Monday, March 26, 2012

Carbon dioxide breaking down marine ecosystems

VANCOUVER — If carbon dioxide emissions don’t begin to decline soon, the complex fabric of marine ecosystems will begin fraying — and eventually unravel completely, two new studies conclude.
The diversity of ocean species thins and any survivors’ health declines as the pH of ocean water falls in response to rising carbon dioxide levels, scientists from England and Florida reported February 18 at the annual meeting of the American Association for the Advancement of Science. What’s more, affected species aren’t restricted to those with shells and calcified support structures — features particularly vulnerable to erosion by corrosive seawater.
Jason Hall-Spencer of the University of Plymouth, England, and his colleagues have been collecting data from marine sites off Italy, Baja California and Papua New Guinea, where high concentrations of carbon dioxide percolate out of the seabed from volcanic activity below. Directly above these CO2 seeps, pH plummets to at least 7.8, a value that is expected to occur widely by 2100 and that is substantially lower than the normal level for the area, 8.1. These sites offer a preview of what may happen to seafloor ecosystems as CO2 levels continue to rise, causing ocean water pH to drop.
Compared with nearby normal-pH sites, species richness in low-pH zones was diminished by 30 percent, Hall-Spencer reported. “Coral and some algae are gone. And the sea urchins are gone,” he said. Fish may be present, but unlike in areas with a normal pH, they won’t deposit their eggs there.
Although seagrasses appear to survive just fine in the low-pH seawater, close inspection showed that fish had nibbled the fronds, Hall-Spencer found. He identified one likely explanation: At low pH, these grasses no longer produced the phenolic defense compounds that typically deter munching by grazing animals.
His team also transplanted a host of healthy marine species to sites along a gradient of pH values leading up to an Italian seep, then monitored the immigrants’ health for a year.
Even shelled animals initially survived from fall to spring, in some cases bumping up their calcification in an attempt to cope with the corrosive waters. The surprise, Hall-Spencer notes: When peak temperatures arrived in August, many transplanted corals and mollusks died “due to the double whammy effect of high CO2 and high temperature.”
In lab experiments, Chris Langdon of the University of Miami Rosenstiel School of Marine and Atmospheric Science and colleagues raised coral larvae at pH values representing the South Pacific today and at levels expected in 50 and 100 years. Compared with newly spawned larvae at normal pH, the metabolism of those raised in the lowest pH environment dropped 65 percent, Langdon reported.
“You can think of this” — the lowered metabolism — “as a ball and chain attached to the leg of every coral larva,” Langdon says. “It’s not killing it outright, but each will have to go through life dragging this ball and chain behind.” Langdon also found that the larvae’s ability to make energy from nutrients in the water also suffered in the reduced pH. “So it’s like they’re starving at the same time,” he said.
Finally, there was a 60 percent decline in the number of larvae that could settle out onto a simulated reef surface, Langdon reported. One reason may have to do with the effects of acidification on turf algae in their environment. These algae made less of two key pigments. Ordinarily, the pigments “call out to the larvae, saying this is a nice place to settle,” he explains.
In Papua New Guinea, Langdon found evidence that the same thing appears to be happening in the wild at CO2 seeps with comparable pH values.
Other scientists reported at the meeting that at some sites, such as along the West Coast of the United States, seawater regionally — and regularly — falls to a pH of 7.5 or lower owing to natural factors other than CO2 seeps. Such new data may explain the occasional catastrophic wipeouts of young farmed shellfish in recent years, notes Gretchen Hofmann of the University of California, Santa Barbara.

Cell phone research suggests fetal risk

Round-the-clock cell phone radiation may harm growing brains, a mouse study suggests. Mice exposed to an active phone for the duration of a pregnancy gave birth to pups that displayed long-lasting behavioral and brain abnormalities, researchers write March 15 in Scientific Reports.
Although the results indicate that chronic exposure to cell phone radiation can disrupt the fetal brain in mice, it’s unclear whether the same holds true for people. “The paper is an interesting paper. There are no two ways around that,” says Nora Volkow, director of the National Institute on Drug Abuse in Bethesda, Md., who has studied the effects of cell phone radiation. “The issue is, ultimately, what is the significance to humans?”
In the study, reproductive endocrinologist Hugh Taylor of Yale School of Medicine and colleagues rigged up bare-bones cell phones (not smart phones) to pregnant mice’s cages. Half the phones were actively receiving a call on mute for the entirety of the mice’s pregnancies, which last about 17 days. The other phones were inactive.
On average, offspring from the mothers exposed to cell phone radiation performed worse on a memory test, moved around more, and were less anxious than mice who were not exposed to cell phone radiation. Nerve cell signaling in the prefrontal cortex — a brain region that, in humans, sits behind the forehead and has been implicated in many mental disorders — was also dampened in exposed mice.
In the report, Taylor and his colleagues suggest that these behavioral and brain deficits are similar to those seen in people with attention-deficit/hyperactivity disorder, and speculate that increased cell phone use could explain an increase in ADHD in children.
Other scientists disagree. “To blame the increase in ADHD on mobile phones, that is premature,” says cognitive neuroscientist and ADHD researcher Katya Rubia of King’s College London, who says that such a claim is alarmist and unjustified. The behavioral deficits of the mice are very different from the behavioral symptoms seen in people with ADHD, she says.
Mouse fetuses in the experiment were between 4.5 and 22.3 centimeters from the phone at all times — creating a different exposure than what a human fetus would receive. And Volkow notes that human fetuses have more protective amniotic fluid around them. “The exposures were too high and too intense to be translated to humans,” she says.
So far, other research has hinted at a possible link between pregnant women who used cell phones frequently and behavioral problems in their children. Two studies, led by epidemiologist Hozefa Divan, who conducted the research at UCLA and at the University of Southern California in Los Angeles, found such an association. But more studies are needed, he says. “There’s still a lack of really solid evidence one way or the other.”
In the meantime, the researchers agree that pregnant women should avoid carrying a cell phone near the abdomen. “I don’t want to sensationalize this or cause panic, but I think it’s worth being cautious,” Taylor says.

Growth-promoting antibiotics: On the way out?

In 1950, Science News ran a story showing for the first time that a potent antibiotic could do more than knock out disease. New animal experiments, we reported, “cast the antibiotic in a spectacular new role” as a livestock growth promoter. Lacing the food of hogs with trace quantities of this drug increased meat yields by up to 50 percent, scientists at Lederle Laboratories had reported at a research conference. Sixty-two years later — to the day — a federal judge has now ordered the Food and Drug Administration to resume efforts toward outlawing this nonmedical use of antibiotics.
The 1950s were rife with ebullient prognostications. And our reporter back then had found the prospect of boosting meat production with harmless quantifies of a drug exciting. Our story proclaimed that the discovery “may hold enormous long-range significance for the survival of the human race in a world of dwindling resources and expanding populations.”
But it turned out that here, as in so many instances, there’s no free lunch.
Feeding animals trace quantities of an antibiotic didn’t harm them. In fact, it launched the widespread and largely indiscriminate use of these life-saving drugs for nonmedical purposes. As germs encountered subtherapeutic doses of these medicines again and again, both in animals and the environment, bacteria evolved a resistance to them.
Before long, that resistance began emerging in humans who became infected with the same germs, or close relatives to them. The result: As in the 1930s, people were again facing life threatening illness from germs that antibiotic wonder drugs had been developed to eradicate.
FDA knew about this, of course, notes U.S. Magistrate Judge Theodore Katz in his new ruling. Thirty-five years ago, he points out, “FDA issued notices announcing its intent to withdraw approval of the use of certain antibiotics in Iivestock for the purposes of growth promotion and feed efficiency.” At that time, FDA acknowledged that nonmedical use of penicillin and tetracycline-type drugs — and the drug resistance they were spawning — threatened human health.
By law, that 1977 ruling should have set in motion a procedure of hearings that would give drug manufacturers a chance to rebut the FDA assessment. If the drug makers didn’t challenge the assessment or prove that FDA had gotten it wrong, growth promoting use of the drugs would have to end.
But those hearings never took place, which has given livestock growers a 35-year extension of the drugs' use.
Enter the Natural Resources Defense Council. Last year, its litigators filed a lawsuit against FDA on behalf of the Center for Science in the Public Interest, Food Animal Concerns Trust, Public Citizen, and the Union of Concerned Scientists. These public-interest groups charged that FDA dropped the ball and the public was suffering. They asked the court to make FDA resume its procedural case against antibiotics in livestock feed.
For its part, FDA argued that it was in the process of working with drug manufacturers to encourage a voluntary phaseout of growth-promoting applications of penicillin and tetracycline antibiotics. So the agency argued it no longer needed to formally outlaw these uses.
Not true, argues Judge Katz in his March 22 opinion. The law is the law. Once FDA made a preliminary determination that human health was imperiled by nonmedical antibiotic uses, the process must progress toward a formal withdrawal of legal approval for this application. As long as the initial science has not been proven wrong in the interim, the agency is obligated to complete the action it started — even after 35 years.
Indeed, the judge observes, over the intervening decades “scientific evidence of the risks to human health from the widespread use of antibiotics in livestock has grown.” Those health concerns — and accumulating libraries of data — also point to risks for antibiotics that extend well beyond the penicillin and tetracyclines covered in FDA’s 1977 assessment. In fact, two citizen petitions asked FDA to end growth-promoting uses for additional antibiotics.

Last year, FDA threw out the petitions, arguing they were moot now that the agency was working with drug manufacturers towards some sort of voluntary phasedown or phaseout.

Arguing that voluntary guidelines will not satisfy these claims either, “We’re challenging the denials of those petitions,” says Avinash Kar, one of the NRDC attorneys involved. “So that part of the case is still being litigated,” he says, “and will probably result at some point in a court hearing.”
For now, Judge Katz has merely instructed FDA to go ahead and hold hearings on the fate of penicillin and tetracycline. How soon the agency must act has not yet been spelled out, Kar says: “Further court proceedings will decide the timeline. And, of course, it’s possible that FDA might appeal.”

Fatty diet leads to fat-loving brain cells

Cheeseburgers pack on the pounds, but in mice a high-fat diet also packs on new nerve cells in the brain. More brain cells may seem like a good thing, but these newly sprouted cells appear to trigger weight gain in the animals, a new study finds.
The results offer insight into how the brain controls weight. If the same thing happens in humans, these nerve cells may be a target for anti-obesity treatments.
“This kind of work will definitely inform how we think about the underlying factors that relate to obesity,” says endocrinologist Jeffrey Flier of Harvard Medical School in Boston. There’s increasing interest, he says, in how long-term changes in brain circuitry — like new nerve cell production — affect eating and hunger. “That is going to be a very interesting frontier.”
With some key exceptions, most regions in the adult brain don’t make new nerve cells. But in a small sliver of brain tissue called the median eminence, new nerve cells are born throughout life, neuroscientist Seth Blackshaw of Johns Hopkins University School of Medicine and colleagues report online March 25 in Nature Neuroscience. The median eminence is part of the brain’s metabolism hub known as the hypothalamus.
And one signal to step up production in the median eminence, the team found, is a diet high in fat.
In the study, mice that ate the rodent version of a steady stream of Big Macs gained weight. This unhealthy diet also kicked nerve cell production into high gear, the scientists found. After eating a fatty diet for several weeks, adult mice pumped out about four times as many new nerve cells in the median eminence as mice that ate regular chow.
To see whether these newborn nerve cells were up to no good, Blackshaw and his team shut down production with a carefully targeted laser. Even while continuing to gorge on a high-fat diet, these mice started moving around more and didn’t gain as much weight as mice on a high-fat diet that could still make the new nerve cells. Take away the steady stream of new nerve cells, and the pounds didn’t pile on as fast.
The newborn cells’ parents turn out to be a mysterious kind of brain cell that resides in the median eminence. Both mice and people have these cells, called tanycytes, but no one knew what their role was. “There’s been a lot of speculation about what their function may be,” says Blackshaw.
The scientists don’t yet know how these newborn nerve cells can influence metabolism. Other studies, including those by Flier, have found that a high-fat diet actually reduces nerve cell turnover in other parts of the hypothalamus.
Blackshaw cautions that it’s too soon to say whether a similar thing could be going on in people. “This is the very first step in trying to understand this process,” he says. “We’re a long way from realizing whether this is relevant to human obesity.”

Solar radius measured precisely

A group of scientists from Hawaii, Brazil and California has measured the diameter of the Sun with unprecedented accuracy by using a spacecraft to time the transits of the planet Mercury across the face of the Sun in 2003 and 2006.
They measured the Sun's radius as 696,342 km (432,687 miles) with an uncertainty of only 65 km. This was achieved by using the solar telescope aboard a NASA satellite, thereby bypassing the blurring caused by Earth's atmosphere that occurs when observations are made from the ground, notes a University of Hawaii Institute for Astronomy Press Release.
The measurements of the Sun's size were made by University of Hawaii Institute for Astronomy scientists. They used the Michelson Doppler Imager (MDI) aboard NASA's Solar and Heliospheric Observatory (SOHO) to make the measurements.
Transits of Mercury occur 12-13 times per century, so observations like this allow us to refine our understanding of the Sun's inner structure. The team is preparing to observe the transit of Venus across the Sun on June 5. They expect these observations will improve the accuracy of their solar size measurement even further.

Stem cell science is already saving lives

It is mid-morning in the delivery suite at King's College hospital in London, and midwife Terie Duffy is cooing over the contents of a stainless-steel bowl. “Isn't it beautiful?” she says. “This is what makes my job worthwhile ... the opportunity to give the chance of life.” But the object of her attention is not a baby. It is a placenta, which was, until about five minutes ago, attached to 4.1kg (9lb) Princess Gracie, who is crying lustily in the birthing room next door with her mum Charlotte Cribben and dad Andre Kum. “It has done its job for Princess Gracie,” explains Duffy. “And now the precious stem cells it contains could cure another child or adult of leukaemia or another blood disease.” Hirasine Sengomona, one of the cord collectors at King's, lifts the placenta to eye-level and pulls the attached umbilical cord downward so the blood runs down it, before piercing it with a needle. Within seconds, the attached plastic bag is filling with blood. “The cells we're collecting are magic cells, miraculous cells,” says Duffy. “They're the blueprint for all the different cells in the blood — so for someone whose own bone marrow isn't working properly, they can be a real lifeline.” Sengomona weighs the bag. At 102g, it is not enough for a transplant, says Duffy, but enormously useful to haematologists doing research into stem cells and their use. Duffy has been running the cord blood collection programme at King's — one of the most advanced schemes of its kind in this country — for the past five years. “For most parents, whether to donate or not is a complete no-brainer,” she says.
One recipient
Mariana Lopes and Simon Brooks, whose son Joseph was born the previous day at King's, agree. “When it was explained to us that this is a waste product, and that giving it would not affect us or the baby in any way, we didn't hesitate,” says Brooks. “To think that Joseph's cord blood, which will be frozen in the stem blood bank, could help someone in the future is really good.” So far there have been around 2,500 cord blood donations from King's; but it was only a few weeks ago that the first transplant from any of those donations took place, after the Anthony Nolan register, which administers a scheme to which King's belongs, matched a donation with an adult male with blood cancer. He is apparently doing well. “That's the most fabulous news,” says Duffy. “We hope there will now be many more recipients of cord blood from King's.” The fact that the King's programme has had only one recipient so far is largely because the science is still in its infancy.
Treating more diseases
“It's early days,” says Antonio Pagliuca, professor of stem cell transplantation at King's. “The cord blood bank is already saving lives, but research is ongoing and it's very likely that in the future, more ways of using cord blood will become clear, and it may be possible to treat more diseases.” Currently, most of the recipients of cord blood — as with those who receive bone marrow transplants from family members — have leukaemia, lymphoma or other blood diseases. There are two cord blood banks in Britain, one run by the Anthony Nolan register and another by the tax-funded National Health Service (NHS) Blood and Transplant Service. They harvest cord blood from a handful of hospitals — the NHS bank collects from maternity hospitals in and around London, while Anthony Nolan collects from hospitals in the Midlands as well as in London. Both banks hope to expand further, aided by £4m split across both from the Department of Health last year.
Around 2,500 donations are banked with the Anthony Nolan scheme, and another 18,000 with the NHS cord blood bank; the banks' targets are 15,000 and 35,000 respectively, which, says Guy Parkes of Anthony Nolan, should ensure that most patients who need a donation of blood stem cells should be able to find a match, using either the register of adults willing to donate, or the cord blood bank.
The schemes, he says, are entirely separate from private cord blood banks, which charge parents to bank their baby's cord blood for potential future personal use ; and although the administrators of the public banks take a neutral view on the usefulness or otherwise of private cord blood banks (some of which charge £1,500), Parkes does point out that, while plenty of cord bloods have been banked privately worldwide, there have been very few cases of them being successfully used.
Recipients of cord blood from public banks, on the other hand, are on the increase. Three-year-old Austin Clover, who was diagnosed with a pre-leukaemic condition at eight months old, had cord blood from the Czech blood bank (sourced by Anthony Nolan) in October 2010. He spent months in isolation until the graft had taken, but is now, says his mother Kerry Tuffin, living a normal life. “He recently started at nursery and he's doing really well,” she says. “I'll never know the Czech mother who donated her baby's blood, but I wish I could tell her what a difference it has made to Austin's life, and to ours.” — © Guardian Newspapers Limited, 2012

Circadian rhythms linked to sudden cardiac death

A fundamental discovery reported today (February 23) in Nature uncovers the first molecular evidence linking the body's natural circadian rhythms to sudden cardiac death.
Ventricular arrhythmias, or abnormal heart rhythms, are the most common cause of sudden cardiac death: the primary cause of death from heart disease. They occur most frequently in the morning waking hours, followed by a smaller peak in the evening hours. While scientists have observed this tendency for many years, prior to this breakthrough, the molecular basis for these daily patterns was unknown. 

Thursday, March 15, 2012

Sleep Makes Your Memories Stronger, and Helps With Creativity

As humans, we spend about a third of our lives asleep. So there must be a point to it, right? Scientists have found that sleep helps consolidate memories, fixing them in the brain so we can retrieve them later. Now, new research is showing that sleep also seems to reorganize memories, picking out the emotional details and reconfiguring the memories to help you produce new and creative ideas, according to the authors of an article in Current Directions in Psychological Science.
         
"Sleep is making memories stronger," says Jessica D. Payne of the University of Notre Dame, who co-wrote the review with Elizabeth A. Kensinger of Boston College. "It also seems to be doing something which I think is so much more interesting, and that is reorganizing and restructuring memories."
Payne and Kensinger study what happens to memories during sleep, and they have found that a person tends to hang on to the most emotional part of a memory. For example, if someone is shown a scene with an emotional object, such as a wrecked car, in the foreground, they're more likely to remember the emotional object than, say, the palm trees in the background -- particularly if they're tested after a night of sleep. They have also measured brain activity during sleep and found that regions of the brain involved with emotion and memory consolidation are active.
"In our fast-paced society, one of the first things to go is our sleep," Payne says. "I think that's based on a profound misunderstanding that the sleeping brain isn't doing anything." The brain is busy. It's not just consolidating memories, it's organizing them and picking out the most salient information. She thinks this is what makes it possible for people to come up with creative, new ideas.
Payne has taken the research to heart. "I give myself an eight-hour sleep opportunity every night. I never used to do that -- until I started seeing my data," she says. People who say they'll sleep when they're dead are sacrificing their ability to have good thoughts now, she says. "We can get away with less sleep, but it has a profound effect on our cognitive abilities."

'Mind-Reading' Experiment Highlights How Brain Records Memories

It may be possible to "read" a person's memories just by looking at brain activity, according to research carried out by Wellcome Trust scientists. In a study published in the journal Current Biology , they show that our memories are recorded in regular patterns, a finding which challenges current scientific thinking.
     
Demis Hassabis and Professor Eleanor Maguire at the Wellcome Trust Centre for Neuroimaging at UCL (University College London) have previously studied the role of a small area of the brain known as the hippocampus which is crucial for navigation, memory recall and imagining future events. Now, the researchers have shown how the hippocampus records memory.
When we move around, nerve cells (neurons) known as "place cells", which are located in the hippocampus, activate to tell us where we are. Hassabis, Maguire and colleagues used an fMRI scanner, which measures changes in blood flow within the brain, to examine the activity of these places cells as a volunteer navigated around a virtual reality environment. The data were then analysed by a computer algorithm developed by Demis Hassabis.
"We asked whether we could see any interesting patterns in the neural activity that could tell us what the participants were thinking, or in this case where they were," explains Professor Maguire, a Wellcome Trust Senior Research Fellow. "Surprisingly, just by looking at the brain data we could predict exactly where they were in the virtual reality environment. In other words, we could 'read' their spatial memories."
Earlier studies in rats have shown that spatial memories – how we remember where we are – are recorded in the hippocampus. However, these animal studies, which measured activity at the level of individual or dozens of neurons at most, implied that there was no structure to the way that these memories are recorded. Hassabis and Maguire's work appears to overturn this school of thought.
"fMRI scanners enable us to see the bigger picture of what is happening in people's brains," she says. " By looking at activity over tens of thousands of neurons, we can see that there must be a functional structure – a pattern – to how these memories are encoded. Otherwise, our experiment simply would not have been possible to do."
Professor Maguire believes that this research opens up a range of possibilities of seeing how actual memories are encoded across the neurons, looking beyond spatial memories to more enriched memories of the past or visualisations of the future.
"Understanding how we as humans record our memories is critical to helping us learn how information is processed in the hippocampus and how our memories are eroded by diseases such as Alzheimer's," added Demis Hassabis.
"It's also a small step towards the idea of mind reading, because just by looking at neural activity, we are able to say what someone is thinking."
Professor Maguire led a study a number of years ago which examined the brains of London taxi drivers, who spend years learning "The Knowledge" (the maze of London streets). She showed that in these cabbies, an area to the rear of the hippocampus was enlarged, suggesting that this was the area involved in learning location and direction. In the new study, Hassabis, Maguire and colleagues found that the patterns relating to spatial memory were located in this same area, suggesting that the rear of the hippocampus plays a key role in representing the layout of spatial environments.

How Salmonella Avoids the Body's Immune Response

UC Irvine researchers have discovered how salmonella, a bacterium found in contaminated raw foods that causes major gastrointestinal distress in humans, thrives in the digestive tract despite the immune system's best efforts to destroy it.
       
Their findings help explain why salmonella is difficult to eradicate and point to new approaches for possible treatments. Most people infected with salmonella suffer from diarrhea, fever and abdominal cramps for up to seven days before the infection resolves.
Lead researcher Manuela Raffatellu, a UCI assistant professor of microbiology & molecular genetics, and colleagues identified a novel molecular mechanism that allows salmonella to survive. Results of their study appear in the March issue of Cell Host & Microbe.
Pathogens like salmonella flourish and cause disease in humans through a process by which they acquire metal ions, such as zinc, from the body. One of the body's key immune responses is to flood the infected area with antimicrobial proteins that include calprotectin, which removes zinc. Without enough of this vital element, most pathogens eventually die.
Raffatellu's team found, however, that salmonellae overcome this immune response by expressing specialized transporter proteins that enable the bacteria to acquire zinc in spite of calprotectin reducing the amount available in the digestive tract. This distinctive mechanism lets salmonellae continue proliferating.
At the same time, calprotectin inadvertently promotes salmonella growth by killing the microbes that normally reside within the intestines and help the immune system battle pathogenic bacteria.
"We're beginning to learn more about the mechanisms that allow pathogens like salmonella to evade our natural defenses and make us sick," Raffatellu said. "In light of this, if we can devise therapies that block the acquisition of zinc and other metals by salmonella specifically, we can fight this infection."
Additionally, she said, the new findings may have relevance for other illnesses, such as inflammatory bowel disease and colon cancer, in which high levels of calprotectin are detected.
Also contributing to the study, which was supported by grants from the National Institutes of Health, were Janet Z. Liu, Stefan Jellbauer, Adam Poe, Vivian Ton, Michele Pesciaroli, Martin Hosking, Robert A. Edwards and Thomas E. Lane of UCI; Thomas Kehl-Fie, Nicole A. Restrepo, Walter J. Chazin and Eric P. Skaar of Vanderbilt University; Andrea Battistoni of the University of Rome; Thomas Vogl and Johannes Roth of the University of Munster, Germany; and Paolo Pasquali of the Superior Health Institute in Rome.

Corn Insecticide Linked to Great Die-Off of Beneficial Honeybees

New research has linked springtime die-offs of honeybees critical for pollinating food crops -- part of the mysterious malady called colony collapse disorder -- with technology for planting corn coated with insecticides
  
The study, published in ACS' journal Environmental Science & Technology, appears on the eve of spring planting seasons in some parts of Europe where farmers use the technology and widespread deaths of honeybees have occurred in the past.
In the study, Andrea Tapparo and colleagues explain that seeds coated with so-called neonicotinoid insecticides went into wide use in Europe in the late 1990s. The insecticides are among the most widely used in the world, popular because they kill insects by paralyzing nerves but have lower toxicity for other animals. Almost immediately, beekeepers observed large die-offs of bees that seemed to coincide with mid-March to May corn planting. Scientists thought this might be due to particles of insecticide made airborne by the pneumatic drilling machines used for planting. These machines forcefully suck seeds in and expel a burst of air containing high concentrations of particles of the insecticide coating. In an effort to make the pneumatic drilling method safer, the scientists tested different types of insecticide coatings and seeding methods.
They found, however, that all of the variations in seed coatings and planting methods killed honeybees that flew through the emission cloud of the seeding machine. One machine modified with a deflector to send the insecticide-laced air downwards still caused the death of more than 200 bees foraging in the field. The authors suggest that future work on this problem should focus on a way to prevent the seeds from fragmenting inside the pneumatic drilling machines.
The authors acknowledge funding from the University of Padova and the Ministero delle Politiche Agricole Alimentari e Forestali, Italy.

Tuesday, March 6, 2012

Young Stars Exhibit 'Growing Pains' in Space


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Astronomers using powerful space telescopes have spotted a number of young stars in the Orion nebula changing right before their eyes. The developing stars are rapidly heating up and cooling down, illustrating the turbulent process of reaching full stellar adulthood. Brightness varied by more than 20 percent over just a few weeks.Astronomers using a European space telescope say they've seen changes in young stars in the Orion nebula suggesting a turbulent journey to stellar adulthood.
Data from the European Space Agency's Herschel Space Observatory, combined with observations from NASA's Spitzer Space Telescope, indicate stars strung across the telescope images are rapidly heating up and cooling down, a NASA release said Wednesday.
In an image of a portion of the Orion nebula, the telescopes' infrared vision reveals a number of embryonic stars, hidden in gas and dust clouds, at the very earliest stages of their evolution.
As clumps of this gas and dust come together, they form a warm glob of material that in several hundred thousand years will gather enough material to trigger nuclear fusion at their cores and blaze into stardom, astronomers said.
Astronomers noticed several of the young stars varied in their brightness by more than 20 percent over just a few weeks.
This puzzled the astronomers, who said cool Relevant Products/Services material emitting the infrared light must be far from the hot center Relevant Products/Services of the young star, likely in the outer disk Relevant Products/Services or surrounding gas envelope, and should take years or centuries to spiral closer in to the growing starlet, rather than mere weeks.
"Herschel's exquisite sensitivity opens up new possibilities for astronomers to study star formation, and we are very excited to have witnessed short-term variability in Orion protostars," said Nicolas Billot, an astronomer at the Institut de Radioastronomie Millimetrique in Grenada, Spain.
"Follow-up observations with Herschel will help us identify the physical processes responsible for the variability."

Poor Sleep May Lead to Increased Disease Risk, Death

 A lack of sleep can be downright dangerous, scientists say. A new study says there is increased inflammation in poor sleepers, and that inflammation is a marker associated with poor health and death. The study says poor sleepers have more depressive symptoms, more loneliness and more global perceived stress relative to good sleepers.

A U.S. study found stress led to significantly larger increases in a marker of inflammation in poor sleepers compared to good sleepers, researchers said.

Kathi L. Heffner, assistant professor of psychiatry at the University of Rochester Medical Center in New York, said inflammation is a marker associated with poor health outcomes and death.

"This study offers more evidence that better sleep not only can improve overall well-being but also may help prevent poor physiological and psychological outcomes associated with inflammation," Heffner said in a statement.

The study involved 45 women and 38 men with an average age of 61. The participants were evaluated for cognitive status and each participant completed a self-report of sleep quality, perceived stress, loneliness and medication use.

The participants were in good physical health, but 27 percent were categorized as poor sleepers.

On the day of the study, the participants were given a series of tests of verbal and working memory Relevant Products/Services, a battery of questions that served as the stressor. The blood was studied for levels of interleukin-6 a protein primarily produced at sites of inflammation.

The study published in the American Journal of Geriatric Psychiatry found poor sleepers reported more depressive symptoms, more loneliness and more global perceived stress relative to good sleepers. They also had as much as four times the level of interleukin-6, which increases the risk for illness and death in older adults, the study said.

Soft Drinks May Contain Carcinogen

 Can drinking soda cause cancer? A report from the Center for Science in the Public Interest says popular sodas contain high levels of a chemical that's used to give a caramel coloring, and that chemical could raise a soda-drinkers' cancer risk. A Coca-Cola spokesman disputed the health concerns raised by CSPI, saying the ingredients are safe.

Chemical analyses found Coca-Cola, Pepsi, Diet Coke and Diet Pepsi contain high levels of a known animal carcinogen, a U.S. food advocacy group said.
Michael F. Jacobson, executive director of the Center for Science in the Public Interest, said the group collected samples of Coca-Cola, Pepsi, Diet Coke, Diet Pepsi, Dr Pepper, Diet Dr Pepper and Whole Foods 365 Cola from Washington-area stores.
The analysis found Pepsi's products had 145 to 153 micrograms of 4-methylimidazole in two 12-ounce cans. Regular Coca-Cola had 142 micrograms per 12 ounces in one sample and 146 micrograms in another. Diet Coke had 103 micrograms per 12 ounces in one sample and 113 micrograms in another. In California, levels of 29-microgram of 4-methylimidazole and above in a food serving or beverage may be required have a warning notice, Jacobson said.
The carcinogen forms when ammonia or ammonia and sulfites are used to manufacture the "caramel coloring" that gives those sodas their distinctive brown colors, Jacobson said.
"Coke and Pepsi, with the acquiescence of the U.S. Food and Drug Administration, are needlessly exposing millions of Americans to a chemical that causes cancer," Jacobson said in a statement. "The coloring is completely cosmetic, adding nothing to the flavor of the product. If companies can make brown food coloring that is carcinogen-free, the industry should use that. And industry seems to be moving in that direction. Otherwise, the FDA needs to protect consumers from this risk by banning the coloring."
Pepsi told CSPI it switched to a coloring in California that contains much less 4-methylimidazole and plans to do the same in the rest of the country.
A Coca-Cola spokesman disputed the health concerns raised by CSPI.
"Unlike CSPI, the Coca-Cola Co. deals in hard facts," company spokesman Ben Sheidler said. "Fact: The body of science about 4-MEI in foods or beverages does not support the erroneous allegations that CSPI would like the public to believe. The 4-MEI levels in our products pose no health or safety risks. Outside of California, no regulatory agency concerned with protecting the public's health has stated that 4-MEI is a human carcinogen.
"The caramel color in all of our ingredients has been, is and always will be safe. That is a fact."

 
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