Wednesday, September 29, 2010


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Researchers are demonstrating that plants from Earth could be grown without soil on the moon or Mars, setting the table for astronauts who would find potatoes, peanuts, tomatoes, peppers and other vegetables awaiting their arrival.

The first extraterrestrials to inhabit the moon probably won't be little green men, but they could be little green plants.

Researchers at the University of Arizona Controlled Environment Agriculture Center, known as CEAC, are demonstrating that plants from Earth could be grown hydroponically (without soil) on the moon or Mars, setting the table for astronauts who would find potatoes, peanuts, tomatoes, peppers and other vegetables awaiting their arrival.

The research team has built a prototype lunar greenhouse in the CEAC Extreme Climate Lab at UA's Campus Agricultural Center. It represents the last 18 feet of one of several tubular structures that would be part of a proposed lunar base. The tubes would be buried beneath the moon's surface to protect the plants and astronauts from deadly solar flares, micrometeorites and cosmic rays.

The membrane-covered module can be collapsed to a 4-foot-wide disk for interplanetary travel. It contains water-cooled sodium vapor lamps and long envelopes that would be loaded with seeds, ready to sprout hydroponically.

"We can deploy the module and have the water flowing to the lamps in just ten minutes," said Phil Sadler, president of Sadler Machine Co., which designed and built the lunar greenhouse. "About 30 days later, you have vegetables."

Standing beside the growth chamber, which was overflowing with greenery despite the windowless CEAC lab, principal investigator and CEAC Director Gene Giacomelli said, "You can think of this as a robotic mechanism that is providing food, oxygen and fresh drinking water."

Giacomelli, a professor of agricultural and biosystems engineering and a member of the UA's BIO5 Institute, said that although this robot is built around living green plants – instead of the carbon fiber or steel usually associated with engineering devices – it still requires all the components common to any autonomous robotic system.

These components, which include sensors that gather data, algorithms to analyze that data and a control system to optimize performance, are being designed by assistant professor Roberto Furfaro of systems and industrial engineering, and associate professor Murat Kacira of agricultural and biosystems engineering.

"We want the system to operate itself," Kacira said. "However, we're also trying to devise a remote decision-support system that would allow an operator on Earth to intervene. The system can build its own analysis and predictions, but we want to have access to the data and the control system."

This is similar to the way a CEAC food-production system has been operating at the South Pole for the past six years.

The South Pole Growth Chamber, where many ideas now used in the lunar greenhouse were developed, was also designed and fabricated by Sadler Machine Co. It provides fresh food to the South Pole research station, which is physically cut off from the outside world for six to eight months each year.

In addition to food, the growth chamber provides a valuable psychological boost for scientists who overwinter at the station.

"There's only 5 percent humidity and all you can normally smell is diesel fuel and body odor," Sadler said. But now researchers can go into the growth chamber and smell vegetables and flowers and see living green things, breaking the monotony of thousands of square miles of ice and snow surrounding their completely man-made environment.

Lane Patterson, a master's student in agricultural and biosystems engineering and primary systems operations manager of CEAC's lunar greenhouse lab, also works for Raytheon Polar Services, which provides operations support for the South Pole Growth Chamber.

"If I need to be there in the chamber looking over an operator's shoulder, that's possible with the web camera," Patterson explained. "But if I need to make an adjustment to the chamber without the operator's assistance, I can do that electronically via computer communication."

Recycling and efficient use of resources are just as important to the South Pole operation as they will be on the moon, Sadler noted. A dozen 1,000-watt sodium-vapor lights generate a lot of heat, which is siphoned away by each lamp's cooling system and used to heat the station. "Energy is expensive there," Sadler said. "It's about $35 a gallon for diesel fuel."

In fact, efficient use of resources is just as important for hydroponic greenhouses anywhere on the globe, Giacomelli emphasized. "All that we learn from the life support system in the prototype lunar greenhouse can be applied right here on Earth," he added.

"On another planet, you need to minimize your labor, recycle all you can and operate as efficiently as possible," he said. "If I ask the manager of a hydroponic greenhouse in Willcox [Ariz.] what's most important, he or she will tell me those same things – recycle, minimize labor, minimize resource use."

Carbon dioxide is fed into the prototype greenhouse from pressurized tanks, but astronauts would provide CO2 at the lunar base just by breathing. Similarly, water for the plants would be extracted from astronaut urine, and the water-cooled electric lights might be replaced by fiber optic cable – essentially light pipes – which would channel sunlight from the surface to the plants underground.

The lunar greenhouse contains approximately 220 pounds of wet plant material that can provide 53 quarts of potable water and about three-quarters of a pound of oxygen during a 24-hour period, while consuming about 100 kilowatts of electricity and a pound of carbon dioxide.

"We turned the greenhouse on about eight months ago to see how it would operate and that test run will be completed on Sept. 30," Giacomelli said.

NASA is funding that research under a $70,000 Ralph Steckler Space Grant Colonization Research and Technology Development Opportunity, which CEAC obtained with help from UA's Lunar and Planetary Laboratory. The Steckler grants are designed to support research that could lead to space colonization, a better understanding of the lunar environment and creation of technologies that will support space colonies.

CEAC now is applying for Phase II of this grant, which would provide an additional $225,000 for two years.

Although NASA funds the test run, "everything you see in this room – the greenhouse module, lights, water system – came out of Phil Sadler's pocket," Giacomelli said. "I paid for the student help and pay the bills for the research space. Obviously, we think this is important work."

The UA researchers and Sadler Machine also are collaborating with two Italian firms on this project: Thales Alenia Space, a company that builds hardware for the International Space Station, and Aero Sekur, which builds inflatable structures.

Giacomelli said the research also could lead to plant colonization in another traditionally hostile environment – large urban centers.

"There's great interest in providing locally grown, fresh food in cities, for growing food right where masses of people are living," Giacomelli said. "It's the idea of growing high-quality fresh food that only has to be transported very short distances. There also would be a sense of agriculture returning to the everyday lives of urban dwellers."

"I think that idea is as exciting as establishing plant colonies on the moon."

(Photo: Norma Jean Gargasz / UANews)

University of Arizona


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Engineers at UC Berkeley have developed a pressure-sensitive electronic material from semiconductor nanowires that could one day give new meaning to the term "thin-skinned."

"The idea is to have a material that functions like the human skin, which means incorporating the ability to feel and touch objects," said Ali Javey, associate professor of electrical engineering and computer sciences and head of the UC Berkeley research team developing the artificial skin.

The artificial skin, dubbed "e-skin" by the UC Berkeley researchers, is described in a Sept. 12 paper in the advanced online publication of the journal Nature Materials. It is the first such material made out of inorganic single crystalline semiconductors.

A touch-sensitive artificial skin would help overcome a key challenge in robotics: adapting the amount of force needed to hold and manipulate a wide range of objects.

"Humans generally know how to hold a fragile egg without breaking it," said Javey, who is also a member of the Berkeley Sensor and Actuator Center and a faculty scientist at the Lawrence Berkeley National Laboratory Materials Sciences Division. "If we ever wanted a robot that could unload the dishes, for instance, we’d want to make sure it doesn’t break the wine glasses in the process. But we’d also want the robot to be able to grip a stock pot without dropping it."

A longer term goal would be to use the e-skin to restore the sense of touch to patients with prosthetic limbs, which would require significant advances in the integration of electronic sensors with the human nervous system.

Previous attempts to develop an artificial skin relied upon organic materials because they are flexible and easier to process.

"The problem is that organic materials are poor semiconductors, which means electronic devices made out of them would often require high voltages to operate the circuitry," said Javey. "Inorganic materials, such as crystalline silicon, on the other hand, have excellent electrical properties and can operate on low power. They are also more chemically stable. But historically, they have been inflexible and easy to crack. In this regard, works by various groups, including ours, have recently shown that miniaturized strips or wires of inorganics can be made highly flexible — ideal for high performance, mechanically bendable electronics and sensors."

The UC Berkeley engineers utilized an innovative fabrication technique that works somewhat like a lint roller in reverse. Instead of picking up fibers, nanowire "hairs" are deposited.

The researchers started by growing the germanium/silicon nanowires on a cylindrical drum, which was then rolled onto a sticky substrate. The substrate used was a polyimide film, but the researchers said the technique can work with a variety of materials, including other plastics, paper or glass. As the drum rolled, the nanowires were deposited, or “printed,” onto the substrate in an orderly fashion, forming the basis from which thin, flexible sheets of electronic materials could be built.

In another complementary approach utilized by the researchers, the nanowires were first grown on a flat source substrate, and then transferred to the polyimide film by a direction-rubbing process.

For the e-skin, the engineers printed the nanowires onto an 18-by-19 pixel square matrix measuring 7 centimeters on each side. Each pixel contained a transistor made up of hundreds of semiconductor nanowires. Nanowire transistors were then integrated with a pressure sensitive rubber on top to provide the sensing functionality. The matrix required less than 5 volts of power to operate and maintained its robustness after being subjected to more than 2,000 bending cycles.

The researchers demonstrated the ability of the e-skin to detect pressure from 0 to 15 kilopascals, a range comparable to the force used for such daily activities as typing on a keyboard or holding an object. In a nod to their home institution, the researchers successfully mapped out the letter C in Cal.

"This is the first truly macroscale integration of ordered nanowire materials for a functional system — in this case, an electronic skin," said study lead author Kuniharu Takei, post-doctoral fellow in electrical engineering and computer sciences. "It’s a technique that can be potentially scaled up. The limit now to the size of the e-skin we developed is the size of the processing tools we are using."

(Photo: Ali Javey and Kuniharu Takei, UC Berkeley)

University of California, Berkeley


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Want to know how a Japanese person is feeling? Pay attention to the tone of his voice, not his face. That’s what other Japanese people would do, anyway. A new study examines how Dutch and Japanese people assess others’ emotions and finds that Dutch people pay attention to the facial expression more than Japanese people do.

“As humans are social animals, it’s important for humans to understand the emotional state of other people to maintain good relationships,” says Akihiro Tanaka of Waseda Institute for Advanced Study in Japan. “When a man is smiling, probably he is happy, and when he is crying, probably he’s sad.” Most of the research on understanding the emotional state of others has been done on facial expression; Tanaka and his colleagues in Japan and the Netherlands wanted to know how vocal tone and facial expressions work together to give you a sense of someone else’s emotion.

For the study, Tanaka and colleagues made a video of actors saying a phrase with a neutral meaning—“Is that so?”—two ways: angrily and happily. This was done in both Japanese and Dutch. Then they edited the videos so that they also had recordings of someone saying the phrase angrily but with a happy face, and happily with an angry face. Volunteers watched the videos in their native language and in the other language and were asked whether the person was happy or angry. They found that Japanese participants paid attention to the voice more than Dutch people did—even when they were instructed to judge the emotion by the faces and to ignore the voice. The results are published in Psychological Science, a journal of the Association for Psychological Science.

This makes sense if you look at the differences between the way Dutch and Japanese people communicate, Tanaka speculates. “I think Japanese people tend to hide their negative emotions by smiling, but it’s more difficult to hide negative emotions in the voice.” Therefore, Japanese people may be used to listening for emotional cues. This could lead to confusion when a Dutch person, who is used to the voice and the face matching, talks with a Japanese person; they may see a smiling face and think everything is fine, while failing to notice the upset tone in the voice. “Our findings can contribute to better communication between different cultures,” Tanaka says.

Association for Psychological Science


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Behind every coincidence lies a plan - in the world of classical physics, at least. In principle, every event, including the fall of dice or the outcome of a game of roulette, can be explained in mathematical terms. Researchers at the Max Planck Institute for the Science of Light in Erlangen have constructed a device that works on the principle of true randomness. With the help of quantum physics, their machine generates random numbers that cannot be predicted in advance. The researchers exploit the fact that measurements based on quantum physics can only produce a special result with a certain degree of probability, that is, randomly. True random numbers are needed for the secure encryption of data and to enable the reliable simulation of economic processes and changes in the climate.

The phenomenon we commonly refer to as chance is merely a question of a lack of knowledge. If we knew the location, speed and other classical characteristics of all of the particles in the universe with absolute certainty, we would be able to predict almost all processes in the world of everyday experience. It would even be possible to predict the outcome of a puzzle or lottery numbers. Even if they are designed for this purpose, the results provided by computer programs are far from random: "They merely simulate randomness but with the help of suitable tests and a sufficient volume of data, a pattern can usually be identified," says Christoph Marquardt. In response to this problem, a group of researchers working with Gerd Leuchs and Christoph Marquardt at the Max Planck Institute for the Science of Light and the University of Erlangen-Nuremberg and Ulrik Andersen from the Technical University of Denmark have developed a generator for true random numbers.

True randomness only exists in the world of quantum mechanics. A quantum particle will remain in one place or another and move at one speed or another with a certain degree of probability. "We exploit this randomness of quantum-mechanical processes to generate random numbers," says Christoph Marquardt.

The scientists use vacuum fluctuations as quantum dice. Such fluctuations are another characteristic of the quantum world: there is nothing that does not exist there. Even in absolute darkness, the energy of a half photon is available and, although it remains invisible, it leaves tracks that are detectable in sophisticated measurements: these tracks take the form of quantum noise. This completely random noise only arises when the physicists look for it, that is, when they carry out a measurement.

To make the quantum noise visible, the scientists resorted once again to the quantum physics box of tricks: they split a strong laser beam into equal parts using a beam splitter. A beam splitter has two input and output ports. The researchers covered the second input port to block light from entering. The vacuum fluctuations were still there, however, and they influenced the two partial output beams. The physicists then send them to the detectors and measure the intensity of the photon stream. Each photon produces an electron and the resulting electrical current is registered by the detector.

When the scientists subtract the measurement curves produced by the two detectors from each other, they are not left with nothing. What remains is the quantum noise. "During measurement the quantum-mechanical wave function is converted into a measured value," says Christian Gabriel, who carried out the experiment with the random generator with his colleagues at the Max Planck Institute in Erlangen: "The statistics are predefined but the intensity measured remains a matter of pure chance." When plotted in a Gaussian bell-shaped curve, the weakest values arise frequently while the strongest occur rarely. The researchers divided the bell-shaped curve of the intensity spread into sections with areas of equal size and assigned a number to each section.

Needless to say, the researchers did not decipher this quantum mechanics puzzle to pass the time during their coffee breaks. "True random numbers are difficult to generate but they are needed for a lot of applications," says Gerd Leuchs, Director of the Max Planck Institute for the Science of Light in Erlangen. Security technology, in particular, needs random combinations of numbers to encode bank data for transfer. Random numbers can also be used to simulate complex processes whose outcome depends on probabilities. For example, economists use such Monte Carlo simulations to predict market developments and meteorologists use them to model changes in the weather and climate.

There is a good reason why the Erlangen-based physicists chose to produce the random numbers using highly complex vacuum fluctuations rather than other random quantum processes. When physicists observe the velocity distribution of electrons or the quantum noise of a laser, for example, the random quantum noise is usually superimposed by classical noise, which is not random. "When we want to measure the quantum noise of a laser beam, we also observe classical noise that originates, for example, from a shaking mirror," says Christoffer Wittmann who also worked on the experiment. In principle, the vibration of the mirror can be calculated as a classical physical process and therefore destroys the random game of chance.

"Admittedly, we also get a certain amount of classical noise from the measurement electronics," says Wolfgang Mauerer who studied this aspect of the experiment. "But we know our system very well and can calculate this noise very accurately and remove it." Not only can the quantum fluctuations enable the physicists to eavesdrop on the pure quantum noise, no one else can listen in. "The vacuum fluctuations provide unique random numbers," says Christoph Marquardt. With other quantum processes, this proof is more difficult to provide and the danger arises that a data spy will obtain a copy of the numbers. "This is precisely what we want to avoid in the case of random numbers for data keys," says Marquardt.

Although the quantum dice are based on mysterious phenomena from the quantum world that are entirely counterintuitive to everyday experience, the physicists do not require particularly sophisticated equipment to observe them. The technical components of their random generator can be found among the basic equipment used in many laser laboratories. "We do not need either a particularly good laser or particularly expensive detectors for the set-up," explains Christian Gabriel. This is, no doubt, one of the reasons why companies have already expressed interest in acquiring this technology for commercial use.

(Photo: MPI for the Physics of Light)

Max Planck Institute


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It seems the old nature versus nurture debate can’t be won. But a new Northwestern University study of men in the Philippines makes a strong case for nurture’s role in male to female differences -- suggesting that rapid weight gain in the first six months of life predicts earlier puberty for boys.

Males who experienced rapid growth as babies -- an indication that they were not nutritionally stressed -- also were taller, had more muscle and were stronger, and had higher testosterone levels as young adults. They had sex for the first time at a younger age and were more likely to report having had sex in the past month, resulting in more lifetime sex partners.

The researchers think that testosterone may hold the key to understanding these long-term effects.

“Most people are unaware that male infants in the first six months of life produce testosterone at approximately the same level as an adult male,” said study author Christopher W. Kuzawa, associate professor of anthropology in the Weinberg College of Arts and Sciences and Institute for Policy Research fellow at Northwestern. “We looked at weight gain during this particular window of early life development, because testosterone is very high at this age and helps shape the differences between males and females.”

The study provides more evidence that genes alone do not shape our fate.

“The environment has a very strong hand in how we turn out,” Kuzawa said. “And this study extends that idea to the realm of sex differences and male biology.”

The study found men, on average, tend to be taller and more muscular than females, and the magnitude of that difference appears to be the result of nutrition within the first six months of an infant male’s life, according to the study.

“There is a perennial question about how important heredity is versus the environment as shapers of who we turn out to be,” said Kuzawa. “In the last 20 years, a lot has been learned about a process called developmental plasticity -- how the body responds early in life to things like nutrition and stress. Early experiences can have a permanent effect on how the body develops, and this effect can linger into adulthood. There is a lot of evidence that this can influence risk of diseases like heart attack, diabetes and hypertension -- really important diseases.”

Kuzawa and his collaborators applied the same framework in this study and found evidence that male characteristics -- such as height, muscle mass and testosterone levels as opposed to disease characteristics -- also relate back to early life developmental plasticity.

“Another way to look at it is that the differences between the sexes are not hard wired, but are responsive to the environment, and in particular to nutrition,” Kuzawa said.

Testosterone has long been known to increase muscle mass and puts a person on a higher growth trajectory to be taller. The Northwestern study suggests that the age of puberty also is influenced by events in the first six months of life.

The study, which was funded by the National Science Foundation and the Wenner Gren Foundation, was conducted among a group of 770 Filipino males aged 20 to 22 who have been followed their entire lives. Since 1983 a team of researchers in the United States and the Philippines (including Kuzawa for about the last 10 years) has been working to understand how early life nutrition influences adult health, such as risk for cardiovascular disease and diabetes.

“Rapid Weight Gain After Birth Predicts Life History and Reproductive Strategy in Filipino Males” was published Sept. 13 in the Proceedings of the National Academy of Sciences. The study’s co-authors are Thomas W. McDade, associate professor of anthropology and Institute for Policy Research fellow, Northwestern University, Linda S. Adair, University of North Carolina at Chapel Hill, and Nanette Lee, University of San Carlos of the Office of Population Studies in Cebu City, Philippines.

Northwestern University


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Our eyes are windows to the world, but what is the visual experience of infants? We know that infant vision tends to be blurrier than adults'. Now researchers from UC Davis, UC Berkeley and Stanford University have discovered that they also have much poorer peripheral vision.

Infants only perceive what they stare at, and they perceive a jumbled, tangled mass of features in their periphery," said Faraz Farzin, a postdoctoral researcher at Stanford University who conducted the work as a graduate student at the UC Davis Center for Mind and Brain.

At play is a phenomenon that brain scientists call "crowding," in which the clutter of images in the peripheral vision makes it difficult to recognize an individual object. Adults also suffer from crowding, but much less than infants, Farzin said.

The results were published online this month in the journal Psychological Science.

Farzin and co-authors Susan Rivera, associate professor at the UC Davis Department of Psychology, Center for Mind and Brain and the MIND Institute; and David Whitney, associate professor of psychology at UC Berkeley and a research associate at the Center for Mind and Brain, used eye-tracking to find what babies will turn their eyes to look at in their periphery.

They showed the infants, six to 15 months of age, pairs of images of faces, one upright and one upside-down, with or without flanking images around them. The infants could discriminate the upright face in their peripheral vision, but not when it was crowded by flanking images, they found.

The finding has both theoretical and practical value, Farzin said.

"Identifying and reaching for a specific toy in a pile is no easy feat for a baby," she said. Knowing the visual limits of a typically developing baby also helps psychologists to identify when visual development is lagging.

The study was supported by grants from the National Institutes of Health and the National Science Foundation.

University of California, Davis




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