Tuesday, 7 April 2015

Suppressing old memories key to learning new ones

There has long been convincing evidence that recalling a memory can cause changes in that memory, potentially weakening it, strengthening it, or otherwise altering it. A new study, published in Nature Neuroscience by researchers from the University of Birmingham, the MRC Cognition and Brain Sciences Unit, and the Behavioral and Clinical Neurosciences Institute, presents a convincing argument that the weakening of old memories may be an adaptive function, one that helps the brain integrate new memories with existing ones.

The researchers were able to watch subjects’ brain activity as memories were recalled using a functional Magnetic Resonance Imaging (fMRI) machine. An fMRI machine allows scientists to see changes in brain activity by producing images that show where oxygen-rich blood is flowing within the brain.

Subjects were shown 144 pairs of pictures/words while in the fMRI machine, and their brain activity was observed. Then, the subjects entered a learning phase, in which they were trained on 72 picture-word pairs, a subset of the initial 144. They were asked to construct a highly detailed association between the pictures and the words, using intricate mental imagery. They were then asked to learn a second set of associations for each word; these served as competition for the first set.

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Strength in Numbers

Researchers develop the first-ever quantum device that detects and corrects its own errors When scientists develop a full

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Don’t Blink: A Light Show in a Dynamic Stellar Nursery

Changes in the universe don’t often happen on human timescales. In the cosmic “blink of an eye,” astronomers

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5 ways good science goes bad

Good science is a continual process, susceptible at many points to introduced errors and outright manipulation by the misguided and the devious. It's critically important, as public faith in science continues to be tested, to take an honest look at some of the ways good science can be turned into something that misleads and erodes public trust.

1. Publication bias stunts the free flow of ideas

Publication in a top journal like Nature or The New England Journal of Medicine is the "coin of the realm" in science, says Ivan Oransky, vice president and global editorial director of MedPage Today and the founder of Embargo Watch. Unfortunately, research has shown that journals suffer from publication bias — subjectively favoring some studies over others.

"Positive publication bias" is the tendency for the leading journals to print positive studies and avoid publishing negative ones. Oransky notes that many journals make revenue from selling copies of published studies. When pharmaceutical companies use positive clinical trial results in their drug sales pitches, for example, they pay for many reprints — reducing the incentive for journals to run less lucrative stories on drug trials that didn't work out.

It helps with any journal's branding to publish ooh-ahh findings and breakthrough discoveries that result in citations in other papers, and that "impact factor" can introduce a different bias. "There's a straight line between the sexiness of a study's results and its number of citations," Oransky says. With a premium on papers with citation-worthy big outcomes, prestigious journals sometimes overlook basic but useful research papers.

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The case of the antidepressant reboxetine is one example of publication bias. Ben Goldacre, a doctor and author of The Guardian's Bad Science column working hard to blow the whistle on publication bias, discovered that seven clinical trials had been conducted on the drug. Only one — the one with the smallest number of participants — found reboxetine had a marked benefit vs. a placebo. That study was published, and the other six were not, giving doctors a false impression of consensus.

2. Scientists commit fraud, leading to retractions

(iStock)

Each year, more than a million scientific papers are published in hundreds of peer-reviewed journals…and between 400 to 500 of these are later retracted. That's a very small percentage, admits Adam Marcus, the managing editor of two medical publications and co-founder, with Oransky, of the watchdog blog Retraction Watch. The big problem, Marcus says, is that two-thirds of retractions stem from researcher misconduct — fraud, fabrication, plagiarism, or other ethical failures. The general public may not hear about every retraction, but some cases are so egregious they make headlines.

Take discredited anesthesiologist Scott Reuben. In 2009, he admitted fabricating data in 21 papers that praised the benefits of pain drugs like Celebrex and Lyrica. Or Haruko Obokata, a stem-cell researcher at Japan's top institute, who had two papers published in Nature retracted this year. Obokata claimed she found a way to generated embryonic stem cells from an adult cell through simple stress, but her peers were unable to replicate the blockbuster results. But the world-record holder, according to Marcus, is Japanese anesthesiologist Yoshitaka Fujii with a grand total of 173 retractions for various offenses.

This kind of shoddy science, when widely reported, can have disastrous long-term impact. Disgraced British researcher Andrew Wakefield claimed, in a 1998 paper, that the measles, mumps, and rubella (MMR) vaccine could cause autism in children. Following its investigation in 2011, the British Medical Journal said Wakefield had misrepresented his 12 study subjects (some of whom did not have autism at all) and willfully faked data. But the widely-cited results of this flawed study became the foundation of an anti-vaccine movement putting untold numbers of children at risk today.

As comfortingly low as the overall percentage of retractions may be, that number has increased tenfold since 1975. Greater scrutiny from watchdog groups and investigative journalists are bringing the growing problem into the open, in hopes of stemming the tide.

3. Disinformation spreads, impairing public understanding of science

The infamous Climategate scandal is a shining example of what can go wrong when the scientific process meets conspiracy theory. Anonymous hackers broke into servers at the University of East Anglia's Climate Research Unit in November 2009, stealing thousands of private documents and emails, just before world leaders gathered to discuss climate change solutions at a meeting in Copenhagen. Global warming skeptics said that the unvarnished conversations proved that scientists had cooked up anthropogenic change as a vast environmental conspiracy.

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The researchers, including Michael Mann, said their emails had been taken out of context, and critics said the timing of the hack was suspicious. Multiple independent investigators combed the documents for scientific misconduct and found nothing, but the damage had been done. A Yale University survey in 2010 found that the public's belief in anthropogenic climate change and its trust in scientists had fallen significantly following the Climategate kerfuffle. Journalists and science educators are still trying to combat the incorrect impression that climate change is a hoax.

4. Scientists flock to well-funded fields, increasing risk of distorted results

(Spencer Platt/Getty Images)

It's tempting to follow the money. When the government, corporations, or foundations announce a major initiative to fund a specific type of research, there's an obvious incentive for scientists to flock to that field. Oransky says that some universities encourage its post-docs to use "keywords" like cancer or HIV in their proposals, or spin their project descriptions to suggest a real-world outcome for the average Joe, to attract the attention of the big grant-givers. Industry funders, in turn, might try to control the parameters of a study once they release its funding.

A 2010 study led by Trinity College economics researcher William Butos found three major consequences when the bulk of research funding comes from a handful of major institutions: "Effects on the choices of research activity, destabilizing effects (both long-run and short-run) on physical arrangements and resources supporting science and on the employment of scientists themselves, and distorting effects on the procedures scientists use to generate and validate scientific knowledge." And, there's an even greater chance of distortion when the funder exerts regulatory oversight.

The byproduct of this scenario? Fewer scientists focus on untrendy, poorly-funded research; and scientists in the better-funded fields have a greater risk of distorted results. It's a lose-lose scenario, which will likely continue as long as a small number of superrich funders are pulling the majority of the strings.

5. Science is skewed to suit political and corporate agendas

Politicians can be quick to misinterpret science to push their agenda or shape their message, but the media is no better when it comes to reporting on climate change. Cable news outlets discuss global warming with wildly varying degrees of accuracy, a UCS survey found: Fox News is scientifically accurate only 28 percent of the time, while MSNBC gets it right 92 percent of the time.

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Earlier this year, conservative lawmakers pounced on reports of a lull in the rate of Earth's surface warming — badly misworded as a "global warming pause" — as proof that global warming had stopped or had never really existed at all. Researchers, however, explained that the increasing amount of heat trapped in Earth's atmosphere affects oceans much more than land, so surface temperature isn't an accurate tool for measuring all the warming that's actually occurring, but it was a point largely lost on the audience.

As fallible as scientists can be, censoring them from speaking creates its own kind of damaging distortion, as their biased counterparts in the political and corporate spheres are not similarly restrained. The U.S. Environmental Protection Agency has moved to prohibit its scientists and independent advisers from talking to reporters without permission, and the Canadian government has prevented its climatologists from holding press conferences or speaking to the media. In hearings before the House Committee on Science, Space and Technology of the 112th Congress, industry witnesses from oil and gas, aerospace, computer and agriculture corporations outnumbered academic and independent witnesses.

 
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Massive Antarctic glacier more vulnerable than previously thought

The effect that the expansion of warming ocean water has on sea level is easy to predict. You just plug the value for a given amount of warming into a physical calculation. The contributions from melting glacial ice, however, are much trickier to divine. It depends heavily on fine-scale details, like the shape of the surface beneath the ice, which controls the glacier’s flow toward the sea.

Those fine-scale details aren’t easy to come by—not least because of the difficulty of accessing what can be remote and frigid places. While it’s expensive, field work can fill in key unknowns and reveal some of these glaciers’ histories, informing our estimates of future behavior.

The East Antarctic Ice Sheet isn’t as fragile as its western counterpart, but it is much, much larger. The biggest individual outlet glacier for East Antarctic ice is the Totten Glacier. On its own, the ice behind Totten could raise global sea level more than three meters if it were to melt completely. These frozen giants are generally slow to stir, but like most glaciers around the world, Totten is shrinking. The large floating ice shelf in front of Totten, which holds back the flow of ice like a buttress, is thinning at a rate in the neighborhood of 10 meters per year.

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Galileo satellites enclosed for Friday’s launch

Thousands of engineers have worked on the seventh and eighth navigation satellites of Europe’s Galileo constellation in recent

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How many times do I have to report a Google plus account that is not a real person and is used...

How many times do I have to report a Google plus account that is not a real person and is used only to spam blog posts before it is removed? So far I have reported it for spamming my comments around 30 times.

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First Scientific Publication from Data Collected at NSLS-II

Just weeks after the National Synchrotron Light Source II (NSLS-II) achieved first light, the team of scientists at

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Black hole winds pull the plug on star formation

Astronomers using ESA’s Herschel space observatory have found that the winds blowing from a huge black hole are

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