters:

"We want to demonstrate that as a country we are committed to addressing this issue.

We know the projected number of patients is expected to rise in the future. We know there are far too many patients who are suffering from this devastating condition and it is affecting them and their caregivers."

Several experts comment that similar drives on cancer and HIV/AIDS have no deadlines. They add that perhaps the focus should simply be on continuing the fight and making progress. There is concern that by placing a deadline, the whole project is setting itself up for failure if no cure is found for Alzheimer's by 2025.

Secretary of State, Hillary Clinton set a goal for eliminating the disease last year, thirty years into the fight against AIDS. AIDS has received enormous amounts of funding, Alzheimer's, in contrast, has not.

Many experts say that without public funding, most pharmaceutical companies will not pursue medical breakthroughs in Alzheimer's. Earlier this week Pfizer Inc and Medivation Inc announced the end of their collaboration with Dimbebon, an experimental drug that many had hoped might improve cognitive ability in late-state Alzheimer's - the drug failed to improve signs and symptoms.

News source:medicalnewstoday

Plans to change autism definition has some worried

News of science:
Autism advocates are worrying that proposed changes to the way that autism is defined could affect the way that children and adults with the condition access treatment and services.
An expert panel appointed by the American Psychiatric Association is considering narrowing the definition of autism as it completes its fifth edition of the Diagnostic and Statistical Manual of Mental Disorders, or DSM V, as it's known.
The DSM is the standard reference book for mental health disorders and hasn't been revised in 17 years. Most expect the new edition will narrow the criteria for autism to make it more stringent.
But there is debate about how much the change will affect those with autism.
The new definition is expected to emphasize "classical autistic," or the more severe symptoms.
Under the current criteria a person can qualify for the diagnosis by exhibiting six or more of 12 behaviors. Under the proposed definition, the person would have to exhibit three deficits in social interaction and communication, and at least two repetitive behaviors.
The proposed change would bring all three diagnoses under one term: autism spectrum disorder. That means that the terms Asperger's syndrome and P.D.D.-N.O.S. (pervasive developmental disorder, not otherwise specified) would be eliminated.
The idea behind the change is that it would slow the trend of rising diagnoses.
Support services at risk
The rates of autism have surged since the 1980s, with some figures suggesting as many as one in 110 children have the disorder. Some contend that many kids with other communication and developmental problems are being unfairly lumped into autism, when they don't meet the classic definition.
But The New York Times reports that a new analysis presented Thursday at a meeting of the Icelandic Medical Association found that the changes could mean that many people currently described to have the condition would no longer meet the criteria. And that might mean they would no longer be able to access certain health, educational and social services.
But Catherine Lord, a member of the task force working on the diagnosis, disputes the analysis and tells the Times that very few people would be excluded under the change.
Leah Miltchin, the head of the board of directors at Autism Ontario, says the worry among the autism community is that if some people are excluded from the autism definition, they might no longer be able to access certain health, educational and social services.
"That is the concern that a lot of parents currently have. If you have a child with a diagnosis of Asperger's syndrome and they qualify for certain supports, when the diagnostic criteria change, they may not fit under the ASD umbrella anymore," she tells CTV News.
And yet a person with Asperger's syndrome would still need support services, she notes.
"Even if the diagnostic criteria change, the needs that are there will still be there," she says.
The revisions, now under review by a group of experts, are said to be about 90 per cent complete and due to be finalized by the end of the year.
Christina Buczek, whose 15-year-old daughter Emily has autism, says she agrees that the current definition has become pretty wide.
"I would say that with the current diagnosis of the spectrum, the umbrella term has become so wide that it's in a way meaningless," she told CTV News Channel Friday.
She says someone who is high functioning but has some communication problems is a long way from someone like her daughter, who doesn't speak at all.
"If you were to take my daughter and put her beside someone at the other end of the spectrum -- who would be maybe somebody with Asperger's – there would be very remote similarity between the two."
The changes would most affect people in some U.S. states where having Asperger syndrome or the broad diagnosis of a "pervasive development disorder" means they don't qualify for services. The changes would spell good news for some of these people who might be redefined as having autism disorder.
But others who do have Asperger's syndrome don't like the idea that they might be redefined as having autism disorder, which they worry carries more of a stigma than the term Asperger's.
ews source:ottawa.ctv

Flu scientists agree to 60-day ‘pause’ in bird-flu research

News of science:

The world’s leading influenza scientists on Friday said they will stop certain experiments on H5N1 “bird flu” for 60 days while the research community considers how much information about the highly lethal virus should be released to the public.
The decision comes a month after the U. S. government asked the journals Science and Nature to withhold details on how two laboratories made strains of H5N1 that are as deadly as the “wild” version but may be far more transmissible to people.
“We are doing this to give a little bit of breathing room to the infectious disease field, international organizations and governments,” said Ron A. M. Fouchier, a virologist in the Netherlands whose research paper is one of the ones the U.S. government wants redacted. “It is not a time for panicky actions.”
Fouchier got 38 other flu scientists around the world to sign a letter, published online by Science, announcing the self-imposed moratorium.
For the next two months, work on the lab-created bird flu will stop. There will be no studies of whether the currently approved H5N1 vaccine protects against the new strains — something that both pharmaceutical companies and public health agencies eagerly want to know. Analysis of wild H5N1 strains causing illness around the world will continue, however. So far this year there have been fatal human cases in Cambodia, Indonesia and Vietnam.
“I think it had to be done,” Robert G. Webster, a virologist at St. Jude Children’s Research Hospital in Memphis, said of the moratorium. “We have to decide on the way forward. These papers are game-changers in the influenza field.”
At the same time, the World Health Organization’s director of health security, Keiji Fukuda, confirmed that WHO will convene a meeting in Geneva next month to discuss the issue and seek consensus about how much, if any, data about lab-made flu strains should stay under wraps.
The two moves effectively make an international conversation out of what appeared to be an argument between the U.S. government and two labs along with the journals seeking to publish their findings.
“H5N1 is clearly a global issue that goes well beyond the concern of the United States,” said Anthony S. Fauci, director of the National Institute of Allergy and Infectious Diseases. He said the government supports the moratorium.
Any policies that come out of the two-month hiatus, however, are likely to be voluntary, as WHO doesn’t have the authority to ban or censor research, and it would be highly unusual for the federal government to stop a scientific paper’s publication.
H5N1, which devastates chicken flocks, first caused human disease in 1997. Since then there have been 581 confirmed cases, 342 of them fatal. Nearly all have occurred in Southeast Asia in people with close contact with infected birds. Person-to-person spread is extremely rare.
The two research groups — Fouchier’s in Rotterdam and one at the University of Wisconsin led by Yoshihiro Kawaoka — created H5N1 strains that were both lethal about 60 percent of the time and easily transmitted between ferrets, the lab animals used as surrogates for human beings in flu research.
The National Science Advisory Board for Biosecurity, created by the federal government after the 2001 anthrax letter attacks, reviewed the papers. It advised the Department of Health and Human Services that it ask the journals not to publish the methods for making the strains, and not to identify the specific gene sequences and mutations that appear responsible for the virus’s easy transmissibility.
The journals reluctantly agreed as long as provisions were made to give all the data to scientists and governments with a legitimate need for it. Who those are and how to do it will be major topics of the Geneva meeting.
News source:washingtonpost

Tiny amounts of alcohol dramatically extend a worm's life, but why?

News of science:Minuscule amounts of ethanol, the type of alcohol found in alcoholic beverages, can more than double the life span of a tiny worm known as Caenorhabditis elegans, which is used frequently as a model in aging studies, UCLA biochemists report. The scientists said they find their discovery difficult to explain.
"This finding floored us — it's shocking," said Steven Clarke, a UCLA professor of chemistry and biochemistry and the senior author of the study, published Jan. 18 in the online journal PLoS ONE, a publication of the Public Library of Science.
In humans, alcohol consumption is generally harmful, Clarke said, and if the worms are given much higher concentrations of ethanol, they experience harmful neurological effects and die, other research has shown.
"We used far lower levels, where it may be beneficial," said Clarke, who studies the biochemistry of aging.
The worms, which grow from an egg to an adult in just a few days, are found throughout the world in soil, where they eat bacteria. Clarke's research team — Paola Castro, Shilpi Khare and Brian Young — studied thousands of these worms during the first hours of their lives, while they were still in a larval stage. The worms normally live for about 15 days and can survive with nothing to eat for roughly 10 to 12 days.
"Our finding is that tiny amounts of ethanol can make them survive 20 to 40 days," Clarke said.
Initially, Clarke's laboratory intended to test the effect of cholesterol on the worms. "Cholesterol is crucial for humans," Clarke said. "We need it in our membranes, but it can be dangerous in our bloodstream."
The scientists fed the worms cholesterol, and the worms lived longer, apparently due to the cholesterol. They had dissolved the cholesterol in ethanol, often used as a solvent, which they diluted 1,000-fold.
"It's just a solvent, but it turns out the solvent was having the longevity effect," Clarke said. "The cholesterol did nothing. We found that not only does ethanol work at a 1-to-1,000 dilution, it works at a 1-to-20,000 dilution. That tiny bit shouldn't have made any difference, but it turns out it can be so beneficial."
How little ethanol is that?
"The concentrations correspond to a tablespoon of ethanol in a bathtub full of water or the alcohol in one beer diluted into a hundred gallons of water," Clarke said.
Why would such little ethanol have such an effect on longevity?
"We don't know all the answers," Clarke acknowledged. "It's possible there is a trivial explanation, but I don't think that's the case. We know that if we increase the ethanol concentration, they do not live longer. This extremely low level is the maximum that is beneficial for them."
The scientists found that when they raised the ethanol level by a factor of 80, it did not increase the life span of the worms.
The research raises, but does not answer, the question of whether tiny amounts of ethanol can be helpful for human health. Whether this mechanism has something in common with findings that moderate alcohol consumption in humans may have a cardiovascular health benefit is unknown, but Clarke said the possibilities are intriguing.
In follow-up research, Clarke's laboratory is trying to identify the mechanism that extends the worms' life span.
About half the genes in the worms have human counterparts, Clarke said, so if the researchers can identify a gene that extends the life of the worm, that may have implications for human aging.
"It is important for other scientists to know that such a low concentration of the widely used solvent ethanol can have such a big effect in C. elegans," said lead author Paola Castro, who conducted the research as an undergraduate in Clarke's laboratory before earning a bachelor's degree in biochemistry from UCLA in 2010 and joining the Ph.D. program in bioengineering at UC Santa Cruz. "What is even more interesting is the fact that the worms are in a stressed developmental stage. At high magnifications under the microscope, it was amazing to see how the worms given a little ethanol looked significantly more robust than worms not given ethanol."
"While the physiological effects of high alcohol consumption have been established to be detrimental in humans, current research shows that low to moderate alcohol consumption, equivalent to one or two glasses of wine or beer a day, results in a reduction in cardiovascular disease and increased longevity," said co-author Shilpi Khare, a former Ph.D. student in UCLA's biochemistry and molecular biology program who is now a postdoctoral fellow at the Genomics Institute of the Novartis Research Foundation in San Diego. "While these benefits are fascinating, our understanding of the underlying biochemistry involved in these processes remains in its infancy.
"We show that very low doses of ethanol can be a worm 'lifesaver' under starvation stress conditions," Khare added. "While the mechanism of action is still not clearly understood, our evidence indicates that these 1 millimeter–long roundworms could be utilizing ethanol directly as a precursor for biosynthesis of high-energy metabolic intermediates or indirectly as a signal to extend life span. These findings could potentially aid researchers in determining how human physiology is altered to induce cardio-protective and other beneficial effects in response to low alcohol consumption."
Clarke's laboratory identified the first protein-repair enzyme in the early 1980s, and his research has shown that repairing proteins is important to cells. In the current study, the biochemists reported that life span is significantly reduced under stress conditions in larval worms that lack this repair enzyme. (More than 150 enzymes are involved in repairing DNA damage, and about a dozen protein-repair enzymes have been identified.)
"Our molecules live for only weeks or months," Clarke said. "If we want to live long lives, we have to outlive our molecules. The way we do that is with enzymes that repair our DNA — and with proteins, a combination of replacement and repair."
Researcher Brian Young, now an M.D./Ph.D. student at the David Geffen School of Medicine at UCLA, is a co-author on the research. The research was federally funded by the National Institutes of Health's National Institute of General Medical Sciences.
News source:physorg

Senate vote on online piracy bill delayed (Update 2)

News of science:US Senate leaders announced Friday they were delaying next week's vote on an anti-online piracy bill that Wikipedia, Google and other Web giants have denounced as a threat to Internet freedom.

"In light of recent events, I have decided to postpone Tuesday's vote on the Protect IP Act," US Senate majority leader Harry Reid said in a statement two days after a wave of online protests against the bill swept the Internet.
"There is no reason that the legitimate issues raised by many about this bill cannot be resolved," Reid said. "I am optimistic that we can reach a compromise in the coming weeks."
Reid's announcement came amid eroding congressional support for the bills -- the Protect IP Act (PIPA) in the Senate and the Stop Online Piracy Act (SOPA) in the House of Representatives -- intended to crack down on online piracy of movies and music and the sale of counterfeit goods.
Republican House speaker John Boehner said Wednesday there was a "lack of consensus at this point" on the House version of the bill and it would need further work in committee.
Wikipedia shut down the English-language version of its online encyclopedia for 24 hours on Wednesday to protest the legislation.
Google blotted out the logo on its US home page with a black banner and published an exhortation to users to "Tell Congress: Please don't censor the Web!"
Hundreds of other websites joined in the protest and Google said more than seven million people in the United States had signed an online petition against the bills.

Enlarge

Protesters demonstrate against the proposed Stop Online Piracy Act (SOPA) and Protect IP Act (PIPA) in New York City on January 18. US Senate majority leader Harry Reid said Friday that he was delaying next week's scheduled vote on a controversial bill aimed at cracking down on online piracy.

The draft legislation has won the backing of Hollywood, the music industry, entertainment giants like Rupert Murdoch's News Corp., the National Association of Manufacturers, the US Chamber of Commerce and others. But the bills have come under fire from online companies and digital rights groups for allegedly paving the way for US authorities to shut down websites accused of online piracy, including foreign sites, without due process.
On Thursday, US authorities shut down Megaupload.com, one of the world's largest file-sharing sites, and charged seven people in what they called one of "the largest criminal copyright cases ever brought by the United States."
The shutdown of Megaupload triggered a wave of retaliatory attacks by the online hacktivist group Anonymous, which temporarily disabled the websites of the Justice Department, FBI and Recording Industry Association of America.
In his statement, Reid said "counterfeiting and piracy cost the American economy billions of dollars and thousands of jobs each year, with the movie industry alone supporting over 2.2 million jobs.
"We must take action to stop these illegal practices," he said. "We live in a country where people rightfully expect to be fairly compensated for a day's work."
Reid urged a co-sponsor of the bill, Senator Patrick Leahy, to "continue engaging with all stakeholders to forge a balance between protecting Americans' intellectual property, and maintaining openness and innovation on the Internet."
Another co-sponsor of the Protect IP Act, Senator Marco Rubio, withdrew his support for the bill on Wednesday saying Congress should "avoid rushing through a bill that could have many unintended consequences" on the Internet.
Other lawmakers also distanced themselves from the legislation, including influential Republican Senator Orrin Hatch of Utah.
"After listening to concerns on both sides of the debate over #PIPA, it is simply not ready for prime time," Hatch said on Twitter.
The controversy has pitted Hollywood against Silicon Valley, forcing members of Congress to try to walk a fine line between two powerful forces, and led to an unprecedented outpouring of coordinated protest on the Web.
White House spokesman Jay Carney said Wednesday that the problem of online piracy needs to be tackled but "in a way which does not impinge upon a free and open Internet."
 News source:physorg

Web players enlist for coordinated June 6 launch of IPv6

News of science:The Internet Society has made it official. Last June’s dress rehearsals are over; June 6 of this year is official World IPv6 Launch Day, where a new system of numerical addresses will be used to connect users to websites. A lineup of supporters for the launch date was announced this week. Seven ISPs, two home networking equipment manufacturers, and a number of web companies at the time of the writing have come forward to pledge enabling the new protocol. 
The ISPs participating in the World IPv6 Launch have agreed that at least 1% of their wireline residential subscribers who visit participating websites will be able to do so via IPv6 by June 6. The ISPs who have promised this are AT&T. Comcast, XS4all, Free Telecom, Internode, KDDI, and Time Warner Cable.
In the case of home-network equipment manufacturers. Cisco and D-Link say they aim to enable IPv6 on their home router products. Facebook, Google, Microsoft Bing, and Yahoo are the four websites that have announced support for IPv6 for their web sites. IPv6, popularly tagged as new phone numbers for the world’s web sites, is the Internet address system that replaces protocol IPv4, which is about to run out of space.
Every device connected to the Internet is assigned an IPO address, a string of numbers to allow other devices to see where the data is from and should be sent to. The old systems has about 4 billion such IP addresses; the new system, IPv6, will have over 340 trillion trillion trillion Internet addresses.
While the space problem is solved, a transition of this nature is no flip-a-switch deal, hardly seamless, for one fundamental reason. IPv6 is incompatible with IPv4. The transition will involve work on the part of operators to support the new world web order. According to the Internet Society, most Internet users will not feel any effect. According to the Internet Society's site, “in rare cases" users may still experience connectivity issues when visiting participating websites. “Users can visit an IPv6 test site to check if their connectivity will be impacted. If the test indicates a problem, they can disable IPv6 or ask their ISPs to help fix the problem.”
System technicians, meanwhile, will probably hear the term “dual-stacked” quite often this year before and after the June event. Facebook will be dual-stacked, according to reports, for example, meaning it will support access via IPv4 and IPv6.
Google's Erik Kline, IPv6 Software Engineer, Tokyo, in this week's announcement of its participation on June 6, said that “if your ISP isn’t on board yet, ask them to join us. It will take years for the Internet to transition fully.”
Kline said that the majority of users shouldn’t notice, "but check out our test page and help article if you think you might run into difficulty.”
The Internet Society which is organizing the June 6 day, would be the first to acknowledge that this transition is going to take some work. Leslie Daigle, the Internet Society's chief information technology officer, told NetworkWorld that the June day is more of a start than deadline date so that by that point the participants have agreed to start their production deployments.
News source:PhysOrg

New research suggests birth weight plays a role in autism spectrum disorder

News of science:Although the genetic basis of autism is now well established, a growing body of research also suggests that environmental factors may play a role in this serious developmental disorder affecting nearly one in 100 children. Using a unique study design, a new study suggests that low birth weight is an important environmental factor contributing to the risk of autism spectrum disorder (ASD).
"Our study of discordant twins -- twin pairs in which only one twin was affected by ASD -- found birth weight to be a very strong predictor of autism spectrum disorder," said Northwestern University researcher Molly Losh. Losh, who teaches and conducts research in Northwestern's School of Communication, is lead author of the study that will be published in the journal Psychological Medicine and is now available online.
Prior twin studies have shown that when one identical twin had ASD, the other twin was much more likely to have ASD than not. "Because identical twins share virtually 100 percent of their genes, this is strong evidence for the role of genetics in autism," said Losh. "Yet it is not 100 percent the case that ASD affects both identical twins in a twin pair."
"That only one twin is affected by ASD in some identical twin pairs suggests that environmental factors may play a role either independently or in interaction with autism risk genes," she added. "And because autism is a developmental disorder impacting brain development early on, it suggests that prenatal and perinatal environmental factors may be of particular importance."
The researchers found that lower birth weight more than tripled the risk for autism spectrum disorder in identical twin pairs in which one twin had ASD and the other did not.
To control for shared genetic and environmental factors, the researchers used a co-twin control study design in which the ASD-affected twin served as the case and the unaffected twin served as the control. They found the risk for autism spectrum disorder rose 13 percent for every 100 gram- (3.5 ounce-) decrease in birth weight.
"There's been a great deal of misinformation about the causes of autism -- from the 1950s misconception that the distant maternal behavior of what were dubbed "refrigerator mothers" was at fault to the ill-informed myth that vaccines can cause autism," said Losh.
Losh and her colleagues' findings add to a growing body of knowledge about the complex causes of autism and suggest that birth weight could be one of the environmental features that interacts with underlying genetic predisposition to autism.
Losh, who directs Northwestern's Neurodevelopmental Disabilities Laboratory, warned that the findings from twin studies might not extend to singletons, as the prenatal and perinatal conditions for twins and singletons differ in important ways.
The researchers studied a population-based sample of 3,725 same-sex twin pairs that were part of the Swedish Twin Registry's Child and Adolescent Twin Study that was directed by Paul Lichtenstein of Sweden's Karolinska Institute. The discordant twins they studied were pairs in which one twin was more than 400 grams (about 14 ounces) or at least 15 percent heavier at birth than the other.
In addition to Lichtenstein, Losh -- the Jane Steiner Hoffman and Michael Hoffman Assistant Professor of Communication Sciences and Disorders -- co-authored "Lower birth weight indicates higher risk of autistic traits in discordant twins," with D. Esserman and P.F. Sullivan (University of North Carolina at Chapel Hill), H. Anckarsater (Lund University, Sweden) and P. Lichtenstein (Karolinska Institute, Sweden).
News source:medicalxpress

World timekeepers split on scrapping leap second

News of science:Timekeepers meeting in Geneva failed to agree Thursday on a proposal to abolish a 40-year-old practice of adding the occasional second to world time.
The International Telecommunication Union put off a decision, saying more study was needed into whether to scrap the leap second -- the extra moment added to atomic clocks to keep them in sync with the earth's rotation, which is slowed by the gravitational pull of the Sun and the Moon.
"The decision that we will take is that it is not approved and the matter is to be referred to study group seven for more study," Alan Jamieson, chairman of the ITU's Radiocommunication Assembly, said at the close of the meeting.
The decade-long debate has split ITU member countries.
Every time a second is added, the world's computers need to be manually adjusted, a costly practice that also boosts the risk of error.
Without the leap second, hi-tech clocks would race ahead of solar time, amounting to a discrepancy of about 15 seconds every 100 years, experts believe.
"The social, legal, religious implications (of scrapping the leap second) have not been studied properly," said British representative Stephen Bond, while the US said the increasing use of satellite-based navigation systems favoured its suppression.
A leap second has been added on 24 occasions since the ITU defined Coordinated Universal Time (UTC) 40 years ago.
When required, they are always introduced at midnight on June 30 or December 31.
Seventy countries were represented at Thursday's gathering, with the US, France and Japan among those favouring the scrapping of the leap second, while Britain, China and Canada said further study was needed.
"The use of these seconds introduces the possibility of technical problems each time they are inserted into UTC," said US representative Dick Beaird.
"This can impact the safety and reliability of systems dependent on precision time keeping.
"Systems for space activity, global navigation, satellite systems and so forth require a continuous, uninterrupted time reference."
Bond said the decision was one of "great significance" that would be reflected on by future generations and its approval would be premature.
"The common public understanding of the civil time of day is that it is closely linked to the earth's rotation," he said.
"There may be public opposition to ending the linkage and the fact that the day will no longer be matched by a single rotation of the earth."
The future of the leap second will be further debated at the ITU's World Radiocommunication Conference beginning next week.
News source:physorg

Scientists make progress in assessing tornado seasons

News of science:Meteorologists can see a busy hurricane season brewing months ahead, but until now there has been no such crystal ball for tornadoes, which are much smaller and more volatile. This information gap took on new urgency after tornadoes in 2011 killed more than 550 people, more than in the previous 10 years combined, including a devastating outbreak in April that racked up $5 billion in insured losses. Now, a new study of short-term climate trends offers the first framework for predicting tornado activity up to a month out with current technology, and possibly further out as climate models improve, giving communities a chance to plan. The study may also eventually open a window on the question of whether tornadoes are growing more frequent due to long-term climate warming.
"Understanding how climate shapes tornado activity makes forecasts and projections possible and allows us to look into the past and understand what happened," said lead author Michael Tippett, a climate scientist at Columbia University's International Research Institute for Climate and Society (IRI).
Packing winds of up to 300 miles per hour, tornadoes descend when warm, moist air collides with cold, dry air, creating a vortex as the two masses move around each other. The U.S. Midwest is the twister capital of the world, where cold air blowing east from the Rockies habitually hits tropical air moving north from the Gulf of Mexico. Tornadoes appear to be growing more frequent as climate warms, but it is uncertain whether there is a connection; they are small and hard to count, and recently improved reporting may also explain the increase.
Lack of an accurate long-term tornado record makes it hard to know the truth, and has also hampered scientists' ability to relate tornadoes to cyclical weather patterns that could aid in forecasting. While individual hurricanes can be spotted days in advance, tornadoes appear with much less warning. A tornado watch typically gives only a few hours' notice that dangerous conditions are brewing, while warning of an actual tornado bearing down may give people just a few minutes to get out of the way.
Tippett, a seasonal forecasting expert, had already built statistical models to understand how climate change might affect hurricanes by adding more heat and moisture to the air. But applying the same methods to something as tiny and complicated as a twister is trickier, said study coauthor Adam Sobel, an atmospheric scientist with joint appointments at Columbia's Lamont-Doherty Earth Observatory and School of Engineering and Applied Science. "A tornado is not a lot bigger than the house it has just destroyed," he said. "It's a small thing and short-lived."
Combing through 30 years of data, Tippett and his colleagues began looking for patterns linking climate and tornadoes. By comparing average atmospheric conditions with average monthly tornado counts in regions across the United States, they identified two parameters that seemed closely associated with monthly tornado activity: rain associated with strong updrafts; and helicity, which measures the tendency of winds to spin those updrafts.
They then looked to see if they could "predict" the tornado activity of individual months from 1979 to 2010 from a simple index based on each month's average wind and rain parameters. The index correlated significantly with the observed numbers of tornadoes in all months except September and October. Moreover, the National Oceanic and Atmospheric Administration (NOAA) system for making seasonal forecasts, known as the Climate Forecast System (CFS), was able to use the index to forecast monthly tornado activity with some success up to a month in advance. This success, especially notable in June, is the first evidence for the predictability of monthly tornado activity.
Harold Brooks, a NOAA tornado expert not involved in the study said the forecast technique worked where others have failed because the CFS produced higher resolution results. "The real breakthrough is that CFS is skillful enough at the right scale," he said. With greater lead time, communities and relief agencies could prepare, he said. "It's not like the hurricane problem where we can tell people to evacuate. But if I'm a state emergency manager I might be really interested in knowing at the end of March that by the end of April we could have a big problem. You could be better prepared with generators and supplies."
Tippett said the next steps are to improve the index's reliability in the fall; to better understand why the forecasts work; and to apply the index to projections of future climate. "Before you can use an index to diagnose future climate, you have to be confident that it explains the observed variability," he said.
News source:physorg

Where you vote may influence how you vote, researchers find

News of  science:Passersby who stopped to answer surveys taken next to churches in the Netherlands and England reported themselves as more politically conservative and more negative toward non-Christians than did people questioned within sight of government buildings — a finding that may be significant when it comes to voting, according to a Baylor University study.
The study, published online in the International Journal for the Psychology of Religion, adds to a growing body of evidence that religious "priming" can influence both religious and nonreligious people, Baylor researchers said. Priming occurs when a stimulus such as a verbal or a visual cue — for example, the buildings that were in participants' line of vision during questioning — influences a response.
The findings are significant in that churches and other buildings affiliated with a religious group are among the most common polling places, said psychologist Jordan LaBouff, Ph.D., lead author for the Baylor study.
"The important finding here is that people near a religious building reported slightly but significantly more conservative social and political attitudes than similar people near a government building," said co-author Wade Rowatt, Ph.D., associate professor of psychology and neuroscience at Baylor. "In a close election, the place where people vote — a school, a church, a government building — could affect the outcome . For example, a higher percentage of people voting in a church instead of a school might vote for a conservative candidate or proposition."
He noted that a Stanford University study of an Arizona school funding referendum in 2000 showed that voters polled in schools were more likely to support a state tax increase than were those polled in churches or community centers. That study was published in 2008 in the Proceedings of the National Academy of Science.
The Baylor study "raises questions about how our spaces can influence our attitudes," said LaBouff, a psychology lecturer at the University of Maine who collaborated on the research while a doctoral candidate at Baylor. "We should look carefully at places where important decisions are made."
He noted that while those conducting the survey made certain that the church or government building was within sight of the participant, they did not question people who were entering or leaving the buildings.
"We didn't want people who were there for the express purpose of going into a church, because that might mean they were inherently more religious," LaBouff said.
Another finding was that regardless of the setting, negativity toward Christians was not statistically significant among the culturally diverse group of passersby.
"Interestingly, these more negative attitudes toward non-Christian groups were held by a very diverse — and largely non-Christian — sample," LaBouff said. "The only people who weren't viewed negatively were Christians. They were a non-factor."
Passersby were asked to rate "outgroups" — those who were different from themselves in terms of culture and/or religion. Groups listed included rich, poor, Christian, Jewish, Muslim, gay men, lesbian women, Africans, Asians, Europeans and Arabs. Participants were asked to rate their feelings of "coolness" or "warmness" toward certain groups on a scale of 1 to 10, with 10 being the warmest.
Survey participants were diverse and multicultural — 99 individuals from more than 30 countries. They were questioned by Baylor students during a study-abroad tour, and Baylor psychologists in the College of Arts & Sciences analyzed the data collected by the students in an advanced research methods class.
In Maastricht in the Netherlands, passersby were surveyed outside the Basilica of Saint Servatius and Maastricht Town Hall; in London, they were surveyed outside Westminster Abbey and Parliament. All the structures are located along major pedestrian paths.
News source:physorg

Gaseous ring around young star raises questions

News of science:Astronomers have detected a mysterious ring of carbon monoxide gas around the young star V1052 Cen, which is about 700 light years away in the southern constellation Centaurus. The ring is part of the star’s planet-forming disk, and it’s as far from V1052 Cen as Earth is from the sun. Discovered with the European Southern Observatory's Very Large Telescope, its edges are uniquely crisp.
Carbon monoxide is often detected near young stars, but the gas is usually spread through the planet-forming disk. What’s different about this ring is that it is shaped more like a rope than a dinner plate, said Charles Cowley, professor emeritus in the University of Michigan who led the international research effort.
“It’s exciting because this is the most constrained ring we've ever seen, and it requires an explanation,” Cowley said. “At present time, we just don't understand what makes it a rope rather than a dish.”  Perhaps magnetic fields hold it in place, the researchers say. Maybe “shepherding planets” are reining it in like several of Saturn’s moons control certain planetary rings.
“What makes this star so special is its very strong magnetic field and the fact that it rotates extremely slow compared to other stars of the same type,” said Swetlana Hubrig, of the Leibniz Institute for Astrophysics Potsdam (AIP), Germany.
The star’s unique properties first caught the researchers’ attention in 2008, and they have been studying it intensely ever since.
Understanding the interaction between central stars, their magnetic fields, and planet-forming disks is crucial for astronomers to reconstruct the solar system's history. It is also important to account for the diversity of the known planetary systems beyond our own. This new finding raises more questions than it answers about the late stages of star and solar system formation.
“Why do turbulent motions not tear the ring apart?” Cowley wondered. “How permanent is the structure? What forces might act to preserve it for times comparable to the stellar formation time itself?”
The team is excited to have found an ideal test case to study this type of object.
“This star is a gift of nature,” Hubrig said.
The findings are newly published online in Astronomy and Astrophysics. The paper is titled “The narrow, inner CO ring around the magnetic Herbig Ae star HD 101412.” Authors are from the University of Michigan, the Leibniz Institute for Astrophysics Potsdam (AIP) in Germany, the Istituto Nazionale die Astrofisica in Italy and the European Southern Observatory.
News source:physorg

Scientists make first-ever observations of comet's demise deep inside solar atmosphere

News of science:On July 6, 2011, a comet was caught doing something never seen before: die a scorching death as it flew too close to the sun. That the comet met its fate this way was no surprise – but the chance to watch it first-hand amazed even the most seasoned comet watchers.
"Comets are usually too dim to be seen in the glare of the sun's light," says Dean Pesnell at NASA's Goddard Space Flight Center in Greenbelt, Md., who is the project scientist for NASA's Solar Dynamic Observatory (SDO), which snapped images of the comet. "We've been telling people we'd never see one in SDO data."
But an ultra bright comet, from a group known as the Kreutz comets, overturned all preconceived notions. The comet can clearly be viewed moving in over the right side of the sun, disappearing 20 minutes later as it evaporates in the searing heat. The movie is more than just a novelty. As detailed in a paper in Science magazine appearing January 20, 2012, watching the comet's death provides a new way to estimate the comet's size and mass. The comet turns out to be somewhere between 150 to 300 feet long and have about as much mass as an aircraft carrier.
"Of course, it's doing something very different than what aircraft carriers do," says Karel Schrijver, a solar scientist at Lockheed Martin in Palo Alto, Calif., who is the first author on the Science paper and is the principal investigator of the Atmospheric Imaging Assembly instrument on SDO, which recorded the movie. "It was moving along at almost 400 miles per second through the intense heat of the sun – and was literally being evaporated away."

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SDO's AIA instrument captured the first ever video of a comet passing directly in front of the sun in the early morning of July 6, 2011. The comet comes in from the right and is very faint (recommend viewing full screen). Credit: NASA/SDO

Typically, comet-watchers see the Kreutz-group comets only through images taken by coronagraphs, a specialized telescope that views the Sun's fainter out atmosphere, or corona, by blocking the direct blinding sunlight with a solid occulting disk. On average a new member of the Kreutz family is discovered every three days, with some of the larger members being observed for some 48 hours or more before disappearing behind the occulting disk, never to be seen again. Such "sun-grazer" comets obviously destruct when they get close to the sun, but the event had never been witnessed. The journey to categorizing this comet began on July 6, 2011 after Schrijver spotted a bright comet in a coronagraph produced by the SOlar Heliospheric Observatory (SOHO). He looked for it in the SDO images and much to his surprise he found it. Soon a movie of the comet circulated to comet and solar scientists, eventually making a huge splash on the Internet as well.
Karl Battams, a scientist with the Naval Research Laboratory in Washington, DC, who has extensively observed comets with SOHO and is also an author on the paper, was skeptical when he first received the movie. "But as soon as I watched it, there was zero doubt," he says. "I am so used to seeing comets simply disappearing in the SOHO images. It was breathtaking to see one truly evaporating in the corona like that."
After the excitement, the scientists got down to work. Humans have been watching and recording comets for thousands of years, but finding their dimensions has typically required a direct visit from a probe flying nearby. This movie offered the first chance to measure such things from afar. The very fact that the comet evaporated in a certain amount of time over a certain amount of space means one can work backward to determine how big it must have been before hitting the sun's atmosphere.
The Science paper describes the comet and its last moments as follows: It was traveling some 400 miles per second and made it to within 62,000 miles of the sun's surface before evaporating. Before its final death throes, in the last 20 minutes of its existence when it was visible to SDO, the comet was some 100 million pounds, had broken up into a dozen or so large chunks with sizes between 30 to 150 feet, embedded in a "coma" -- that is the fuzzy cloud surrounding the comet -- of approximately 800 miles across, and followed by a glowing tail of about 10,000 miles in length.
It is actually the coma and tail of the comet being seen in the video, not the comet's core. And close examination shows that the light in the tail pulses, getting dimmer and brighter over time. The team speculates that the pulsing variations are caused by successive breakups of each of the individual chunks that made up the comet material as it fell apart in the Sun's intense heat.
"I think this is one of the most interesting things we can see here," says Lockheed's Schrijver. "The comet's tail gets brighter by as much as four times every minute or two. The comet seems first to put a lot of material into that tail, then less, and then the pattern repeats." Figuring out the exact details of why this happens is but one of the mysteries remaining about this comet movie. High on the list is to answer the not-so-simple question of why we can see the comet at all. Certainly, there are a few basic characteristics of this situation that help. For one, this comet was big enough to survive long enough to be seen, and its orbit took it right across the face of the Sun. It was also, says Battams, probably one of the top 15 brightest comets seen by SOHO, which has observed over 2,100 sun-grazing comets to date. The SDO cameras, in of themselves, also contributed a great deal: despite being far away and relatively small compared to the sun, the comet showed up clearly on SDO's high definition imager. This imager, called the Atmospheric Imaging Assembly (AIA) takes a picture every 12 seconds so the movement of the comet across the face of the sun could be continuously watched. Most other similar instruments capture images every few minutes, which makes it hard to track the movement of an object that's only visible for 20 minutes.
But ultimately, the fact that one can see this comet against the background of the sun means there is some physical process not yet understood. "Normally," says Goddard's Pesnell, "a comet passing in front of the sun absorbs the light from the sun. We would have expected a black spot against the sun, not a bright one. And there's not enough stuff in the corona to make it glow, the way a meteor does when it goes into Earth's atmosphere. So one of the really big questions is why do we see it at all?"
Figuring out this question should offer information not only about material in the comet, but also about the sun's atmosphere – and so this opens up the door to a new niche of study. Assuming, of course, that one can spot some more comets. So far SDO has only seen the one passing in front of the sun, though SDO did spot Comet Lovejoy traveling through the corona, as it went behind the sun and reappeared.
Stay tuned, as new sun-grazing comets appear every few days...

Hearty bacteria help make case for life in the extreme

News of science:The bottom of a glacier is not the most hospitable place on Earth, but at least two types of bacteria happily live there, according to researchers.
The bacteria -- Chryseobacterium and Paenisporosarcina -- showed signs of respiration in ice made in the laboratory that was designed to simulate as closely as possible the temperatures and nutrient content found at the bottom of Arctic and Antarctic glaciers, said Corien Bakermans, assistant professor of microbiology, Penn State Altoona. She said that carbon dioxide levels in the laboratory-made ice containing the bacteria, which were collected from glaciers in Greenland and Antarctica, indicated that respiration was occurring at temperatures ranging from negative 27 to positive 24 degrees Fahrenheit.
Bakermans, who worked with Mark Skidmore, associate professor of geology, Montana State University, determined the level of respiration by measuring the amount of carbon dioxide in the laboratory-made ice.
While humans obtain energy from sugar, the bacteria in this experiment used acetate, a form of vinegar. Like human respiration, the microbes take in the molecules, extract energy from them and breathe out carbon dioxide as a waste product.
Bakermans said the study may have implications for the search for life on other planets, like Mars, because some places on Mars are in the same temperature range as the temperature levels recorded during the experiment.
"Although there are a lot of other factors involved for life to take hold on other planets," Bakermans said, "we can still say that if microbes on Earth can do this, then there's the potential, at least, that microbes can do this on Mars."
Glaciers and ice sheets represent large ecosystems that cover more than 10 percent of the Earth and contain approximately 78 percent of the world's fresh water.
The researchers, who reported their findings in a recent issue of Environmental Microbiology Reports, said that respiration was reported at all temperatures examined.
The respiration rate of the microbes increased as the temperature rose. While the respiration rates of the bacteria are slow compared to the human respiration, the microbes could maintain cell structure and viability throughout the observed temperature range.
The researchers also performed a staining test to measure reproduction and cell viability. When cells are alive or dead, they leave a chemical footprint of those states. By applying stains to the bacteria in the laboratory-made ice, the researchers can find those chemicals and determine if the cells are alive and healthy.
Bacteria seem to grow best in cracks and crevices within the ice, Bakermans said. The cracks in the ice create channels that allow water and nutrients to circulate.
"It's hard for nutrients to be exchanged in the ice," Bakermans said. "But these channels appear to give the microbes access to nutrients."
The bottom of glaciers may be more hospitable for the microbes than other parts of the glacier because the areas draw warmth and nutrients from the earth, Bakermans said.
News source:physorg

When it comes to accepting evolution, gut feelings trump facts

News of science:For students to accept the theory of evolution, an intuitive "gut feeling" may be just as important as understanding the facts, according to a new study.
In an analysis of the beliefs of biology teachers, researchers found that a quick intuitive notion of how right an idea feels was a powerful driver of whether or not students accepted evolution—often trumping factors such as knowledge level or religion.
"The whole idea behind acceptance of evolution has been the assumption that if people understood it – if they really knew it – they would see the logic and accept it," said David Haury, co-author of the new study and associate professor of education at Ohio State University.
"But among all the scientific studies on the matter, the most consistent finding was inconsistency. One study would find a strong relationship between knowledge level and acceptance, and others would find no relationship. Some would find a strong relationship between religious identity and acceptance, and others would find less of a relationship."
"So our notion was, there is clearly some factor that we're not looking at," he continued. "We're assuming that people accept something or don't accept it on a completely rational basis. Or, they're part of a belief community that as a group accept or don't accept. But the findings just made those simple answers untenable."
Haury and his colleagues tapped into cognitive science research showing that our brains don't just process ideas logically—we also rely on how true something feels when judging an idea. "Research in neuroscience has shown that when there's a conflict between facts and feeling in the brain, feeling wins," he says.
The researchers framed a study to determine whether intuitive reasoning could help explain why some people are more accepting of evolution than others. The study, published in the Journal of Research in Science Teaching, included 124 pre-service biology teachers at different stages in a standard teacher preparation program at two Korean universities.
First, the students answered a standard set of questions designed to measure their overall acceptance of evolution. These questions probed whether students generally believed in the main concepts and scientific findings that underpin the theory.
Then the students took a test on the specific details of evolutionary science. To show their level of factual knowledge, students answered multiple-choice and free-response questions about processes such as natural selection. To gauge their "gut" feelings about these ideas, students wrote down how certain they felt that their factually correct answers were actually true.
The researchers then analyzed statistical correlations to see whether knowledge level or feeling of certainty best predicted students' overall acceptance of evolution. They also considered factors such as academic year and religion as potential predictors.
"What we found is that intuitive cognition has a significant impact on what people end up accepting, no matter how much they know," said Haury. The results show that even students with greater knowledge of evolutionary facts weren't likelier to accept the theory, unless they also had a strong "gut" feeling about those facts.
When trying to explain the patterns of whether people believe in evolution or not, "the results show that if we consider both feeling and knowledge level, we can explain much more than with knowledge level alone," said Minsu Ha, lead author on the paper and a Ph.D. candidate in the School of Teaching and Learning.
In particular, the research shows that it may not be accurate to portray religion and science education as competing factors in determining beliefs about evolution. For the subjects of this study, belonging to a religion had almost no additional impact on beliefs about evolution, beyond subjects' feelings of certainty.
These results also provide a useful way of looking at the perceived conflict between religion and science when it comes to teaching evolution, according to Haury. "Intuitive cognition not only opens a new door to approach the issue," he said, "it also gives us a way of addressing that issue without directly questioning religious views."
When choosing a setting for their study, the team found that Korean teacher preparation programs were ideal. "In Korea, people all take the same classes over the same time period and are all about the same age, so it takes out a lot of extraneous factors," said Haury. "We wouldn't be able to find a sample group like this in the United States."
Unlike in the U.S., about half of Koreans do not identify themselves as belonging to any particular religion. But according to Ha, who is from Korea, certain religious groups consider the topic of evolution just as controversial as in the U.S.
To ensure that their results were relevant to U.S. settings, the researchers compared how the Korean students did on the knowledge tests with previous studies of U.S. students. "We found that the both groups were comparable in terms of the overall performance," said Haury.
For teaching evolution, the researchers suggest using exercises that allow students to become aware of their brains' dual processing. Knowing that sometimes what their "gut" says is in conflict with what their "head" knows may help students judge ideas on their merits.
"Educationally, we think that's a place to start," said Haury. "It's a concrete way to show them, look—you can be fooled and make a bad decision, because you just can't deny your gut."
Ha and Haury collaborated on this study with Ross Nehm, associate professor of education at the Ohio State University. The research was funded by the National Science Foundation.
News source:physorg

'Pulverized' chromosomes linked to cancer?

News of science:They are the Robinson Crusoes of the intracellular world -- lone chromosomes, whole and hardy, stranded outside the nucleus where their fellow chromosomes reside. Such castaways, each confined to its own "micronucleus," are often found in cancer cells, but scientists haven't known what role, if any, they play in the cancer process.
In a paper published online on Jan. 18 by the journal Nature, Dana-Farber Cancer Institute researchers have mapped out a mechanism by which micronuclei could potentially disrupt the chromosomes within them and produce cancer-causing gene mutations. The findings may point to a vulnerability in cancer cells that could be attacked by new therapies.
"The most common genetic change in cancer is the presence of an incorrect number of intact chromosomes within cancer cells -- a condition known as aneuploidy," says Dana-Farber's David Pellman, MD, the study's senior author. "The significance of aneuploidy has been hard to pin down, however, because little is known about how it might trigger tumors. In contrast, the mechanism by which DNA damage and broken chromosomes cause cancer is well established -- by altering cancer genes in a way that spurs runaway cell division.
"The new study demonstrates one possible chain of events by which aneuploidy and specifically 'exiled' chromosomes could lead to cancer-causing mutations, with potential implications for cancer prevention and treatment," says Pellman, who is a Howard Hughes Medical Institute investigator and the Margaret M. Dyson Professor of Pediatric Oncology at Dana-Farber, Children's Hospital Boston and Harvard Medical School.
Whole chromosomes can end up outside the nucleus as a result of a glitch in cell division. In normal division, a cell duplicates its chromosomes and dispatches them to the newly forming daughter cells: the original set to one daughter, the twin set to the other. For a variety of reasons, the chromosomes sometimes aren't allocated evenly -- one daughter receives an extra one, the other is short one. Unlike the rest of the chromosomes, these stragglers sometimes don't make it to the nucleus. Instead, they're marooned elsewhere within the cell and become wrapped in their own membrane, forming a micronucleus.
"In some respects, micronuclei are similar to primary nuclei," Pellman remarks, "but much about their function and composition is unknown. Previous studies differ on whether micronuclei replicate or repair their chromosomes as normal nuclei do. The ultimate fate of these chromosomes is unclear as well: Are they passed on to daughter cells during cell division or are they somehow eliminated as division proceeds?"
One clue that odd-man-out chromosomes themselves may be subject to damage -- and therefore be involved in cancer -- emerged from Pellman's previous research into aneuploidy. "We found that cancer cells generated from cells with micronuclei also have a great deal of chromosome breakage," Pellman explains. But researchers didn't know if this was a sign of connection or of coincidence.
Another clue came from a recently discovered phenomenon called "chromothripsis," in which one chromosome of a cancer cell shows massive amounts of breakage and rearrangement, while the remainder of the genome is largely intact. "That finding leapt off the page of these studies -- that such extensive damage could be limited to a single chromosome or single arm of a chromosome," Pellman says. "We wondered if the physical isolation of chromosomes in micronuclei could explain this kind of highly localized chromosome damage."
To find out, Karen Crasta, PhD, of Pellman's lab and the study's lead author, used a confocal microscope to observe dividing cells with micronuclei. She found that while micronuclei do form duplicate copies of their chromosomes, the process is bungled in two respects. First, it is inefficient: part of the chromosome is replicated and part isn't, leading to chromosome damage. Second, it is out of sync: the micronucleus keeps trying to replicate its chromosomes long after replication of the other chromosomes was completed. For cell division to be successful, every step of the process must occur in the proper order, at the proper time. In fact, when study co-author Regina Dagher directly analyzed the structure of the late-replicating chromosomes, she found them to be smashed to bits -- exactly what was predicted as the first step in chromothripsis.
The final piece of the puzzle came when Pellman's colleague Neil Ganem, PhD, examined what happens to these pulverized fragments, using an imaging trick that marked the chromosome in the micronucleus with its own color.
"It has been theorized that micronuclei are garbage disposals for chromosomes that the cell doesn't need anymore," Pellman comments. "If that were true, the smashed pieces would be discarded or digested, but we found that, a third of the time, they're donated to one of the daughter cells and therefore cold be incorporated into that cell's genome.
Pellman says that the findings suggest that, unexpectedly, whole chromosome aneuploidy might promote cancer in a very similar way to other kinds of genomic alterations. The key event may be mutations in oncogenes and tumor suppressors. This mechanism may also explain how cancer cells acquire more than one such mutation at a time.
"Although chromothripsis occurs in only a few percent of human cancers, our findings suggest that it might be an extreme instance of a kind of chromosome damage that could be much more common," says Pellman, who adds that accelerating this process in cancer cells, thus generating so many mutations that the cells die, may represent a possible strategy for new therapies against certain tumors.
News source:medicalxpress

Scientists replicate key evolutionary step in life on earth

News of science:  
Just how that happened is a question that has eluded evolutionary biologists.
Now scientists have replicated that key step in the laboratory using common Brewer's yeast, a single-celled organism.
The yeast "evolved" into multi-cellular clusters that work together cooperatively, reproduce and adapt to their environment--in essence, they became precursors to life on Earth as it is today.
The results are published in this week's issue of the journal Proceedings of the National Academy of Sciences (PNAS).
"The finding that the division-of-labor evolves so quickly and repeatedly in these 'snowflake' clusters is a big surprise," says George Gilchrist, acting deputy division director of the National Science Foundation's (NSF) Division of Environmental Biology, which funded the research.
"The first step toward multi-cellular complexity seems to be less of an evolutionary hurdle than theory would suggest," says Gilchrist. "This will stimulate a lot of important research questions."
It all started two years ago with a casual comment over coffee that bridging the famous multi-cellularity gap would be "just about the coolest thing we could do," recalled Will Ratcliff and Michael Travisano, scientists at the University of Minnesota (UMN) and authors of the PNAS paper.
Other authors of the paper are Ford Denison and Mark Borrello of UMN.
Then came the big surprise: it wasn't that difficult.
Using yeast cells, culture media and a centrifuge, it only took the biologists one experiment conducted over about 60 days.

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Multi-cellular 'snowflake' yeast images with a blue cell-wall stain and red dead-cell stain. Credit: Will Ratcliff and Mike Travisano

"I don't think anyone had ever tried it before," says Ratcliff. "There aren't many scientists doing experimental evolution, and they're trying to answer questions about evolution, not recreate it." The results have earned praise from evolutionary biologists around the world.
"To understand why the world is full of plants and animals, including humans, we need to know how one-celled organisms made the switch to living as a group, as multi-celled organisms," says Sam Scheiner, program director in NSF's Division of Environmental Biology.
"This study is the first to experimentally observe that transition," says Scheiner, "providing a look at an event that took place hundreds of millions of years ago."
In essence, here's how the experiments worked:
The scientists chose Brewer's yeast, or Saccharomyces cerevisiae, a species of yeast used since ancient times to make bread and beer because it is abundant in nature and grows easily.
They added it to nutrient-rich culture media and allowed the cells to grow for a day in test tubes.
Then they used a centrifuge to stratify the contents by weight.
As the mixture settled, cell clusters landed on the bottom of the tubes faster because they are heavier. The biologists removed the clusters, transferred them to fresh media, and agitated them again.

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First steps in the transition to multi-cellularity: 'snowflake' yeast with dead cells stained red. Credit: Will Ratcliff and Mike Travisano

Sixty cycles later, the clusters--now hundreds of cells--looked like spherical snowflakes. Analysis showed that the clusters were not just groups of random cells that adhered to each other, but related cells that remained attached following cell division.
That was significant because it meant that they were genetically similar, which promotes cooperation. When the clusters reached a critical size, some cells died off in a process known as apoptosis to allow offspring to separate.
The offspring reproduced only after they attained the size of their parents.

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Multi-cellular yeast individuals containing central dead cells, which promote reproduction. Credit: Will Ratcliff and Mike Travisano

"A cluster alone isn't multi-cellular," Ratcliff says. "But when cells in a cluster cooperate, make sacrifices for the common good, and adapt to change, that's an evolutionary transition to multi-cellularity." In order for multi-cellular organisms to form, most cells need to sacrifice their ability to reproduce, an altruistic action that favors the whole but not the individual, Ratcliff says.
For example, all cells in the human body are essentially a support system that allows sperm and eggs to pass DNA along to the next generation.
Thus multi-cellularity is by its nature very cooperative.
"Some of the best competitors in nature are those that engage in cooperation, and our experiment bears that out," says Travisano.
Evolutionary biologists have estimated that multi-cellularity evolved independently in about 25 groups.
Travisano and Ratcliff wonder why it didn't evolve more often since it's not that difficult to recreate in a lab.
Considering that trillions of one-celled organisms lived on Earth for millions of years, it seems like it should have, Ratcliff says.
That may be a question the biologists will answer in the future using the fossil record for thousands of generations of multi-cellular clusters, which are stored in a freezer in Travisano's lab.
Since the frozen samples contain multiple cell lines that independently became multi-cellular, the researchers can compare them to learn whether similar or different mechanisms and genes were responsible in each case, Travisano says.
The next steps will be to look at the role of multi-cellularity in cancer, aging and other critical areas of biology.
"Multi-cellular yeast is a valuable resource for investigating a wide variety of medically and biologically important topics," Travisano says.
"Cancer was recently described as a fossil from the origin of multi-cellularity, which can be directly investigated with the yeast system.
"Similarly the origins of aging, development and the evolution of complex morphologies are open to direct experimental investigation that would otherwise be difficult or impossible."
News source: physorg

 

Green cells are undergoing cell death, a cellular division-of-labor--fostering new life. Credit: Will Ratcliff and Mike Travisano

More than 500 million years ago, single-celled organisms on Earth's surface began forming multi-cellular clusters that ultimately became plants and animals.

 

Study finds how lysozyme protein in tears annihilates dangerous bacteria

News of science: 
A disease-fighting protein in our teardrops has been tethered to a tiny transistor, enabling UC Irvine scientists to discover exactly how it destroys dangerous bacteria. The research could prove critical to long-term work aimed at diagnosing cancers and other illnesses in their very early stages.
Ever since Nobel laureate Alexander Fleming found that human tears contain antiseptic proteins called lysozymes about a century ago, scientists have tried to solve the mystery of how they could relentlessly wipe out far larger bacteria. It turns out that lysozymes have jaws that latch on and chomp through rows of cell walls like someone hungrily devouring an ear of corn, according to findings that will be published Jan. 20 in the journal Science.
"Those jaws chew apart the walls of the bacteria that are trying to get into your eyes and infect them," said molecular biologist and chemistry professor Gregory Weiss, who co-led the project with associate professor of physics & astronomy Philip Collins.
The researchers decoded the protein's behavior by building one of the world's smallest transistors – 25 times smaller than similar circuitry in laptop computers or smartphones. Individual lysozymes were glued to the live wire, and its eating activities were monitored.
"Our circuits are molecule-sized microphones," Collins said. "It's just like a stethoscope listening to your heart, except we're listening to a single molecule of protein."
It took years for the UCI scientists to assemble the transistor and attach single-molecule teardrop proteins. The scientists hope the same novel technology can be used to detect cancerous molecules. It could take a decade to figure out, but would be well worth it, said Weiss, who lost his father to lung cancer.
"If we can detect single molecules associated with cancer, then that means we'd be able to detect it very, very early," Weiss said. "That would be very exciting, because we know that if we treat cancer early, it will be much more successful, patients will be cured much faster, and costs will be much less."
News source:physorg
 

Not by asteroid alone: Rethinking the Cretaceous mass extinction

News of science:At the end of the Cretaceous period some 65 million years ago, an asteroid slammed into Mexico’s Yucatan Peninsula, causing severe but selective extinction. While that is widely accepted, it has remained unclear exactly what the mechanisms were that caused extinction of ocean-dwelling organisms. Proposed explanations include global darkness due to blocking of sunlight with resulting interruption of photosynthesis at the base of the food chain, deadly radiation due to ozone destruction, global cooling or warming, and ocean acidification). Various widely-accepted hypotheses focus on a collapse of the primary and export productivity in the oceans – such as the so-called Strangelove Ocean or Living Ocean hypotheses, respectively – but do not account for the finding that deep-sea floor dwelling phytoplankton-dependent benthic foraminifera did not undergo significant extinction. Recently, however, research conducted at Universidad Zaragoza in Spain compared benthic foraminiferal records with benthic and bulk stable carbon isotope records. The scientists concluded that decreased productivity was moderate, regional, and insufficient to explain marine mass extinction, suggesting instead that a temporary period of increased surface ocean acidity may have been the primary cause of extinction of calcifying plankton and ammonites, with recovery of primary productivity possibly being as fast in the oceans as on land.
Researchers Laia Alegret at Universidad Zaragoza, Ellen Thomas at Yale University, and Kyger C Lohmann at the University of Michigan faced a range of issues in comparing benthic foraminiferal records with benthic and bulk stable carbon isotope records. “One of the main challenges is always to obtain sufficient benthic foraminiferal specimens for a statistically valid analysis,” says Thomas. “In the deep sea, there is no light, and so no photosynthesis. Therefore, almost all food must come from photosynthesis in the surface waters kilometers above – and only a very small percentage of the primary material, produced by unicellular algae, ever reaches the sea bottom.”
Put simply, deep-sea benthic foraminifera and other deep-sea organisms¹ live in a world where the limiting factor of life is food – because there is extremely little of it.² This implies that in samples from the deep-sea floor, microscopic shells of the organisms the team studied – foraminifera, a group of unicellular eukaryotes – are dramatically outnumbered by the shells of their relatives that live floating in the sunlit surface waters, and whose shells also fall to the sea floor. “We need to collect at least 300 specimens of the deep-sea dwellers per sample, which takes a lot of time sitting behind the microscope and hand-picking the bottom dwellers from the much more abundant surface dwellers,” Thomas explains to PhysOrg.com. “Then the very highly diverse assemblages need to be sorted out, and all specimens assigned to species.” Thomas also emphasizes that this is complicated by the fact that there is not true international agreement on the taxonomy of these species.
The team addressed these issues in a number of ways. “First,” agrees Alegret, “the consistency of our data set is unprecedented: The same authors used the same procedures and the same taxonomic concepts for all sites. Another challenge,” Alegret adds, “was finding microfossils in sediment that is not strongly affected by diagenesis – the high pressure and temperatures that take place during the formation of hard rocks from initially soft clay and ooze, which may strongly affect isotopic results. Material in sediment from scientific ocean drilling sites,” she continues, “is commonly less affected by diagenesis than samples obtained from rocks in quarries and outcrops on land. This gave us good preservation of the calcium carbonate, ensuring accuracy of our isotope results.”
Thomas notes that the team argues that a collapse of primary productivity by the unicellular algae in the surface waters as proposed in the Strangelove Ocean hypothesis, or continued productivity by such algae but a lack of transport of these algae into the deep bottom waters (also called a collapse of the biological pump) as proposed by the Living Ocean model, would both have resulted in an interruption of food supply to the bottom dwellers for hundreds of thousands of years. “Such an interruption of food supply should have had a serious influence on the bottom dwellers, which in the present oceans react even to changes in the seasonality of food supply. However, we didn’t see that. Rather, the bottom dwellers did not go extinct, indicating that they must have had access to food.”
In fact, Alegret notes, in some regions – for example, the Pacific Ocean – there they found an increase in the food supplied to the sea floor – which, she points out, “is incompatible with both the Strangelove Ocean and Living Ocean hypotheses.”
The scientists point out that their findings may impact other areas of research, from paleobiology to evaluating the effects of increasing atmospheric levels of carbon dioxide. “In many fields of paleontology it has been accepted that the main cause of such extinction was the collapse of primary productivity,” Thomas notes. “If that is not the case, one needs to look at other factors. If we’re correct in our speculation that a rapid pulse of oceanic acidification can have very severe effects on ocean life, then we need to take that into account when evaluating the potential effects of the very rapid anthropogenic ocean acidification, caused by a different type of acid – specifically, due to high carbon dioxide levels – on ocean life in the near future.”
The team is already looking forward to extending their research. However, Thomas cautions, what they’d like to do and what they’ll be able to do depends at least in part on funding. “We’re rather far along with a high resolution analysis of foraminifera and stable isotopes from a site close to one of our studied sites, but in shallower waters.” Once they have these data collected, they can better compare what happened at different depths in the water column in an expansion of their work at different geographic locations.
“It would be very exciting,” Thomas envisions, “to test whether we can indeed find direct and quantitative evidence, rather than evidence from extinction patterns of calcifying organisms, for the pH values of the surface waters of the oceans – for example, by trying to apply proxies for oceanic pH and carbonate saturation, such as measuring boron isotopes and/or boron/calcium values in the shells of planktic, or surface-dwelling, and benthic foraminifera across the extinction interval. This is not easy to do,” she points out, “because the planktic – also termed planktonic – foraminifera were so severely affected by the extinction – but it may be possible with the modern possibility to analyze very small amounts of calcite.”
“If we want to predict the future effects of the present acidification of the oceans,” Alegret concludes, “we should investigate and understand past acidification events by, for example, comparing the very rapid acidification event triggered by the end-Cretaceous impact 65 million years ago with the much slower acidification during the extreme warming event which occurred 55 million years ago at the end of the Paleocene and caused severe extinction of benthic foraminifera.”
News source:physorg

Telescope takes a fresh look into a nebula's golden eye

News of science:

J. Emerson / CASU / VISTA / ESO

The European Southern Observatory's Visible and Infrared Survey Telescope for Astronomy, or VISTA, captured this unusual view of the Helix Nebula, a planetary nebula located 700 light-years away. The colored picture was created from images taken through three infrared filters. While bringing to light a rich background of stars and galaxies, the telescope's infrared vision also reveals strands of cold nebular gas that are mostly obscured in visible images of the Helix.

A nearby planetary nebula shines like a huge golden eye in a new photo snapped by a telescope in Chile.

The image shows the Helix Nebula, which lies about 700 light-years from Earth in the constellation Aquarius, the Water Bearer. The picture was taken in infrared light by the European Southern Observatory's VISTA telescope, one of the instruments at ESO's Paranal Observatory.
The Helix Nebula is a planetary nebula, a strange object that forms when a star like our sun exhausts its hydrogen fuel. The star's outer layers expand and cool, creating a huge envelope of dust and gas. Radiation flowing from the dying star ionizes this envelope, causing it to glow.
Despite their name, planetary nebulas have nothing to do with planets. Rather, the term refers to their superficial resemblance to giant planets, when observed through early telescopes. [See the new Helix nebula photos and video]
The dying star at the heart of the Helix Nebula is evolving to become a white dwarf, a shrunken, super-dense object that can pack a sun's worth of material into a sphere the size of Earth. The star is visible as a tiny blue dot at the center of the picture, researchers said.
The Helix Nebula is a complex object composed of dust, ionized material and molecular gas, arrayed in an intricate, flowerlike pattern.
The main ring of the Helix is about 2 light-years across, roughly equivalent to half the distance between our sun and its closest star. However, wispy material from the nebula spreads out at least 4 light-years into space from the central star, researchers said.

These thin clouds of molecular gas are difficult to see in visible light, but Vista's infrared detectors can pick them out, and they show up in the new image as a dark red haze.
Vista's keen eye also reveals fine structure in the planetary nebula’s rings, showing how cooler molecular gas is organized. The material clumps into filaments that radiate out from the center.
While they may look tiny, these strands of molecular hydrogen — known as cometary knots — are each about the size of our solar system. The molecules that compose them can survive the powerful radiation emanating from the dying star precisely because they clump into these knots, which in turn are shielded by dust and molecular gas.
It is currently unclear how the cometary knots may have formed, researchers said.
The new Vista image also shows a wide array of stars and galaxies in the background, farther away than the Helix Nebula.
News source:msnbc.msn