Humans were already recycling 13,000 years ago, burnt artifacts show

ScienceDaily (Sep. 20, 2012) — A study at the Universitat Rovira i Virgili and the Catalan Institute of Human Paleoecology and Social Evolution (IPHES) reveals that humans from the Upper Palaeolithic Age recycled their stone artefacts to be put to other uses. The study is based on burnt artefacts found in the Molí del Salt site in Tarragona, Spain.

The recycling of stone tools during Prehistoric times has hardly been dealt with due to the difficulties in verifying such practices in archaeological records. Nonetheless, it is possible to find some evidence, as demonstrated in a study published in the 'Journal of Archaeological Science'.

"In order to identify the recycling, it is necessary to differentiate the two stages of the manipulation sequence of an object: the moment before it is altered and the moment after. The two are separated by an interval in which the artefact has undergone some form of alteration. This is the first time a systematic study of this type has been performed," as explained to SINC by Manuel Vaquero, researcher at the Universitat Rovira i Virgili.

The archaeologists found a high percentage of burnt remains in the Molí del Salt site (Tarragona), which date back to the end of the Upper Palaeolithic Age some 13,000 years ago. The expert ensures that "we chose these burnt artefacts because they can tell us in a very simple way whether they have been modified after being exposed to fire."

The results indicate that the recycling of tools was normal during the Upper Palaeolithic Age. However, this practice is not documented in the same way as other types of artefacts. The use of recycled tools was more common for domestic activities and seems to be associated with immediate needs.

Recycling domestic tools

Recycling is linked to expedited behaviour, which means simply shaped and quickly available tools as and when the need arises. Tools used for hunting, like projectile points for instance, were almost never made from recycled artefacts. In contrast, double artefacts (those that combine two tools within the same item) were recycled more often.

"This indicates that a large part of these tools were not conceived from the outset as double artefacts but a single tool was made first and a second was added later when the artefact was recycled," outlines the researcher. The history of the artefacts and the sequence of changes that they have undergone over time are fundamental in understanding their final morphology.

According to Vaquero, "in terms of the objects, this is mostly important from a cultural value point of view, especially in periods like the Upper Palaeolithic Age, in which it is thought that the sharper the object the sharper the mind."

Sustainable practices with natural resources

Recycling could have been determinant in hunter-gatherer populations during the Palaeolithic Age if we consider the behaviour of current indigenous populations nowadays.

"It bears economic importance too, since it would have increased the availability of lithic resources, especially during times of scarcity. In addition, it is a relevant factor for interpreting sites because they become not just places to live but also places of resource provision," states the researcher.

Reusing resources meant that these humans did not have to move around to find raw materials to make their tools, a task that could have taken them far away from camp. "They would simply take an artefact abandoned by those groups who previously inhabited the site."

Vaquero and the team believe that this practice needs to be borne in mind when analysing the site. "Those populating these areas could have moved objects from where they were originally located. They even could have dug up or removed sediments in search of tools," highlights the researcher.

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The above story is reprinted from materials provided by Plataforma SINC, via AlphaGalileo.

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Journal Reference:

1. Manuel Vaquero, Susana Alonso, Sergio García-Catalán, Angélica García-Hernández, Bruno Gómez de Soler, David Rettig, María Soto. Temporal nature and recycling of Upper Paleolithic artifacts: the burned tools from the Molí del Salt site (Vimbodí i Poblet, northeastern Spain). Journal of Archaeological Science, 2012; 39 (8): 2785 DOI: 10.1016/j.jas.2012.04.024

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20 Sep, 2012

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Genetic mutation may have allowed early humans to migrate throughout Africa

ScienceDaily (Sep. 19, 2012) — A genetic mutation that occurred thousands of years ago might be the answer to how early humans were able to move from central Africa and across the continent in what has been called "the great expansion," according to new research from Wake Forest Baptist Medical Center.

By analyzing genetic sequence variation patterns in different populations around the world, three teams of scientists from Wake Forest Baptist, Johns Hopkins University School of Medicine and the University of Washington School of Medicine, Seattle, demonstrated that a critical genetic variant arose in a key gene cluster on chromosome 11, known as the fatty acid desaturase cluster or FADS, more than 85,000 years ago. This variation would have allowed early humans to convert plant-based polyunsaturated fatty acids (PUFAs) to brain PUFAs necessary for increased brain size, complexity and function. The FADS cluster plays a critical role in determining how effectively medium-chain PUFAs found in plants are converted to the long-chain PUFAs found in the brain.

This research is published online today in PLOS ONE.

Archeological and genetic studies suggest that homo sapiens appeared approximately 180,000 years ago, but stayed in one location around bodies of water in central Africa for almost 100,000 years. Senior author Floyd H. "Ski" Chilton, Ph.D., professor of physiology and pharmacology and director of the Center for Botanical Lipids and Inflammatory Disease Prevention at Wake Forest Baptist, and others have hypothesized that this location was critical, in part, because early humans needed large amounts of the long-chain PUFA docosahexaenoic acid (DHA), which is found in shellfish and fish, to support complex brain function.

"This may have kept early humans tethered to the water in central Africa where there was a constant food source of DHA," Chilton said. "There has been considerable debate on how early humans were able to obtain sufficient DHA necessary to maintain brain size and complexity. It's amazing to think we may have uncovered the region of genetic variation that arose about the time that early humans moved out of this central region in what has been called the 'great expansion.'"

Once this trait arose, the study shows that it was under intense selective pressure and thus rapidly spread throughout the population of the entire African continent. "The power of genetics continually impresses me, and I find it remarkable that we can make inferences about things that happened tens of thousands of years ago by studying patterns of genetic variation that exist in contemporary populations," said Joshua M. Akey, Ph.D., lead scientist at the University of Washington.

This conversion meant that early humans didn't have to rely on just one food source, fish, for brain growth and development. This may have been particularly important because the genetic variant arose before organized hunting and fishing could have provided more reliable sources of long-chain PUFAs, Akey said.

To investigate the evolutionary forces shaping patterns of variation in the FADS gene cluster in geographically diverse populations, the researchers analyzed 1,092 individuals representing 15 different human populations that were sequenced as part of the 1000 Genome Project and 1,043 individuals from 52 populations from the Human Genome Diversity Panel database. They focused on the FADS cluster because they knew those genes code for the enzymatic steps in long-chain PUFA synthesis that are the least efficient.

Chilton said the findings were possible because of the collaboration of internationally recognized scientists from three distinct and diverse disciplines -- fatty acid biochemistry (Wake Forest Baptist), statistical genetics (Johns Hopkins) and population genetics (University of Washington). This new information builds on Chilton's 2011 research findings published in BMC Genetics that showed how people of African descent have a much higher frequency of the gene variants that convert plant-based medium-chain omega-6 PUFAs found in cooking oils and processed foods to long-chain PUFAs that cause inflammation. Compared to Caucasians, African Americans in the United States have much higher rates of hypertension, type 2 diabetes, stroke, coronary heart disease and certain types of cancer. "The current observation provides another important clue as to why diverse racial and ethnic populations likely respond differently to the modern western diet," Chilton said.

This research was supported by National Institutes of Health grants, P50 AT002782 and a Clinical and Translational Science Award grant to The Johns Hopkins Medical Institutions. Additional support was received from the Wake Forest Health Sciences Center for Public Health Genomics. Additional support came from the Mary Beryl Patch Turnbull Scholar Program and the MOSAIC initiative of Johns Hopkins University.

Chilton has a financial interest in and is a consultant for Gene Smart Health. His potential conflict of interest is being institutionally managed by Wake Forest Baptist and outside sponsors, as appropriate. No other authors have a conflict of interest.

First author is Rasika Mathias, Sc.D, assistant professor of medicine and epidemiology, Johns Hopkins; contributing authors include Hannah C. Ainsworth and Susan Sergeant, both of Wake Forest Baptist; Wenqing Fu, U of W; Dara G. Torgerson, University of California San Francisco; and Ingo Ruczinski and Kathleen C. Barnes of Johns Hopkins.

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The above story is reprinted from materials provided by Wake Forest Baptist Medical Center.

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Journal Reference:

1. Rasika A. Mathias, Wenqing Fu, Joshua M. Akey, Hannah C. Ainsworth, Dara G. Torgerson, Ingo Ruczinski, Susan Sergeant, Kathleen C. Barnes, Floyd H. Chilton. Adaptive Evolution of the FADS Gene Cluster within Africa. PLoS ONE, 2012; 7 (9): e44926 DOI: 10.1371/journal.pone.0044926

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20 Sep, 2012

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Ancient tooth may provide evidence of early human dentistry

ScienceDaily (Sep. 19, 2012) — Researchers may have uncovered new evidence of ancient dentistry in the form of a 6,500-year-old human jaw bone with a tooth showing traces of beeswax filling, as reported Sept. 19 in the open access journal PLOS ONE.

The researchers, led by Federico Bernardini and Claudio Tuniz of the Abdus Salam International Centre for Theoretical Physics in Italy in cooperation with Sincrotrone Trieste and other institutions, write that the beeswax was applied around the time of the individual's death, but cannot confirm whether it was shortly before or after. If it was before death, however, they write that it was likely intended to reduce pain and sensitivity from a vertical crack in the enamel and dentin layers of the tooth.

According to Tuniz, the severe wear of the tooth "is probably also due to its use in non-alimentary activities, possibly such as weaving, generally performed by Neolithic females."

Evidence of prehistoric dentistry is sparse, so this new specimen, found in Slovenia near Trieste, may help provide insight into early dental practices.

"This finding is perhaps the most ancient evidence of pre-historic dentistry in Europe and the earliest known direct example of therapeutic-palliative dental filling so far," says Bernardini.

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1. Federico Bernardini, Claudio Tuniz, Alfredo Coppa, Lucia Mancini, Diego Dreossi, Diane Eichert, Gianluca Turco, Matteo Biasotto, Filippo Terrasi, Nicola De Cesare, Quan Hua, Vladimir Levchenko. Beeswax as Dental Filling on a Neolithic Human Tooth. PLoS ONE, 2012; 7 (9): e44904 DOI: 10.1371/journal.pone.0044904

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20 Sep, 2012

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Single-atom writer a landmark for quantum computing

ScienceDaily (Sep. 19, 2012) — A research team led by Australian engineers has created the first working quantum bit based on a single atom in silicon, opening the way to ultra-powerful quantum computers of the future.

In a landmark paper published September 19 in the journal Nature, the team describes how it was able to both read and write information using the spin, or magnetic orientation, of an electron bound to a single phosphorus atom embedded in a silicon chip.

"For the first time, we have demonstrated the ability to represent and manipulate data on the spin to form a quantum bit, or 'qubit', the basic unit of data for a quantum computer," says Scientia Professor Andrew Dzurak. "This really is the key advance towards realising a silicon quantum computer based on single atoms."

Dr Andrea Morello and Professor Dzurak from the UNSW School of Electrical Engineering and Telecommunications lead the team. It includes researchers from the University of Melbourne and University College, London.

"This is a remarkable scientific achievement -- governing nature at its most fundamental level -- and has profound implications for quantum computing," says Dzurak.

Dr Morello says that quantum computers promise to solve complex problems that are currently impossible on even the world's largest supercomputers: "These include data-intensive problems, such as cracking modern encryption codes, searching databases, and modelling biological molecules and drugs."

The new finding follows on from a 2010 study also published in Nature, in which the same UNSW group demonstrated the ability to read the state of an electron's spin. Discovering how to write the spin state now completes the two-stage process required to operate a quantum bit.

The new result was achieved by using a microwave field to gain unprecedented control over an electron bound to a single phosphorus atom, which was implanted next to a specially-designed silicon transistor. Professor David Jamieson, of the University of Melbourne's School of Physics, led the team that precisely implanted the phosphorus atom into the silicon device.

UNSW PhD student Jarryd Pla, the lead author on the paper, says: "We have been able to isolate, measure and control an electron belonging to a single atom, all using a device that was made in a very similar way to everyday silicon computer chips."

As Dr Morello notes: "This is the quantum equivalent of typing a number on your keyboard. This has never been done before in silicon, a material that offers the advantage of being well understood scientifically and more easily adopted by industry. Our technology is fundamentally the same as is already being used in countless everyday electronic devices, and that's a trillion-dollar industry."

The team's next goal is to combine pairs of quantum bits to create a two-qubit logic gate -- the basic processing unit of a quantum computer.

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Journal Reference:

1. Jarryd J. Pla, Kuan Y. Tan, Juan P. Dehollain, Wee H. Lim, John J. L. Morton, David N. Jamieson, Andrew S. Dzurak, Andrea Morello. A single-atom electron spin qubit in silicon. Nature, 2012; DOI: 10.1038/nature11449

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20 Sep, 2012

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Thermoelectric material is the best at converting heat waste to electricity

ScienceDaily (Sep. 19, 2012) — Northwestern University scientists have developed a thermoelectric material that is the best in the world at converting waste heat to electricity. This is very good news once you realize nearly two-thirds of energy input is lost as waste heat.

The material could signify a paradigm shift. The inefficiency of current thermoelectric materials has limited their commercial use. Now, with a very environmentally stable material that is expected to convert 15 to 20 percent of waste heat to useful electricity, thermoelectrics could see more widespread adoption by industry.

Possible areas of application include the automobile industry (much of gasoline's potential energy goes out a vehicle's tailpipe), heavy manufacturing industries (such as glass and brick making, refineries, coal- and gas-fired power plants) and places were large combustion engines operate continuously (such as in large ships and tankers).

Waste heat temperatures in these areas can range from 400 to 600 degrees Celsius (750 to 1,100 degrees Fahrenheit), the sweet spot for thermoelectrics use.

The new material, based on the common semiconductor lead telluride, is the most efficient thermoelectric material known. It exhibits a thermoelectric figure of merit (so-called "ZT") of 2.2, the highest reported to date. Chemists, physicists, material scientists and mechanical engineers at Northwestern and Michigan State University collaborated to develop the material.

The study will be published Sept. 20 by the journal Nature.

"Our system is the top-performing thermoelectric system at any temperature," said Mercouri G. Kanatzidis, who led the research and is a senior author of the paper. "The material can convert heat to electricity at the highest possible efficiency. At this level, there are realistic prospects for recovering high-temperature waste heat and turning it into useful energy."

Kanatzidis is Charles E. and Emma H. Morrison Professor of Chemistry in Northwestern's Weinberg College of Arts and Sciences. He also holds a joint appointment at Argonne National Laboratory.

"People often ask, what is the energy solution?" said Vinayak P. Dravid, one of Kanatzidis' close collaborators. "But there is no unique solution -- it's going to be a distributed solution. Thermoelectrics is not the answer to all our energy problems, but it is an important part of the equation."

Dravid is the Abraham Harris Professor of Materials Science and Engineering at the McCormick School of Engineering and Applied Science and a senior author of the paper.

Other members of the team and authors of the Nature paper include Kanishka Biswas, a postdoctoral fellow in Kanatzidis' group; Jiaqing He, a postdoctoral member in Dravid's group; David N. Seidman, Walter P. Murphy Professor of Materials Science and Engineering at Northwestern; and Timothy P. Hogan, professor of electrical and computer engineering, at Michigan State University.

Even before the Northwestern record-setting material, thermoelectric materials were starting to get better and being tested in more applications. The Mars rover Curiosity is powered by lead telluride thermoelectrics (although it's system has a ZT of only 1, making it half as efficient as Northwestern's system), and BMW is testing thermoelectrics in its cars by harvesting heat from the exhaust system.

"Now, having a material with a ZT greater than two, we are allowed to really think big, to think outside the box," Dravid said. "This is an intellectual breakthrough."

"Improving the ZT never stops -- the higher the ZT, the better," Kanatzidis said. "We would like to design even better materials and reach 2.5 or 3. We continue to have new ideas and are working to better understand the material we have."

The efficiency of waste heat conversion in thermoelectrics is governed by its figure of merit, or ZT. This number represents a ratio of electrical conductivity and thermoelectric power in the numerator (which need to be high) and thermal conductivity in the denominator (which needs to be low).

"It is hard to increase one without compromising the other," Dravid said. These contradictory requirements stalled the progress towards a higher ZT for many years, where it was stagnant at a nominal value of 1.

Kanatzidis and Dravid have pushed the ZT higher and higher in recent years by introducing nanostructures in bulk thermoelectrics. In January 2011, they published a report in Nature Chemistry of a thermoelectric material with a ZT of 1.7 at 800 degrees Kelvin. This was the first example of using nanostructures (nanocrystals of rock-salt structured strontium telluride) in lead telluride to reduce electron scattering and increase the energy conversion efficiency of the material.

The performance of the new material reported now in Nature is nearly 30 percent more efficient than its predecessor. The researchers achieved this by scattering a wider spectrum of phonons, across all wavelengths, which is important in reducing thermal conductivity.

"Every time a phonon is scattered the thermal conductivity gets lower, which is what we want for increased efficiency," Kanatzidis said.

A phonon is a quantum of vibrational energy, and each has a different wavelength. When heat flows through a material, a spectrum of phonons needs to be scattered at different wavelengths (short, intermediate and long).

In this work, the researchers show that all length scales can be optimized for maximum phonon scattering with minor change in electrical conductivity. "We combined three techniques to scatter short, medium and long wavelengths all together in one material, and they all work simultaneously," Kanatzidis said. "We are the first to scatter all three at once and at the widest spectrum known. We call this a panoscopic approach that goes beyond nanostructuring."

"It's a very elegant design," Dravid said.

In particular, the researchers improved the long-wavelength scattering of phonons by controlling and tailoring the mesoscale architecture of the nanostructured thermoelectric materials. This resulted in the world record of a ZT of 2.2.

The successful approach of integrated all-length-scale scattering of phonons is applicable to all bulk thermoelectric materials, the researchers said.

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The above story is reprinted from materials provided by Northwestern University, via EurekAlert!, a service of AAAS.

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Journal Reference:

1. Kanishka Biswas, Jiaqing He, Ivan D. Blum, Chun-I Wu, Timothy P. Hogan, David N. Seidman, Vinayak P. Dravid, Mercouri G. Kanatzidis. High-performance bulk thermoelectrics with all-scale hierarchical architectures. Nature, 2012; 489 (7416): 414 DOI: 10.1038/nature11439

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20 Sep, 2012

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Medication effective in treating social withdrawal in Fragile X and potentially autism patients

ScienceDaily (Sep. 19, 2012) — An investigational compound that targets the core symptoms of fragile X syndrome is effective for addressing the social withdrawal and challenging behaviors characteristic of the condition, making it the first such discovery for fragile X syndrome and, potentially, the first for autism spectrum disorder, a study by researchers at Rush University Medical Center and the University of California, Davis MIND Institute has found.

The finding is the result of a clinical trial in adult and pediatric subjects with fragile X syndrome. It suggests, however, that the compound may have treatment implications for at least a portion of the growing population of individuals with autism spectrum disorder, as well as for those with other conditions defined by social deficits. The study is published online September 19 in the journal Science Translational Medicine.

"There are no FDA-approved treatments for fragile X syndrome, and the available options help secondary symptoms but do not effectively address the core impairments in fragile X syndrome," said Dr. Elizabeth Berry-Kravis, the lead author of the article. "This is the first large-scale study that is based on the molecular understanding of fragile X syndrome and, importantly, suggests that the core symptoms may be amenable to pharmacologic treatment." Berry-Kravis is professor of Pediatrics, Neurological Sciences, and Biochemistry at Rush.

The "first-in-patient" drug trial was led by Berry-Kravis and Dr. Randi Hagerman of the UC Davis MIND Institute. It examined the effects of the compound STX 209, also known by the name Arbaclofen. The study was conducted collaboratively with Seaside Theraputics, a Cambridge, Mass., pharmaceutical company, that is focused on translating bench research on fragile X and autism into therapeutic interventions. Seaside Therapeutics produces the compound.

"This study shows that STX 209 is an important part of the treatment for fragile X syndrome, because it improved symptoms in those with significant social deficits or autism as well as fragile X syndrome," said Hagerman, who is the medical director of the MIND Institute. "Additional studies also are suggesting that STX 209 can be helpful for autism without fragile X syndrome. Until now, there have been no targeted treatments available for autism. This appears to be the first."

Fragile X syndrome is the most common known cause of inherited intellectual impairment, formerly referred to as mental retardation, and the leading known single-gene cause of autism. Social impairment is one of the core deficits in both fragile X and autism. The U.S. Centers for Disease Control and Prevention (CDC) estimates that about 1 in 4,000 males and 1 in 6,000 to 8,000 females have the disorder. An estimated 1 in 88 children born today will be diagnosed with autism, according to the CDC.

"This study will help to signal the beginning of a new era of targeted treatments for genetic disorders that have historically been regarded as beyond the reach of pharmacotherapy," Berry-Kravis said. "It will be a model for treatment of autism, intellectual disability and developmental brain disorders based on understanding of dysfunction in brain pathways, as opposed to empiric treatment of symptoms. We hope mechanistically-based treatments like STX209 ultimately will be shown to improve cognitive functioning in longer-term trials."

Studies in mice genetically engineered to exhibit features of fragile X, including social impairment, have suggested that the behavioral abnormalities in fragile X result from deficiencies in the neurotransmitter gamma-amino butyric acid (GABA). Decreased GABA has been observed in a mouse model of fragile X in many areas of the brain including the hippocampus, and has been hypothesized to be a basis of the social anxiety and avoidance characteristic of fragile X sufferers, the study says.

Arbaclofen is an agonist for gamma-amino butyric acid type B, or GABA-B, receptors. An agonist is a chemical that effectively combines with a receptor on a synapse to effect a physiologic reaction typical of a naturally occurring substance. Anxiety-driven repetitive behavior and social avoidance have been reduced in fragile X-engineered mice treated with arbaclofen. The current, first-of-its-kind study investigated whether Arbaclofen would produce similar results in human subjects.

The double-blind, placebo-controlled clinical trial initially recruited 63 subjects at 12 sites across the United States for the research, conducted between December 2008 and March 2010. The participants ranged in age from 6 to 39 years. Of the initial participants, 56 completed the clinical trial. There were no withdrawals related to drug tolerability. The majority of the subjects were treated with what was assessed as the optimum tolerated dosage of the study drug, 10 milligrams twice a day in younger patients and three times a day in adults. Compliance was monitored by patient guardians, who filled out a dosing form on a daily basis.

The study subjects returned for evaluations at two- and four-week intervals after beginning the six-week-long treatment. The drug then was tapered down over a one- to two-week period. After a week, the subjects entered a second treatment period.

The effects of the medication were scored on variables of the Aberrant Behavior Checklist, a behavior-rating scale for the assessment of drug-treatment effects. The checklist includes variables for irritability, lethargy/withdrawal, stereotypic (repetitive) behavior and hyperactivity, among other factors.

The study found improvement for the full study population on the social-avoidance subscale, an analysis validated by secondary ratings from parent observation of improvement in subjects' three most problematic behaviors. It found that the medication was the same as placebo, however, on the subscale for irritability.

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The above story is reprinted from materials provided by Rush University Medical Center, via EurekAlert!, a service of AAAS.

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Journal Reference:

1. E. M. Berry-Kravis, D. Hessl, B. Rathmell, P. Zarevics, M. Cherubini, K. Walton-Bowen, Y. Mu, D. V. Nguyen, J. Gonzalez-Heydrich, P. P. Wang, R. L. Carpenter, M. F. Bear, R. J. Hagerman. Effects of STX209 (Arbaclofen) on Neurobehavioral Function in Children and Adults with Fragile X Syndrome: A Randomized, Controlled, Phase 2 Trial. Science Translational Medicine, 2012; 4 (152): 152ra127 DOI: 10.1126/scitranslmed.3004214

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Disclaimer: This article is not intended to provide medical advice, diagnosis or treatment. Views expressed here do not necessarily reflect those of ScienceDaily or its staff.

20 Sep, 2012

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Using a laser to 'see' the smallest world: Powerful laser breathes new life into an old technology for studying atomic-level structures

ScienceDaily (Sep. 19, 2012) — A multi-university team has employed a high-powered laser based at UC Santa Barbara to dramatically improve one of the tools scientists use to study the world at the atomic level. The team used their amped-up electron paramagnetic resonance (EPR) spectrometer to study the electron spin of free radicals and nitrogen atoms trapped inside a diamond.

The improvement will pull back the veil that shrouds the molecular world, allowing scientists to study tiny molecules at a high resolution.

The team, which includes researchers from UCSB, University of Southern California (USC), and Florida State University, published its findings this week in Nature.

"We developed the world's first free-electron laser-powered EPR spectrometer," said Susumu Takahashi, assistant professor of chemistry at the USC Dornsife College of Letters, Arts and Sciences, and lead author of the Nature paper. "This ultra high-frequency, high-power EPR system gives us extremely good time resolution. For example, it enables us to film biological molecules in motion."

By using a high-powered laser, the researchers were able to significantly enhance EPR spectroscopy, which uses electromagnetic radiation and magnetic fields to excite electrons. These excited electrons emit electromagnetic radiation that reveals details about the structure of the targeted molecules.

EPR spectroscopy has existed for decades. Its limiting factor is the electromagnetic radiation source used to excite the electrons -- it becomes more powerful at high magnetic fields and frequencies, and, when targeted, electrons are excited with pulses of power as opposed to continuous waves.

Until now, scientists performed pulsed EPR spectroscopy with a few tens of GHz of electromagnetic radiation. Using UCSB's free electron laser (FEL), which emits a pulsed beam of electromagnetic radiation, the team was able to use 240 GHz of electromagnetic radiation to power an EPR spectrometer.

"Each electron can be thought of as a tiny magnet that senses the magnetic fields caused by atoms in its nano-neighborhood," said Mark Sherwin, professor of physics and director of the Institute for Terahertz Science and Technology at UCSB. "With FEL-powered EPR, we have shattered the electromagnetic bottleneck that EPR has faced, enabling electrons to report on faster motions occurring over longer distances than ever before. We look forward to breakthrough science that will lay foundations for discoveries like new drugs and more efficient plastic solar cells."

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Journal Reference:

1. S. Takahashi, L.-C. Brunel, D. T. Edwards, J. van Tol, G. Ramian, S. Han, M. S. Sherwin. Pulsed electron paramagnetic resonance spectroscopy powered by a free-electron laser. Nature, 2012; 489 (7416): 409 DOI: 10.1038/nature11437

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20 Sep, 2012

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Experiment corrects prediction in quantum theory

ScienceDaily (Sep. 19, 2012) — An international team of scientists is rewriting a page from the quantum physics rulebook using a University of Florida laboratory once dubbed the coldest spot in the universe.

Much of what we know about quantum mechanics is theoretical and tested via computer modeling because quantum systems, like electrons whizzing around the nucleus of an atom, are difficult to pin down for observation. One can, however, slow particles down and catch them in the quantum act by subjecting them to extremely cold temperatures. New research, published in the Sept. 20 edition of the journal Nature, describes how this freeze-frame approach was recently used to overturn an accepted rule of thumb in quantum theory.

"We are in the age of quantum mechanics," said Neil Sullivan, a UF physics professor and director of the National High Magnetic Field Laboratory High B/T Facility on the UF campus -- home of the Microkelvin lab where experiments can be conducted in near-absolute zero temperatures. "If you've had an MRI, you have made use of a quantum technology."

The magnet that powers an MRI scanner is a superconducting coil transformed into a quantum state by very cold liquid helium. Inside the coil, electric current flows friction free.

Quantum magnets and other strange, almost otherworldly occurrences in quantum mechanics could inspire the next big breakthroughs in computing, alternative energy and transportation technologies such as magnetic levitating trains, Sullivan said. But innovation cannot proceed without a proper set of guidelines to help engineers navigate the quantum road.

That's where the Microkelvin lab comes in. It is one of the few facilities in the world equipped to deliver the extremely cold temperatures needed to slow what Sullivan calls the "higgledy-piggledy" world of quantum systems at normal temperatures to a manageable pace where it can be observed and manipulated.

"Room temperature is approximately 300 kelvin," Sullivan said. "Liquid hydrogen pumped into a rocket at the Kennedy Space Center is at 20 kelvin."

Physicists need to cool things down to 1 millikelvin, one thousandth of a kelvin above absolute zero, or -459.67 degrees Fahrenheit, to bring matter into a different realm where quantum properties can be explored.

One fundamental state of quantum mechanics that scientists are keen to understand more fully is a fragile, ephemeral phase of matter called a Bose-Einstein Condensate. In this state, individual particles that make up a material begin to act as a single coherent unit. It's a tricky condition to induce in a laboratory setting, but one that researchers need to explore if technology is ever to fully exploit the properties of the quantum world.

Two theorists, Tommaso Roscilde at the University of Lyon, France, and Rong Yu from Rice University in Houston, developed the underlying ideas for the study and asked a colleague, Armando Paduan-Filho from the University of Sao Paulo in Brazil, to engineer the crystalline sample used in the experiment.

"Our measurements definitively tested an important prediction about a particular behavior in a Bose-Einstein Condensate," said Vivien Zapf, a staff scientist at the National High Magnetic Field Laboratory at Los Alamos and a driving force behind the international collaboration.

The experiment monitored the atomic spin of subatomic particles called bosons in the crystal to see when the transition to Bose-Einstein Condensate was achieved, and then further cooled the sample to document the exact point where the condensate properties decayed. They observed the anticipated phenomenon when they took the sample down to 1 millikelvin.

The crystal used in the experiment had been doped with impurities in an effort to create more of a real world scenario, Zapf said. "It's nice to know what happens in pure samples, but the real world, is messy and we need to know what the quantum rules are in those situations."

Having performed a series of simulations in advance, they knew that the experiment would require them to generate temperatures down to 1 millikelvin.

"You have to go to the Microkelvin Laboratory at UF for that," she said. The lab is housed within the National High Magnetic Field Laboratory High B/T Facility at UF, funded by the National Science Foundation. Other laboratories can get to the extreme temperature required, but none of them can sustain it long enough to collect all of the data needed for the experiment.

"It took six months to get the readings," said Liang Yin, an assistant scientist in the UF physics department who operated the equipment in the Microkelvin lab. "Because the magnetic field we used to control the wave intensity in the sample also heats it up. You have to adjust it very slowly."

Their findings literally rewrote the rule for predicting the conditions under which the transition would occur between the two quantum states.

"All the world should be watching what happens as we uncover properties of systems at these extremely low temperatures," Sullivan said. "A superconducting wire is superconducting because of this Bose-Einstein Condensation concept. If we are ever to capitalize on it for quantum computing or magnetic levitation for trains, we have to thoroughly understand it."

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The above story is reprinted from materials provided by University of Florida. The original article was written by Donna Hesterman.

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Journal Reference:

1. Rong Yu, Liang Yin, Neil S. Sullivan, J. S. Xia, Chao Huan, Armando Paduan-Filho, Nei F. Oliveira Jr, Stephan Haas, Alexander Steppke, Corneliu F. Miclea, Franziska Weickert, Roman Movshovich, Eun-Deok Mun, Brian L. Scott, Vivien S. Zapf, Tommaso Roscilde. Bose glass and Mott glass of quasiparticles in a doped quantum magnet. Nature, 2012; 489 (7416): 379 DOI: 10.1038/nature11406

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20 Sep, 2012

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Human brains share a consistent genetic blueprint and possess enormous biochemical complexity

ScienceDaily (Sep. 19, 2012) — Scientists at the Allen Institute for Brain Science reported in the latest issue of the journal Nature that human brains share a consistent genetic blueprint and possess enormous biochemical complexity. The findings stem from the first deep and large-scale analysis of the vast data set publicly available in the Allen Human Brain Atlas.

The results of this study are based on extensive analysis of the Allen Human Brain Atlas, specifically the detailed all-genes, all-structures survey of genes at work throughout the human brain. This dataset profiles 400 to 500 distinct brain areas per hemisphere using microarray technology and comprises more than 100 million gene expression measurements covering three individual human brains to date. Among other findings, these data show that 84% of all genes are expressed somewhere in the human brain and in patterns that are substantially similar from one brain to the next.

"This study demonstrates the value of a global analysis of gene expression throughout the entire brain and has implications for understanding brain function, development, evolution and disease," said Ed Lein, Ph.D., Associate Investigator at the Allen Institute for Brain Science and co-lead author on the paper. "These results only scratch the surface of what can be learned from this immense data set. We look forward to seeing what others will discover."

Key Findings

The results of this study show that, despite the myriad personalities and cognitive talents seen across the human population, our brains are more similar to one another than different. Individual human brains share the same basic molecular blueprint, and deeper analysis of this shared architecture reveals several further findings:

• Neighboring regions of the brain's cortex -- the wrinkly outer rind -- are more biochemically similar to one another than to more distant brain regions, which has implications for understanding the development of the human brain, both during the lifespan and throughout evolution.
• The right and left hemispheres show no significant differences in molecular architecture. This suggests that functions such as language, which are generally handled by one side of the brain, likely result from more subtle differences between hemispheres or structural variation in size or circuitry, but not from a deeper molecular basis.
• Despite controlling a diversity of functions, ranging from visual perception to planning and problem-solving, the cortex is highly homogeneous relative to other brain regions. This suggests that the same basic functional elements are used throughout the cortex and that understanding how one area works in detail will uncover fundamentals that apply to the other areas, as well.

In addition to such global findings, the study provides new insights into the detailed inner workings of the brain at the molecular level -- the level at which diseases unfold and therapeutic drugs take action.

• 84% of all genes are expressed, or turned on, somewhere in the human brain.
• Many previously uncharacterized genes are turned on in specific brain regions and localize with known functional groups of genes, suggesting they play roles in particular brain functions.
• Synapse-associated genes -- those related to cell-to-cell communication machinery in the brain -- are deployed in complex combinations throughout the brain, revealing a great diversity of synapse types and remarkable regional variation that likely underlies functional distinctions between brain regions.

"The tremendous variety of synapses we see in the human brain is quite striking," said Seth Grant, FRSE, Professor of Molecular Neuroscience at the University of Edinburgh and collaborating author on the study. "Mutations in synaptic genes are associated with numerous brain-related disorders, and thus understanding synapse diversity and organization in the brain is a key step toward understanding these diseases and developing specific and effective therapeutics to treat them."

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The above story is reprinted from materials provided by Allen Institute for Brain Science.

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Journal Reference:

1. Michael J. Hawrylycz, Ed S. Lein, Angela L. Guillozet-Bongaarts, Elaine H. Shen, Lydia Ng, Jeremy A. Miller, Louie N. van de Lagemaat, Kimberly A. Smith, Amanda Ebbert, Zackery L. Riley, Chris Abajian, Christian F. Beckmann, Amy Bernard, Darren Bertagnolli, Andrew F. Boe, Preston M. Cartagena, M. Mallar Chakravarty, Mike Chapin, Jimmy Chong, Rachel A. Dalley, Barry David Daly, Chinh Dang, Suvro Datta, Nick Dee, Tim A. Dolbeare, Vance Faber, David Feng, David R. Fowler, Jeff Goldy, Benjamin W. Gregor, Zeb Haradon, David R. Haynor, John G. Hohmann, Steve Horvath, Robert E. Howard, Andreas Jeromin, Jayson M. Jochim, Marty Kinnunen, Christopher Lau, Evan T. Lazarz, Changkyu Lee, Tracy A. Lemon, Ling Li, Yang Li, John A. Morris, Caroline C. Overly, Patrick D. Parker, Sheana E. Parry, Melissa Reding, Joshua J. Royall, Jay Schulkin, Pedro Adolfo Sequeira, Clifford R. Slaughterbeck, Simon C. Smith, Andy J. Sodt, Susan M. Sunkin, Beryl E. Swanson, Marquis P. Vawter, Derric Williams, Paul Wohnoutka, H. Ronald Zielke, Daniel H. Geschwind, Patrick R. Hof, Stephen M. Smith, Christof Koch, Seth G. N. Grant, Allan R. Jones. An anatomically comprehensive atlas of the adult human brain transcriptome. Nature, 2012; 489 (7416): 391 DOI: 10.1038/nature11405

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Disclaimer: This article is not intended to provide medical advice, diagnosis or treatment. Views expressed here do not necessarily reflect those of ScienceDaily or its staff.

20 Sep, 2012

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The more people rely on their intuitions, the more cooperative they become

ScienceDaily (Sep. 19, 2012) — It's an age old question: Why do we do good? What makes people sometimes willing to put "We" ahead of "Me?" Perhaps our first impulse is to be selfish, and cooperation is all about reining in greed. Or maybe cooperation happens spontaneously, and too much thinking gets in the way.

Harvard scientists are getting closer to an answer, showing that people's first response is to cooperate and that stopping to think encourages selfishness.

David Rand, a Post-Doctoral Fellow in Psychology, Joshua Greene, the John and Ruth Hazel Associate Professor of the Social Sciences in the Department of Psychology, and Martin Nowak, Professor of Mathematics and of Biology, and Director of the Program for Evolutionary Dynamics, have published their findings in the September 20 issue of Nature. They recruited thousands of participants to play a "public goods game" in which it's "Me" vs. "Us." Subjects were put into small groups and faced with a choice: Keep the money you've been given, or contribute it into a common pool that grows and benefits the whole group. Hold onto the money and you come out ahead, but the group does best when everyone contributes.

The researchers wanted to know whether people's first impulse is cooperative or selfish. To find out, they started by looking at how quickly different people made their choices, and found that faster deciders were more likely to contribute to the common good.

Next they forced people to go fast or to stop and think, and found the same thing: Faster deciders tended to be more cooperative, and the people who had to stop and think gave less.

Finally, the researchers tested their hypothesis by manipulating people's mindsets. They asked some people to think about the benefits of intuition before choosing how much to contribute. Others were asked to think about the virtues of careful reasoning. Once again, intuition promoted cooperation, and deliberation did the opposite.

While some might interpret the results as suggesting that cooperation is "innate" or "hard-wired," if anything they highlight the role of experience. People who had better opinions of those around them in everyday life showed more cooperative impulses in these experiments, and previous experience with these kinds of studies eroded those impulses.

"In daily life, it's generally in your interest to be cooperative," Rand said. "So we internalize cooperation as the right way to behave. Then when we come into unusual environments, where incentives like reputation and sanctions are removed, our first response is to keep behaving the way we do in normal life. When we think about it, however, we realize that this is one of those rare situations where we can be selfish and get away with it."

Unlike many psychology studies, which use small numbers of college students, these experiments tested thousands of people from around the world using Amazon Mechanical Turk, an online labor market that's becoming an increasingly popular tool for social science research.

According to Rand, the findings highlight an interesting and counterintuitive truth -- that careful thought and reflection have a dark side. But is reflection always bad?

"When it's 'Me' vs. 'Us,' our intuitions seem to work well. That's what's going on here," explains Joshua Greene. "But what happens when people have different moral intuitions, for example, about abortion or raising taxes? When intuitions clash -- when it's the values of 'Us' vs. 'Them' -- reasoning and reflection may be our best hope for reconciling our differences."

"Over millions of years we've evolved the capacity for cooperation," explains Martin Nowak. "These psychological experiments examine the causes of cooperation on a shorter timescale, on the order of seconds. Both perspectives are essential as we face global problems which require cooperation on a massive scale. We need to understand where cooperation comes from historically and how best to make it happen here and now."

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The above story is reprinted from materials provided by Harvard University, via EurekAlert!, a service of AAAS.

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Journal Reference:

1. David G. Rand, Joshua D. Greene, Martin A. Nowak. Spontaneous giving and calculated greed. Nature, 2012; 489 (7416): 427 DOI: 10.1038/nature11467

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Disclaimer: This article is not intended to provide medical advice, diagnosis or treatment. Views expressed here do not necessarily reflect those of ScienceDaily or its staff.

20 Sep, 2012

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Ultra-distant galaxy discovered amidst cosmic 'dark ages': May be oldest galaxy ever

ScienceDaily (Sep. 19, 2012) — With the combined power of NASA's Spitzer and Hubble space telescopes as well as a cosmic magnification effect, a team of astronomers led by Wei Zheng of The Johns Hopkins University has spotted what could be the most distant galaxy ever detected.

Light from the young galaxy captured by the orbiting observatories shone forth when the 13.7-billion-year-old universe was just 500 million years old.

The far-off galaxy existed within an important era when the universe began to transit from the so-called "Dark Ages." During this period, the universe went from a dark, starless expanse to a recognizable cosmos full of galaxies. The discovery of the faint, small galaxy accordingly opens up a window into the deepest, remotest epochs of cosmic history.

"This galaxy is the most distant object we have ever observed with high confidence," said Zheng, a principal research scientist in The Henry A. Rowland Department of Physics and Astronomy at Johns Hopkins' Krieger School of Arts and Sciences and lead author of a paper appearing in Nature on Sept. 20. "Future work involving this galaxy -- as well as others like it that we hope to find -- will allow us to study the universe's earliest objects and how the Dark Ages ended."

Light from the primordial galaxy traveled approximately 13.2 billion light-years before reaching NASA's telescopes. In other words, the starlight snagged by Spitzer and Hubble left the galaxy when the universe was just 3.6 percent of its present age. Technically speaking, the galaxy has a redshift, or "z," of 9.6. The term "redshift" refers to how much an object's light has shifted into longer wavelengths as a result of the expansion of the universe. Astronomers use "redshift" to describe cosmic distances.

Unlike previous detections of galaxy candidates in this age range, which were only glimpsed in a single color, or waveband, this newfound galaxy has been seen in five different wavebands. As part of the Cluster Lensing and Supernova Survey with Hubble program (CLASH), the Hubble Space Telescope registered the newly described far-flung galaxy in four wavelength bands. Spitzer located it in a fifth band with its Infrared Array Camera (IRAC), placing the discovery on firmer ground.

Objects at these extreme distances are mostly beyond the detection sensitivity of today's largest telescopes. To catch sight of these early, distant galaxies, astronomers rely on "gravitational lensing." In this phenomenon -- predicted by Albert Einstein a century ago -- the gravity of foreground objects warps and magnifies the light from background objects. A massive galaxy cluster situated between our galaxy and the early galaxy magnified the latter's light, brightening the remote object some 15 times and bringing it into view.

Based on the Spitzer and Hubble observations, astronomers think the distant galaxy was spied at a time when it was less than 200 million years old. It also is small and compact, containing only about 1 percent of the Milky Way's mass. According to leading cosmological theories, the first galaxies should indeed have started out tiny. They then progressively merged, eventually accumulating into the sizable galaxies of the more modern universe.

These first galaxies likely played the dominant role in the epoch of reionization, the event that signaled the demise of the universe's Dark Ages. About 400,000 years after the Big Bang, neutral hydrogen gas formed from cooling particles. The first luminous stars and their host galaxies, however, did not emerge until a few hundred million years later. The energy released by these earliest galaxies is thought to have caused the neutral hydrogen strewn throughout the universe to ionize, or lose an electron, the state in which the gas has remained since that time.

"In essence, during the epoch of reionization, the lights came on in the universe," said paper co-author Leonidas Moustakas, a research scientist at NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, Calif.

Astronomers plan to study the rise of the first stars and galaxies and the epoch of reionization with the successor to both Spitzer and Hubble -- NASA's James Webb Telescope, slated for launch in 2018. The newly described distant galaxy will likely be a prime target.

Holland Ford, one of Zheng's colleagues and a co-author on the paper, commented on the findings.

"Science is very exciting when we explore the frontiers of knowledge," said Ford, a physics and astronomy professor at Johns Hopkins. "One of these frontiers is the first few hundred million years after the birth of our universe. Dr. Zheng's many years of searching for quasars and galaxies in the dawn of the universe has paid off with his discovery of a galaxy that we see as it was when the universe was less than 500 million years old.

"With his discovery, we are seeing a galaxy when it was not even a toddler," Ford said. "But this infant galaxy will in its future grow to be a galaxy like our own, hopefully hosting planetary systems with astronomers who will look back in time and see our galaxy in its infancy."

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The above story is reprinted from materials provided by Johns Hopkins University, via Newswise. The original article was written by Lisa DeNike.

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Journal Reference:

1. Wei Zheng, Marc Postman, Adi Zitrin, John Moustakas, Xinwen Shu, Stephanie Jouvel, Ole Høst, Alberto Molino, Larry Bradley, Dan Coe, Leonidas A. Moustakas, Mauricio Carrasco, Holland Ford, Narciso Benítez, Tod R. Lauer, Stella Seitz, Rychard Bouwens, Anton Koekemoer, Elinor Medezinski, Matthias Bartelmann, Tom Broadhurst, Megan Donahue, Claudio Grillo, Leopoldo Infante, Saurabh W. Jha, Daniel D. Kelson, Ofer Lahav, Doron Lemze, Peter Melchior, Massimo Meneghetti, Julian Merten, Mario Nonino, Sara Ogaz, Piero Rosati, Keiichi Umetsu, Arjen van der Wel. A magnified young galaxy from about 500 million years after the Big Bang. Nature, 2012; 489 (7416): 406 DOI: 10.1038/nature11446

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20 Sep, 2012

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CT scan and 3-D print help scientists reconstruct an ancient mollusk

ScienceDaily (Sep. 19, 2012) — Using a combination of traditional and innovative model-building techniques, scientists in the U.S. and a specialist in Denmark have created a lifelike reconstruction of an ancient mollusk, offering a vivid portrait of a creature that lived about 390 million years ago, and answering questions about its place in the tree of life, as described in the Sept. 18 edition of the journal Palaeontology.

The model of the oval-shaped sea creature, called a multiplacophoran, which was covered with stiff plates and a ring of spines, resulted from a collaboration between Jakob Vinther, a postdoctoral researcher at The University of Texas at Austin's Jackson School of Geosciences, and Esben Horn, owner of the model making company 10 Tons in Copenhagen (http://www.10tons.dk), with animation help from Ryan Carney, a doctoral student at Brown University.

Working with a delicate specimen of a multiplacophoran partially covered by rock, Vinther used a micro CT scan -- a noninvasive technology similar to medical CAT scanning -- to create a three-dimensional view of the fossil. With Carney's help, the CT scan yielded an animated view of the original placement of the creature's dense spines and shells, which had splayed out and decayed prior to fossilization.

The CT scan also produced a three-dimensional cast of the specimen in its reconstructed shape. Working with the cast, the animation and information on living relatives of the multiplacophorans, Horn was able to create a multicolored, textured model in clay, resin and silicone showing how the creature looked millions of years ago, when it crawled on a single, suction-like foot over shells and rocky surfaces in ancient oceans.

The model helps address a debate about how multiplacophorans (which were only discovered in the past decade) relate to chitons, another more widely known plated mollusk that lives on seashores and is commonly eaten in the Caribbean. By dating the origin of modern chitons, Vinther could demonstrate that multiplacophorans are stem group chitons.

"We can now demonstrate that multiplacophorans are distant relatives of the modern chitons, which did not evolve until later in Earth history," said Vinther. "We can also show that they evolved a number of characteristics seen in some modern chitons convergently."

The CT scan was integral to the project, allowing the scientists to see below the surface of the fossil.

"CT scanning is an extremely powerful technique for paleontologists," said Vinther, "since we can look inside fossils without destroying them."

The original fossil was discovered 10 years ago in Ohio by private collector and co-author George Kampouris, who donated it to the Cincinnati Museum of Natural History.

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Journal Reference:

1. Jakob Vinther, Peter Jell, George Kampouris, Ryan Carney, Rachel A. Racicot, Derek E. G. Briggs. The origin of multiplacophorans - convergent evolution in Aculiferan molluscs. Palaeontology, 2012; 55 (5): 1007 DOI: 10.1111/j.1475-4983.2012.01180.x

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20 Sep, 2012

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How organisms evolve new functions: Evolution is as complicated as 1-2-3

ScienceDaily (Sep. 19, 2012) — A team of researchers at Michigan State University has documented the step-by-step process in which organisms evolve new functions.

The results, published in the current issue of Nature, are revealed through an in-depth, genomics-based analysis that decodes how E. coli bacteria figured out how to supplement a traditional diet of glucose with an extra course of citrate.

"It's pretty nifty to see a new biological function evolve," said Zachary Blount, postdoctoral researcher in MSU's BEACON Center for the Study of Evolution in Action. "The first citrate-eaters were just barely able to grow on the citrate, but they got much better over time. We wanted to understand the changes that allowed the bacteria to evolve this new ability. We were lucky to have a system that allowed us to do so."

Normal E. coli can't digest citrate when oxygen is present. In fact, it's a distinct hallmark of E. coli. They can't eat citrate because E. coli don't express the right protein to absorb citrate molecules.

To decipher the responsible mutations, Blount worked with Richard Lenski, MSU Hannah Distinguished Professor of Microbiology and Molecular Genetics. Lenski's long-term experiment, cultivating cultures of fast-growing E. coli, was launched in 1988 and has allowed him and his teammates to study more than more than 56,000 generations of bacterial evolution.

The experiment demonstrates natural selection at work. And because samples are frozen and available for later study, when something new emerges scientists can go back to earlier generations to look for the steps that happened along the way.

"We first saw the citrate-using bacteria around 33,000 generations," Lenski explained. "But Zack was able to show that some of the important mutations had already occurred before then by replaying evolution from different intermediate stages. He showed you could re-evolve the citrate-eaters, but only after some of the other pieces of the puzzle were in place."

In the Nature paper, Blount and his teammates analyzed 29 genomes from different generations to find the mutational pieces of the puzzle. They uncovered a three-step process in which the bacteria developed this new ability.

The first stage was potentiation, when the E. coli accumulated at least two mutations that set the stage for later events. The second step, actualization, is when the bacteria first began eating citrate, but only just barely nibbling at it. The final stage, refinement, involved mutations that greatly improved the initially weak function. This allowed the citrate eaters to wolf down their new food source and to become dominant in the population.

"We were particularly excited about the actualization stage," Blount said. "The actual mutation involved is quite complex. It re-arranged part of the bacteria's DNA, making a new regulatory module that had not existed before. This new module causes the production of a protein that allows the bacteria to bring citrate into the cell when oxygen is present. That is a new trick for E. coli."

The change was far from normal, Lenski said.

"It wasn't a typical mutation at all, where just one base-pair, one letter, in the genome is changed," he said. "Instead, part of the genome was copied so that two chunks of DNA were stitched together in a new way. One chunk encoded a protein to get citrate into the cell, and the other chunk caused that protein to be expressed."

Additional co-authors include Jeff Barrick, University of Texas, and Carla Davidson, University of Calgary.

The research was funded in part by the National Science Foundation.

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Journal Reference:

1. Zachary D. Blount, Jeffrey E. Barrick, Carla J. Davidson, Richard E. Lenski. Genomic analysis of a key innovation in an experimental Escherichia coli population. Nature, 2012; DOI: 10.1038/nature11514

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20 Sep, 2012

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Your memory is like the telephone game, altered with each retelling

ScienceDaily (Sep. 19, 2012) — Remember the telephone game where people take turns whispering a message into the ear of the next person in line? By the time the last person speaks it out loud, the message has radically changed. It's been altered with each retelling.

Turns out your memory is a lot like the telephone game, according to a new Northwestern Medicine study.

Every time you remember an event from the past, your brain networks change in ways that can alter the later recall of the event. Thus, the next time you remember it, you might recall not the original event but what you remembered the previous time. The Northwestern study is the first to show this.

"A memory is not simply an image produced by time traveling back to the original event -- it can be an image that is somewhat distorted because of the prior times you remembered it," said Donna Bridge, a postdoctoral fellow at Northwestern University Feinberg School of Medicine and lead author of the paper on the study recently published in the Journal of Neuroscience. "Your memory of an event can grow less precise even to the point of being totally false with each retrieval."

Bridge did the research while she was a doctoral student in lab of Ken Paller, a professor of psychology at Northwestern in the Weinberg College of Arts and Sciences.

The findings have implications for witnesses giving testimony in criminal trials, Bridge noted.

"Maybe a witness remembers something fairly accurately the first time because his memories aren't that distorted," she said. "After that it keeps going downhill."

The published study reports on Bridge's work with 12 participants, but she has run several variations of the study with a total of 70 people. "Every single person has shown this effect," she said. "It's really huge."

"When someone tells me they are sure they remember exactly the way something happened, I just laugh," Bridge said.

The reason for the distortion, Bridge said, is the fact that human memories are always adapting.

"Memories aren't static," she noted. "If you remember something in the context of a new environment and time, or if you are even in a different mood, your memories might integrate the new information."

For the study, people were asked to recall the location of objects on a grid in three sessions over three consecutive days. On the first day during a two-hour session, participants learned a series of 180 unique object-location associations on a computer screen. The next day in session two, participants were given a recall test in which they viewed a subset of those objects individually in a central location on the grid and were asked to move them to their original location. Then the following day in session three, participants returned for a final recall test.

The results showed improved recall accuracy on the final test for objects that were tested on day two compared to those not tested on day two. However, people never recalled exactly the right location. Most importantly, in session three they tended to place the object closer to the incorrect location they recalled during day two rather than the correct location from day one.

"Our findings show that incorrect recollection of the object's location on day two influenced how people remembered the object's location on day three," Bridge explained. "Retrieving the memory didn't simply reinforce the original association. Rather, it altered memory storage to reinforce the location that was recalled at session two."

Bridge's findings also were supported when she measured participants' neural signals --the electrical activity of the brain -- during session two. She wanted to see if the neural signals during session two predicted anything about how people remembered the object's location during session three.

The results revealed a particular electrical signal when people were recalling an object location during session two. This signal was greater when -- the next day -- the object was placed close to that location recalled during session two. When the electrical signal was weaker, recall of the object location was likely to be less distorted.

"The strong signal seems to indicate that a new memory was being laid down," Bridge said, "and the new memory caused a bias to make the same mistake again."

"This study shows how memories normally change over time, sometimes becoming distorted," Paller noted. "When you think back to an event that happened to you long ago -- say your first day at school -- you actually may be recalling information you retrieved about that event at some later time, not the original event."

The research was supported by National Science Foundation grant BCS1025697 and National Institute of Neurological Disorders and Stroke of the National Institutes of Health grant T32 NS047987.

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The above story is reprinted from materials provided by Northwestern University. The original article was written by Marla Paul.

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Journal Reference:

1. D. J. Bridge, K. A. Paller. Neural Correlates of Reactivation and Retrieval-Induced Distortion. Journal of Neuroscience, 2012; 32 (35): 12144 DOI: 10.1523/JNEUROSCI.1378-12.2012

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Disclaimer: This article is not intended to provide medical advice, diagnosis or treatment. Views expressed here do not necessarily reflect those of ScienceDaily or its staff.

20 Sep, 2012

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Source: http://feeds.sciencedaily.com/~r/sciencedaily/top_news/top_science/~3/OALb1Y9nFG4/120919125736.htm
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Warming ocean could start big shift of Antarctic ice

ScienceDaily (Sep. 19, 2012) — Fast-flowing and narrow glaciers have the potential to trigger massive changes in the Antarctic ice sheet and contribute to rapid ice-sheet decay and sea-level rise, a new study has found.

Research results published in the journal Proceedings of the National Academy of Sciences reveal in more detail than ever before how warming waters in the Southern Ocean are connected intimately with the movement of massive ice-sheets deep in the Antarctic interior.

"It has long been known that narrow glaciers on the edge of the Antarctica act as discrete arteries termed ice streams, draining the interior of the ice sheet," says Dr Chris Fogwill, an author of the study and an ARC Future Fellow with the UNSW Climate Change Research Centre.

"However, our results have confirmed recent observations suggesting that ocean warming can trigger increased flow of ice through these narrow corridors. This can cause inland sectors of the ice-sheet -- some larger than the state of Victoria -- to become thinner and flow faster."

The researchers, led by Dr Nicholas Golledge from Victoria University of Wellington, New Zealand, tested high-resolution model simulations against reconstructions of the Antarctic ice sheet from 20,000 years ago, during the last glacial maximum.

They used a new model, capable of resolving responses to ice-streams and other fine- scale dynamic features that interact over the entire ice sheet. This had not previously been possible with existing models. They then used this data to analyze the effects of a warming ocean over time.

The results showed that while glacier acceleration triggered by ocean warming is relatively localized, the extent of the resultant ice-sheet thinning is far more widespread. This observation is particularly important in light of recently observed dynamic changes at the margins of Antarctica. It also highlighted areas that are more susceptible than others to changes in ocean temperatures.

The glaciers that responded most rapidly to warming oceans were found in the Weddell Sea, the Admundsen Sea, the central Ross Sea and in the Amery Trough.

The finding is important because of the enormous scale and potential impact the Antarctic ice sheets could have on sea-level rise if they shift rapidly, says Fogwill. "To get a sense of the scale, the Antarctic ice sheet is 3km deep -- three times the height of the Blue Mountains in many areas -- and it extends across an area that is equivalent to the distance between Perth and Sydney.

"Despite its potential impact, Antarctica's effect on future sea level was not fully included in the last IPCC report because there was insufficient information about the behavior of the ice sheet. This research changes that. This new, high-resolution modelling approach will be critical to improving future predictions of Antarctica's contribution to sea level over the coming century and beyond."

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The above story is reprinted from materials provided by University of New South Wales. The original article was written by Alvin Stone.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.

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Journal Reference:

1. N. R. Golledge, C. J. Fogwill, A. N. Mackintosh, K. M. Buckley. Dynamics of the last glacial maximum Antarctic ice-sheet and its response to ocean forcing. Proceedings of the National Academy of Sciences, 2012; DOI: 10.1073/pnas.1205385109

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19 Sep, 2012

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Source: http://feeds.sciencedaily.com/~r/sciencedaily/top_news/top_science/~3/vnrMPdEiEws/120919103610.htm
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Out of this world nanoscience: A computer chip that can assemble itself?

ScienceDaily (Sep. 19, 2012) — Imagine a computer chip that can assemble itself. According to Eric M. Furst, professor of chemical and biomolecular engineering at the University of Delaware, engineers and scientists are closer to making this and other scalable forms of nanotechnology a reality as a result of new milestones in using nanoparticles as building blocks in functional materials.

Furst and his postdoctoral researchers, James Swan and Paula Vasquez, along with colleagues at NASA, the European Space Agency, Zin Technologies and Lehigh University, reported the finding Sept. 17 in an article in the Proceedings of the National Academy of Sciences (PNAS) online edition.

The article details how the research team's exploration of colloids, microscopic particles that are mere hundredths the diameter of a human hair, to better understand how nano-"building blocks" can be directed to "self-assemble" into specific structures.

The research team studied paramagnetic colloids while periodically applying an external magnetic field at different intervals. With just the right frequency and field strength, the team was able to watch the particles transition from a random, solid like material into highly organized crystalline structures or lattices.

According to Furst, a professor in UD's Department of Chemical and Biomolecular Engineering, no one before has ever witnessed this guided "phase separation" of particles.

"This development is exciting because it provides insight into how researchers can build organized structures, crystals of particles, using directing fields and it may prompt new discoveries into how we can get materials to organize themselves," Furst said.

Because gravity plays a role in how the particles assemble or disassemble, the research team studied the suspensions aboard the International Space Station (ISS) through collaborative efforts with NASA scientists and astronauts. One interesting observation, Furst reported, was how the structure formed by the particles slowly coarsened, then rapidly grew and separated -- similar to the way oil and water separate when combined -- before realigning into a crystalline structure.

Already, Furst's lab has created novel nanomaterials for use in optical communications materials and thermal barrier coatings. This new detail, along with other recorded data about the process, will now enable scientists to discover other paths to manipulate and create new nanomaterials from nanoparticle building blocks.

"Now, when we have a particle that responds to an electric field, we can use these principles to guide that assembly into structures with useful properties, such as in photonics," Furst added.

The work could potentially prove important in manufacturing, where the ability to pre-program and direct the self-assembly of functional materials is highly desired.

"This is the first time we've presented the relationship between an initially disordered structure and a highly organized one and at least one of the paths between the two. We're excited because we believe the concept of directed self-assembly will enable a scalable form of nanotechnology," he said.

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The above story is reprinted from materials provided by University of Delaware. The original article was written by Karen B. Roberts.

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Journal Reference:

1. J. W. Swan, P. A. Vasquez, P. A. Whitson, E. M. Fincke, K. Wakata, S. H. Magnus, F. D. Winne, M. R. Barratt, J. H. Agui, R. D. Green, N. R. Hall, D. Y. Bohman, C. T. Bunnell, A. P. Gast, E. M. Furst. Multi-scale kinetics of a field-directed colloidal phase transition. Proceedings of the National Academy of Sciences, 2012; DOI: 10.1073/pnas.1206915109

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19 Sep, 2012

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Source: http://feeds.sciencedaily.com/~r/sciencedaily/top_news/top_science/~3/cZ0pJnEHsJ8/120919103138.htm
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Did a 'forgotten' meteor have a deadly, icy double-punch?

ScienceDaily (Sep. 19, 2012) — When a huge meteor collided with Earth about 2.5 million years ago and fell into the southern Pacific Ocean it not only could have generated a massive tsunami but also may have plunged the world into the Ice Ages, a new study suggests.

A team of Australian researchers says that because the Eltanin meteor -- which was up to two kilometres across -- crashed into deep water, most scientists have not adequately considered either its potential for immediate catastrophic impacts on coastlines around the Pacific rim or its capacity to destabilise the entire planet's climate system.

"This is the only known deep-ocean impact event on the planet and it's largely been forgotten because there's no obvious giant crater to investigate, as there would have been if it had hit a landmass," says Professor James Goff, lead author of a forthcoming paper in the Journal of Quaternary Science. Goff is co-director of UNSW's Australia-Pacific Tsunami Research Centre and Natural Hazards Research Laboratory.

"But consider that we're talking about something the size of a small mountain crashing at very high speed into very deep ocean, between Chile and Antarctica. Unlike a land impact, where the energy of the collision is largely absorbed locally, this would have generated an incredible splash with waves literally hundreds of metres high near the impact site.

"Some modelling suggests that the ensuing mega-tsunami could have been unimaginably large -- sweeping across vast areas of the Pacific and engulfing coastlines far inland. But it also would have ejected massive amounts of water vapour, sulphur and dust up into the stratosphere.

"The tsunami alone would have been devastating enough in the short term, but all that material shot so high into the atmosphere could have been enough to dim the sun and dramatically reduce surface temperatures. Earth was already in a gradual cooling phase, so this might have been enough to rapidly accelerate and accentuate the process and kick start the Ice Ages."

In the paper, Goff and colleagues from UNSW and the Australian Nuclear Science and Technology Organisation, note that geologists and climatologists have interpreted geological deposits in Chile, Antarctica, Australia, and elsewhere as evidence of climatic change, marking the start of the Quaternary period. An alternative interpretation is that some or all of these deposits may be the result of mega-tsunami inundation, the study suggests.

"There's no doubt the world was already cooling through the mid and late Pliocene," says co-author Professor Mike Archer. "What we're suggesting is that the Eltanin impact may have rammed this slow-moving change forward in an instant -- hurtling the world into the cycle of glaciations that characterized the next 2.5 million years and triggered our own evolution as a species.

"As a 'cene' changer -- that is, from the Pliocene to Pleistocene -- Eltanin may have been overall as significant as the meteor that took out the non-flying dinosaurs 65 million years ago. We're urging our colleagues to carefully reconsider conventional interpretations of the sediments we're flagging and consider whether these could be instead the result of a mega-tsunami triggered by a meteor."

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The above story is reprinted from materials provided by University of New South Wales. The original article was written by Bob Beale.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.

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Journal Reference:

1. James Goff, Catherine Chagué-Goff, Michael Archer, Dale Dominey-Howes, Chris Turney. The Eltanin asteroid impact: possible South Pacific palaeomegatsunami footprint and potential implications for the Pliocene-Pleistocene transition. Journal of Quaternary Science, 2012; DOI: 10.1002/jqs.2571

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19 Sep, 2012

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Source: http://feeds.sciencedaily.com/~r/sciencedaily/top_news/top_science/~3/W-AEZjbS5oc/120919103612.htm
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