Monday, January 11, 2010


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Astronomers using the W. M. Keck Observatory have peered far into a young planetary system, giving an unprecedented view of dust and gas that might eventually form worlds similar to Jupiter, Venus or even Earth.

“Because the gas, dust and debris that orbit young stars provide the raw materials for planets, probing the inner regions of those stars lets us learn about how Earth-like planets form,” said astronomer Sam Ragland of Keck Observatory. He and his collaborators recently measured the properties of a young planetary system at distances closer to the star than Venus is to the Sun.

The researchers used the Keck Interferometer, which combines the light-gathering power of both 10-meter Keck telescopes to act as an 85-meter telescope, much larger than any existing or planned telescope.

“Nothing else in the world provides us with the types of measurements the Keck Interferometer does,” said Wesley Traub of Caltech’s Jet Propulsion Laboratory. “In effect, it’s a zoom lens for the Keck telescopes.”

The “zoom lens” allowed the researchers to probe MWC 419, a blue, B-type star that has several times the mass of the Sun and lies about 2,100 light-years away in the constellation Cassiopeia. With an age less than ten million years, MWC 419 ranks as a stellar kindergartener.

With the interferometer and the increased ability to observe fine detail, the team measured temperatures in the planet-forming disk to within about 50 million miles of the star. “That’s about half of Earth’s distance from the Sun, and well within the orbit of Venus,” said team member William Danchi of NASA’s Goddard Space Flight Center in Greenbelt, Md.

For comparison, astronomers using a single telescope have directly observed HR 8799, Fomalhaut and GJ 758 and their orbiting planets, which are 40 to 100 times farther away from their stars.

The interferometry results were taken in near-infrared light (3.5 to 4.1 micrometers), which is a wavelength slightly longer than red light and is invisible to the human eye. The researchers used a newly implemented infrared camera, which is the only one of its kind on Earth, to make the first “L-band” interferometric observations of MWC 419.

“This unique infrared capability adds a new dimension to the Keck Interferometer in probing the density and temperature of planet-forming regions around young stars. This wavelength region is relatively unexplored,” Ragland said. “Basically, anything we see through this camera is brand new information.”

With the data, Ragland and his collaborators measured the temperature of dust at various regions throughout MWC 419’s inner disk. Temperature differences throughout the disk may indicate that the dust has different chemical compositions and physical properties that may affect how planets form. For example, in the Solar System, conditions were just right to allow rocky worlds to form closer to the Sun, while gas giants and icy moons assembled farther out in the system. The team reported their findings in the Sept. 20 issue of the Astrophysical Journal.

The observations are an “important first step” in a larger program to collect data on young stars that span the lower-mass T Tauri stars, which are the progenitors of Sun-like stars, to their more massive counterparts, like MWC 419, explained John Monnier, an interferometry scientist at the University of Michigan who was not involved with the study.

The astronomers want to study the range of developing stars because their mass, size and luminosity might affect the composition and physical characteristics of the surrounding disk. Ragland and his collaborators are continuing to collect data on young stars and will combine their infrared observations with new data from the Keck Interferometer’s “nulling” mode, a technique which will block out the light from the central star in a young planetary system.

(Photo: David A. Hardy)

W. M. Keck Observatory


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An international team of scientists led by researchers at The Scripps Research Institute has developed a straightforward technique to determine the ethnic origin of stem cells.

The Scripps Research scientists initiated the study—published in the January 2010 edition of the prestigious journal Nature Methods—because the availability of genetically diverse cell lines for cell replacement therapy and drug development could have important medical consequences. Research has shown that discordance between the ethnic origin of organ donors and recipients can influence medical outcomes for tissue transplantation, and that the safety and effectiveness of specific drugs can vary widely depending on ethnic background.

The team's analysis of a variety of human embryonic stem cell lines currently in use in research laboratories around the world found that these cells originated largely from Caucasian and East Asian populations, with little representation from populations originating in Africa. In response to these results, the scientists used skin cells from an individual of West African Yoruba heritage to create a new stem cell line, the first to carry the genetic profile of this ethnic group.

"Ethnic origin is a critical piece of information that should come with every cell line," said Scripps Research Professor Jeanne Loring, Ph.D., who is senior author of the paper. "Everyone who works with stem cells should be doing this kind of analysis."

"Knowing that a big push in the future is using these lines in the clinic and in drug development, there's a need to have an ethnically diverse population of cells," added Louise Laurent, M.D., Ph.D., assistant professor at the University of California, San Diego (UCSD) and research associate at Scripps Research, who is first author of the paper with Caroline Nievergelt, Ph.D., also an assistant professor at UCSD.

Greater diversity in cell samples would set the stage for more broadly relevant research by labs in academia and industry, more robust results on the safety and efficacy of potential therapies, and more successful tissue transplants.

Normally, cells develop from stem cells into a myriad of increasingly more specialized cell types during early development and throughout a lifetime. In humans and other mammals, these developmental events are usually irreversible. This means that when tissues are damaged or cells are lost, the body has limited means by which to replenish them.

Having a source of stem cells would be useful in many medical situations because these cells are "pluripotent," having the ability to become any of the body's cell types. Pluripotent stem cells would potentially provide physicians with the ability to replace or repair damaged tissues throughout the body. For example, pluripotent stem cells could be differentiated into the damaged cell type and transplanted.

Much research on pluripotent stem cells to date has been conducted on human embryonic stem cells, which are harvested from discarded embryos (those created but not used for the purposes of in vitro fertilization, a technique to help couples conceive). However, recently another source of pluripotent stem cells has come onto the scene. These cells—called induced pluripotent stem cells—are created by taking a sample of skin cells or another type of differentiated cell and using chemicals and molecular biology techniques to coax them back into a pluripotent state.

The current analysis included 47 human embryonic stem cell lines collected from labs located around the world—including Korea, Australia, and Finland. The analysis also included five induced pluripotent stem cell lines.

To determine the ethnic origins of the stem cell lines and to link them to genetic "signatures" that might affect medical outcomes, the scientists drew on previous research from the International HapMap Project, published in the journal Nature in 2003. This research linked single-letter alterations in the genetic code—known as single nucleotide polymorphisms, or SNPs—with people of known ethnic origins. This data provided a way to identify the ethnic heritage of a donor of any cell.

Laurent noted that simply asking cell donors about their ethnic heritage does not provide accurate data. "There's often an ancestor from a different area who a person doesn't know about," she said.

The technology used for the new study, known as SNP genotyping, uses microarrays, which are easily available, inexpensive, and relatively straight forward for scientists to use.

When the Scripps Research scientists applied the technique to the embryonic stem cell lines, they found that Caucasians were especially well represented among the samples, followed by East Asians. Cells of some mixed heritage were also common. Notably lacking from the samples were cell lines representing African heritage.

In addition, the authors found that the country in which a cell line was generated did not necessarily predict the ethnicity of the donor.

In creating a new pluripotent stem cell line from an individual with a West African Yoruba background, the scientists generated a line that contains distinct genetic markers for disease risk and drug metabolism.

"There's not a lot of value in making a new pluripotent stem cell line now unless it has something new to offer," said Loring. "I think that increasing ethnicity and genetic diversity is an important reason for generating new lines."

The data generated by the study—which Loring describes as the foundation of a new database of human pluripotent stem cell genetic information—will be available for other researchers to access for studies on specific genes, stem cell transplantation, and other topics.

The Scripps Research Institute


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Over the past decade, researchers have developed a variety of reliable real-time and archival instruments to study sounds made or heard by marine mammals and fish. These new sensors are now being used in research, management, and conservation projects around the world, with some very important practical results. Among them is improved monitoring of endangered North Atlantic right whales in an effort to reduce ship strikes, a leading cause of their deaths.

“The tools available to both acquire and analyze passive acoustic data have undergone a revolutionary change over the last ten years, and have substantially increased our ability to collect acoustic information and use it as a functional management tool,” said Sofie Van Parijs, lead author and a bioacoustician at NOAA’s Northeast Fisheries Science Center laboratory in Woods Hole, Mass. “These tools have significantly improved monitoring of North Atlantic right whales and enhanced the efficacy of managing ship traffic to reduce ship strikes of whales through much of the western North Atlantic off the U.S. East Coast.”

Van Parijs is one of many researchers whose work is described this month in the journal Marine Ecology Progress Series. Her paper is one of about a dozen in a special theme issue focused on acoustics in marine ecology. Van Parijs, who currently heads the NEFSC's Protected Species Branch, is also a co-author of a related paper on acoustic interference or masking, in which marine animals alter their use of sound as a result of changing background noise.

Van Parijs and her colleagues focus on two types of acoustic sensors, real-time and archival. Real-time sensors are mounted on surface buoys, usually anchored or cabled to the ocean bottom, or deployed as arrays towed from a surface vessel. Archival sensors are affixed on bottom-moored buoys equipped with hydrophones to continuously record ocean sounds for long periods of time, often up to three months, before the sensors are temporarily recovered and their batteries refreshed. Some archiving sensors can be mounted of individual animals.

“Marine animals live their lives and communicate acoustically across different time and space scales and use sound for different reasons,” said Van Parijs. “We need to use the right tool in the right place for the right need. There is no ‘one size fits all’ when it comes to using technology in the ocean.”

Large whales move and communicate over great distances, while smaller whales and dolphins tend to communicate over smaller areas. Pinnipeds, the group of marine mammals that includes seals, walrus and sea lions, can breed on land, on ice or in the water, and move and communicate from small to medium distances. Human-produced sounds complicate the sensing problem by adding sounds to what can be a very noisy environment.

The use of passive acoustic monitoring is increasing as improved reliability and lower hardware and software costs provide researchers with a set of tools that can answer a broad range of scientific questions. This information can, in turn, be used in conservation management and mitigation efforts. While most of the new technologies have been applied in studies of whales and dolphins, the researchers say the sensors can also be used in studying pinnipeds, sirenians (manatees and dugongs), and fish.

(Photo: Denise Risch, NEFSC/NOAA)

National Oceanic and Atmospheric Administration


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We see the popular "captcha" security mechanism often — wavy letters websites ask us to type into a box. It's used by web pages and newsletter sign-up forms to prevent computer robots from hacking into servers and databases. But these codes, which are becoming increasingly complicated for an average person to use, are not immune to security holes.

A research project led by Prof. Danny Cohen-Or of Tel Aviv University's Blavatnik School of Computer Sciences demonstrates how a new kind of video captcha code may be harder to outsmart. The foundation of the work, presented at a recent SIGGRAPH conference, is really pure research, says Prof. Cohen-Or, but it opens the door so security researchers can think a little differently.

"Humans have a very special skill that computer bots have not yet been able to master," says Prof. Cohen-Or. "We can see what's called an 'emergence image' — an object on a computer screen that becomes recognizable only when it's moving — and identify this image in a matter of seconds. While a person can't 'see' the image as a stationary object on a mottled background, it becomes part of our gestalt as it moves, allowing us to recognize and process it."

In the new research paper, co-authored with colleagues in Taiwan, Saudi Arabia and India, Prof. Cohen-Or describes a synthesis technique that generates pictures of 3-D objects, like a running man or a flying airplane. This technique, he says, will allow security developers to generate an infinite number of moving "emergence" images that will be virtually impossible for any computer algorithm to decode.

"Emergence," as defined by the researchers, is a unique human ability to collect fragments of seemingly useless information, then synthesize and perceive it as an identifiable whole. So far, computers don't have this skill. "Computer vision algorithms are completely incapable of effectively processing emergence images," says Prof. Cohen-Or's faculty colleague Dr. Lior Wolf, a co-author of the study.

The scientists warn that it will take some time before this research can be applied in the real world, but they are currently defining parameters that identify the "perception difficulty level" of various images that might be used in future security technologies.

"We're not claiming in our research paper that we've developed a whole new captcha technology," says Prof. Cohen-Or. "But we are taking a step towards that — something that could lead to a much better captcha, to highlight the big difference between men and bots. If it were to be turned into a solution, however, we wouldn't be able to give humans a multiple choice answer or common word answer for what they see, so we'll need to develop a way to use it. We have a few ideas in the works."

The researchers are also developing methods of automatically generating "hidden" images in a natural background, like a pastoral mountain setting — a digital "Where's Waldo?" game. "We're trying to hide images like eagles or a lion in mountainscape," says Prof. Cohen-Or. Because the moving image blends into a static background, it's hard for bots to understand what the human eye perceives with only minimal training.

"This could be a tough thing for a robot to crack, so we're working hard to make it practical," he emphasizes. "A good captcha has to be something that's easy for people but hard for a machine."

(Photo: TAU)

American Friends of Tel Aviv University


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2009 may well be remembered for its scandal-ridden headlines, from admissions of extramarital affairs by governors and senators, to corporate executives flying private jets while cutting employee benefits, and most recently, to a mysterious early morning car crash in Florida. The past year has been marked by a series of moral transgressions by powerful figures in political, business and celebrity circles. New research from the Kellogg School of Management at Northwestern University explores why powerful people - many of whom take a moral high ground - don't practice what they preach.

In "Power Increases Hypocrisy: Moralizing in Reasoning, Immunity and Behavior," researchers sought to determine whether power inspires hypocrisy, the tendency to hold high standards for others while performing morally suspect behaviors oneself. The research finds that power makes people stricter in moral judgment of others - while being less strict of their own behavior.

The research was conducted by Joris Lammers and Diederik A. Stapel of Tilburg University in the Netherlands, and by Adam Galinsky of the Kellogg School of Management at Northwestern University in Evanston, Ill. The article will appear in a forthcoming issue of Psychological Science.

"This research is especially relevant to the biggest scandals of 2009, as we look back on how private behavior often contradicted the public stance of particular individuals in power," said Galinsky, the Morris and Alice Kaplan Professor of Ethics and Decision in Management at the Kellogg School. "For instance, we saw some politicians use public funds for private benefits while calling for smaller government, or have extramarital affairs while advocating family values. Similarly, we witnessed CEOs of major financial institutions accepting executive bonuses while simultaneously asking for government bailout money on behalf of their companies."

"According to our research, power and influence can cause a severe disconnect between public judgment and private behavior, and as a result, the powerful are stricter in their judgment of others while being more lenient toward their own actions," he continued.

To simulate an experience of power, the researchers assigned roles of high-power and low-power positions to a group of study participants. Some were assigned the role of prime minister and others civil servant. The participants were then presented with moral dilemmas related to breaking traffic rules, declaring taxes, and returning a stolen bike.

Through a series of five experiments, the researchers examined the impact of power on moral hypocrisy. For example, in one experiment the "powerful" participants condemned the cheating of others while cheating more themselves. High-power participants also tended to condemn over-reporting of travel expenses. But, when given a chance to cheat on a dice game to win lottery tickets (played alone in the privacy of a cubicle), the powerful people reported winning a higher amount of lottery tickets than did low-power participants.

Three additional experiments further examined the degree to which powerful people accept their own moral transgressions versus those committed by others. In all cases, those assigned to high-power roles showed significant moral hypocrisy by more strictly judging others for speeding, dodging taxes and keeping a stolen bike, while finding it more acceptable to engage in these behaviors themselves.

Galinsky noted that moral hypocrisy has its greatest impact among people who are legitimately powerful. In contrast, a fifth experiment demonstrated that people who don't feel personally entitled to their power are actually harder on themselves than they are on others, which is a phenomenon the researchers dubbed "hypercrisy." The tendency to be harder on the self than on others also characterized the powerless in multiple studies.

"Ultimately, patterns of hypocrisy and hypercrisy perpetuate social inequality. The powerful impose rules and restraints on others while disregarding these restraints for themselves, whereas the powerless collaborate in reproducing social inequality because they don't feel the same entitlement," Galinsky concluded.

Psychological Science


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Scientists documented evidence that the Arctic Ocean and Nordic Seas were too warm to support summer sea ice during the mid-Pliocene warm period (3.3 to 3 million years ago). This period is characterized by warm temperatures similar to those projected for the end of this century, and is used as an analog to understand future conditions.

The U.S. Geological Survey found that summer sea-surface temperatures in the Arctic were between 10 to 18°C (50 to 64°F) during the mid-Pliocene, while current temperatures are around or below 0°C (32°F).

Examining past climate conditions allows for a true understanding of how Earth’s climate system really functions. USGS research on the mid-Pliocene is the most comprehensive global reconstruction for any warm period. This will help refine climate models, which currently underestimate the rate of sea ice loss in the Arctic.

Loss of sea ice could have varied and extensive consequences, such as contributions to continued Arctic warming, accelerated coastal erosion due to increased wave activity, impacts to large predators (polar bears and seals) that depend on sea ice cover, intensified mid-latitude storm tracks and increased winter precipitation in western and southern Europe, and less rainfall in the American west.

“In looking back 3 million years, we see a very different pattern of heat distribution than today with much warmer waters in the high latitudes,” said USGS scientist Marci Robinson. “The lack of summer sea ice during the mid-Pliocene suggests that the record-setting melting of Arctic sea ice over the past few years could be an early warning of more significant changes to come.”

Global average surface temperatures during the mid-Pliocene were about 3°C (5.5°F) greater than today and within the range projected for the 21st century by the Intergovernmental Panel on Climate Change.

U.S. Geological Survey




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