Coursera makes top college courses free online

Coursera makes top college courses free online

  8:53:00 AM    Science Lover

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Daphne Koller and Andrew Ng share a vision in which anyone, no matter how destitute, can expand their minds and prospects with lessons from the world's top universities.

Coursera co-founders Andrew Ng and Daphne Koller

That dream was joined this week by a dozen vaunted academic institutions including Duke University, the Ecole Polytechnique Federale de Lausanne (EPFL) in Switzerland and the University of Edinburgh in Scotland.

The schools will add online versions of classes to Coursera.org, a website launched by Stanford University professors Koller and Ng early this year with debut offerings from Princeton, Stanford and two other US universities.

"We have a vision where students everywhere around the world, regardless of country, family circumstances or financial circle have access to top quality education whether to expand their minds or learn valuable skills," Koller said.

"Where education becomes a right, not a privilege."

Academic institutions are increasingly turning to the Internet as an educational platform. A Khan Academy website created by Massachusetts Institute of Technology (MIT) graduate Salman Khan provides thousands of video lectures.

The nonprofit behind prestigious TED gatherings recently launched a TED-Ed channel at YouTube that teams accomplished teachers with talented animators to make videos that captivate while they educate.

In May, Harvard University and MIT announced that they were teaming up to expand their online education programs -- and invited other institutions to jump on board.

Called edX, the $60 million joint venture builds on MIT's existing MITx platform that enables video lesson segments, embedded quizzes, immediate feedback, online laboratories and student-paced learning.

"Universities have come to realize that online is not a fad," Koller said. "The question is not whether to engage in this area but how to do it."

Coursera classes are free, and completion certificates are issued that people can use to win jobs or improve careers.

"If a student takes a Stanford computer class and a Princeton business class, it shows they are motivated and have skills," Koller said. "We know it has helped employees get better jobs."

Coursera is distinguishing itself with essentially virtual versions of real classes.

"A lot of what is out there is basically video with, perhaps, some static content like lecture notes," Koller said.

"We are providing an actual course exchange were people register and there is weekly homework that is graded with feedback about how they are doing."

Coursera classes launched in February with most of the courses slated to begin in the coming months but it has already attracted students in 190 countries, according to Koller.

Coursera uses crowd-sourcing to translate material into various languages and hopes to connect with French-speaking populations around the world with EPFL classes.

Hoping to spread knowledge around the world, Coursera is a way to inspire faculty to try new methods of teaching and find ways that Internet Age tools can enhance on-campus courses, according to Duke provost Peter Lange.

"Our faculty is incredibly excited by the idea of trying it out and seeing if we can learn from it," Lange said.

"I love the idealism of it; the potential to reach people who might never get the chance to attend the university."

Duke designs its online courses to get students involved, complete with social networking tools for collaborating outside of classes.

"This is a great experiment in innovation and learning," Lange said.

As of Friday, Coursera boasted about 740,000 students and that number is expected to soar as word spreads and class offerings expand.

Coursera plans to keep classes free but perhaps one day make money for operations by charging for course completion certificates or matching employers with qualified workers.

"Current ethos in Silicon Valley is that if you build a website that people keep coming back to and is changing the lives of millions, you can eventually make money," Koller said.

"If and when we develop revenue, universities will share in it."

Paying the bills is not a worry at Coursera due to generous backing that includes a $3.7 million combined investment by the University of Pennsylvania and the California Institute of Technology, as well as funding from venture capital powerhouse Kleiner Perkins Caufield & Byers.

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Solar Cells that See Red

Solar Cells that See Red

  10:25:00 AM    Science Lover

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Metamaterials that convert lower-energy photons to usable wavelengths could offer solar cells an efficiency boost.

Light switch: In a process that could make
solar cells more efficient, green laser light
is "upconverted" to blue light by a
solution of dyes and metal nanoparticles.
Credit: Jennifer Dionne

Researchers at Stanford University have demonstrated a set of materials that could enable solar cells to use a band of the solar spectrum that otherwise goes to waste. The materials layered on the back of solar cells would convert red and near-infrared light—unusable by today's solar cells—into shorter-wavelength light that the cells can turn into energy. The university researchers will collaborate with the Bosch Research and Technology Center in Palo Alto, California, to demonstrate a system in working solar cells in the next four years.

Even the best of today's silicon solar cells can't use about 30 percent of the light from the sun: that's because the active materials in solar cells can't interact with photons whose energy is too low. But though each of these individual photons is low energy, as a whole they represent a large amount of untapped solar energy that could make solar cells more cost-competitive.

The process, called "upconversion," relies on pairs of dyes that absorb photons of a given wavelength and re-emit them as fewer, shorter-wavelength photons. In this case, the Bosch and Stanford researchers will work on systems that convert near-infrared wavelengths (most of which are unusable by today's solar cells). The leader of the Stanford group, assistant professor Jennifer Dionne, believes the group can improve the sunlight-to-electricity conversion efficiency of amorphous-silicon solar cells from 11 percent to 15 percent.



The concept of upconversion isn't new, but it's never been demonstrated in a working solar cell, says Inna Kozinsky, a senior engineer at Bosch. Upconversion typically requires two types of molecules to absorb relatively high-wavelength photons, combine their energy, and re-emit it as higher-energy, lower-wavelength photons. However, the chances of the molecules encountering each other at the right time when they're in the right energetic states are low. Dionne is developing nanoparticles to add to these systems in order to increase those chances. To make better upconversion systems, Dionne is designing metal nanoparticles that act like tiny optical antennas, directing light in these dye systems in such a way that the dyes are exposed to more light at the right time, which creates more upconverted light, and then directing more of that upconverted light out of the system in the end.

The ultimate vision, says Dionne, is to create a solid. Sheets of such a material could be laid down on the bottom of the cell, separated from the cell itself by an electrically insulating layer. Low-wavelength photons that pass through the active layer would be absorbed by the upconverter layer, then re-emitted back into the active layer as usable, higher-wavelength light.

Kozinsky says Bosch's goal is to demonstrate upconversion of red light in working solar cells in three years, and upconversion of infrared light in four years. Factoring in the time needed to scale up to manufacturing, she says, the technology could be in Bosch's commercial solar cells in seven to 10 years.

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Feelings of Love: Effective Pain Relief

Feelings of Love: Effective Pain Relief

  5:52:00 PM    Science Lover

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Intense, passionate feelings of love can provide amazingly effective pain relief, similar to painkillers or such illicit drugs as cocaine, according to a new Stanford University School of Medicine study.

Love-induced pain relief was associated with the activation of primitive brain structures that control rewarding experiences, such as the nucleus accumbens – shown here in color. (Credit: Courtesy of Sean Mackey and Jarred Younger)

"When people are in this passionate, all-consuming phase of love, there are significant alterations in their mood that are impacting their experience of pain," said Sean Mackey, MD, PhD, chief of the Division of Pain Management, associate professor of anesthesia and senior author of the study, which will be published online Oct. 13 in PLoS ONE. "We're beginning to tease apart some of these reward systems in the brain and how they influence pain. These are very deep, old systems in our brain that involve dopamine -- a primary neurotransmitter that influences mood, reward and motivation."

Scientists aren't quite yet ready to tell patients with chronic pain to throw out the painkillers and replace them with a passionate love affair; rather, the hope is that a better understanding of these neural-rewards pathways that get triggered by love could lead to new methods for producing pain relief.

"It turns out that the areas of the brain activated by intense love are the same areas that drugs use to reduce pain," said Arthur Aron, PhD, a professor of psychology at State University of New York at Stony Brook and one of the study's authors. Aron has been studying love for 30 years. "When thinking about your beloved, there is intense activation in the reward area of the brain -- the same area that lights up when you take cocaine, the same area that lights up when you win a lot of money."

The concept for the study was sparked several years ago at a neuroscience conference when Aron, an expert in the study of love, met up with Mackey, an expert in the research of pain, and they began talking.

"Art was talking about love," Mackey said. "I was talking about pain. He was talking about the brain systems involved with love. I was talking about the brain systems involved with pain. We realized there was this tremendous overlapping system. We started wondering, 'Is it possible that the two modulate each other?'"

After the conference, Mackey returned to Stanford and collaborated with postdoctoral scholar Jarred Younger, PhD, now an assistant professor of anesthesia, who was also intrigued with the idea. Together the three set up a study that would entail examining the brain images of undergraduates who claimed to be "in that first phase of intense love."

"We posted fliers around Stanford University and within hours we had undergrads banging on our door," Mackey said. The fliers asked for couples who were in the first nine months of a romantic relationship.

"It was clearly the easiest study the pain center at Stanford has ever recruited for," Mackey said. "When you're in love you want to tell everybody about it.

"We intentionally focused on this early phase of passionate love," he added. "We specifically were not looking for longer-lasting, more mature phases of the relationship. We wanted subjects who were feeling euphoric, energetic, obsessively thinking about their beloved, craving their presence.

"When passionate love is described like this, it in some ways sounds like an addiction. We thought, 'Maybe this does involve similar brain systems as those involved in addictions which are heavily dopamine-related.' Dopamine is the neurotransmitter in our brain that is intimately involved with feeling good."

Researchers recruited 15 undergraduates (eight women and seven men) for the study. Each was asked to bring in photos of their beloved and photos of an equally attractive acquaintance. The researchers then successively flashed the pictures before the subjects, while heating up a computer-controlled thermal stimulator placed in the palm of their hand to cause mild pain. At the same time, their brains were scanned in a functional magnetic resonance imaging machine.

The undergraduates were also tested for levels of pain relief while being distracted with word-association tasks such as: "Think of sports that don't involve balls." Scientific evidence has shown in the past that distraction causes pain relief, and researchers wanted to make sure that love was not just working as a distraction from pain.

Results showed that both love and distraction did equally reduce pain, and at much higher levels than by concentrating on the photo of the attractive acquaintance, but interestingly the two methods of pain reduction used very different brain pathways.

"With the distraction test, the brain pathways leading to pain relief were mostly cognitive," Younger said. "The reduction of pain was associated with higher, cortical parts of the brain. Love-induced analgesia is much more associated with the reward centers. It appears to involve more primitive aspects of the brain, activating deep structures that may block pain at a spinal level -- similar to how opioid analgesics work.

"One of the key sites for love-induced analgesia is the nucleus accumbens, a key reward addiction center for opioids, cocaine and other drugs of abuse. The region tells the brain that you really need to keep doing this," Younger said.

"This tells us that you don't have to just rely on drugs for pain relief," Aron said. "People are feeling intense rewards without the side effects of drugs."

Other Stanford contributors include research assistants Sara Parke and Neil Chatterjee.

Funding for the study was received from the Chris Redlich Pain Research Fund.

Editor's Note: This article is not intended to provide medical advice, diagnosis or treatment.

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A New Way to Use the Sun's Energy

A New Way to Use the Sun's Energy

  1:47:00 AM    Science Lover

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Researchers have demonstrated a new mechanism for converting both sunlight and heat into electricity.

A new type of device that uses both heat and light from the sun should be more efficient than conventional solar cells, which convert only the light into electricity.

Bright heat: Nicholas Melosh has
developed a device for simultaneously
converting the sun’s light and heat into
electricity. Melosh makes and tests the
device in this vacuum chamber in his
lab at Stanford University.
Credit: Technology Review

The device relies on a physical principle discovered and demonstrated by researchers at Stanford University. In their prototype, the energy in sunlight excites electrons in an electrode, and heat from the sun coaxes the excited electrons to jump across a vacuum into another electrode, generating an electrical current. The device could be designed to send waste heat to a steam engine and convert 50 percent of the energy in sunlight into electricity--a huge improvement over conventional solar cells.

The most common silicon solar cells convert about 15 percent of the energy in sunlight into electricity. More than half of the incoming solar energy is lost as heat. That's because the active materials in solar cells can interact with only a particular band of the solar spectrum; photons below a certain energy level simply heat up the cell.

One way to overcome this is to stack active materials on top of one another in a multijunction cell that can use a broader spectrum of light, turning more of it into electrical current instead of heat, for efficiencies up to about 40 percent. But such cells are complex and expensive to make.

Looking for a better way to take advantage of the sun's heat, Stanford's Nicholas Melosh was inspired by highly efficient cogeneration systems that use the expansion of burning gas to drive a turbine and the heat from the combustion to power a steam engine. But thermal energy converters don't pair well with conventional solar devices. The hotter it is, the more efficient thermal energy conversion becomes. Solar cells, by contrast, get less efficient as they heat up. At about 100 °C, a silicon cell won't work well; above 200 °C, it won't work at all.

The breakthrough came when the Stanford researchers realized that the light in solar radiation could enhance energy conversion in a different type of device, called a thermionic energy converter, that's conventionally driven solely by heat. Thermionic converters consist of two electrodes separated by a small space. When the positive electrode, or cathode, is heated, electrons in the cathode get excited and jump across to the negative electrode, or anode, driving a current through an external circuit. These devices have been used to power Russian satellites but haven't found any applications on the ground because they must get very hot, about 1,500 °C, to operate efficiently. The cathode in these devices is typically made of metals such as cesium.

Melosh's group replaced the cesium cathode with a wafer of semiconducting material that can make use of not only heat but also light. When light strikes the cathode, it transmits its energy to electrons in the material in a way that's similar to what happens in a solar cell. This type of energy transfer doesn't happen in the metals used to make these cathodes in the past, but it's typical of semiconductor materials. It doesn't take quite as much heat for these "preëxcited" electrons to jump to the anode, so this new device can operate at lower temperatures than conventional thermionic converters, but at higher temperatures than a solar cell.

The Stanford researchers call this new mechanism PETE, for photon-enhanced thermionic emission. "The light helps lift the energy level of the electrons so that they will flow," says Gang Chen, professor of power engineering at MIT. "It's a long way to a practical device, but this work shows that it's possible," he says.

The Stanford group's prototype, described this month in the journal Nature Materials, uses gallium nitride as the semiconductor. It converts just about 25 percent of the energy in light into electricity at 200 °C, and the efficiency rises with the temperature. Stuart Licht, professor of chemistry at George Washington University, says the process would have an "advantage over solar cells" because it makes use of heat in addition to light. But he cautions: "Additional work will be needed to translate this into a practical, more efficient device."

The Stanford group is now working to do just that. The researchers are testing devices made from materials that are better suited to solar energy conversion, including silicon and gallium arsenide. They're also developing ways of treating these materials so that the device will work more efficiently in a temperature range of 400 °C to 600 °C; solar concentrators would be used to generate such high temperatures from sunlight.

Even at high temperatures, the photon-enhanced thermionic converter will generate more heat than it can use; Melosh says this heat could be coupled to a steam engine for a solar-energy-to-electricity conversion efficiency exceeding 50 percent. These systems are likely to be too complex and expensive for small-scale rooftop installations. But they could be economical for large solar-farm installations, says Melosh, a professor of materials science and engineering. He hopes to have a device ready for commercial development in three years.

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Thermal-Powered, Insect-Like Robot Crawls Into Microrobot Contenders' Ring

Thermal-Powered, Insect-Like Robot Crawls Into Microrobot Contenders' Ring

  9:51:00 AM    Science Lover

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Robotic cars attracted attention last decade with a 100-mile driverless race across the desert competing for a $1 million prize put up by the U.S. government.

Tiny, four-sided cilia, pulsating structures that mimic 
the hairs that line the human windpipe, are arranged 
in rows along the underside of the robot. (Credit: John 
Suh, Stanford University)

The past few years have given rise to a growing number of microrobots, miniaturized mobile machines designed to perform specific tasks. And though spectators might need magnifying glasses to see the action, some think the time has come for a microrobotics challenge.

"I'd like to see a similar competition at the small scale, where we dump these microrobots from a plane and have them go off and run for days and just do what they've been told," said Karl Böhringer, a University of Washington professor of electrical engineering. "That would require quite an effort at this point, but I think it would be a great thing."

Researchers at the UW and Stanford University have developed what might one day be a pint-sized contender. Böhringer is lead author of a paper in the June issue of the Journal of Microelectromechanical Systems introducing an insectlike robot with hundreds of tiny legs.

Compared to other such robots, the UW model excels in its ability to carry heavy loads -- more than seven times its own weight -- and move in any direction.

Someday, tiny mobile devices could crawl through cracks to explore collapsed structures, collect environmental samples or do other tasks where small size is a benefit. The UW's robot weighs half a gram (roughly one-hundredth of an ounce), measures about 1 inch long by a third of an inch wide, and is about the thickness of a fingernail.

Technically it is a centipede, with 512 feet arranged in 128 sets of four. Each foot consists of an electrical wire sandwiched between two different materials, one of which expands under heat more than the other. A current traveling through the wire heats the two materials and one side expands, making the foot curl. Rows of feet shuffle along in this way at 20 to 30 times each second.

"The response time is an interesting point about these tiny devices," Böhringer said. "On your stove, it might take minutes or even tens of minutes to heat something up. But on the small scale it happens much, much faster."

The legs' surface area is so large compared to their volume that they can heat up or cool down in just 20 milliseconds.

"It's one of the strongest actuators that you can get at the small scale, and it has one of the largest ranges of motion," Böhringer said. "That's difficult to achieve at the small scale."

The microchip, the robot's body and feet, was first built in the mid 1990s at Stanford University as a prototype part for a paper-thin scanner or printer. A few years later the researchers modified it as a docking system for space satellites. Now they have flipped it over so the structures that acted like moving cilia are on the bottom, turning the chip into an insectlike robot.

"There were questions about the strength of the actuators. Will they be able to support the weight of the device?" Böhringer said. "We were surprised how strong they were. For these things that look fragile, it's quite amazing."

The tiny legs can move more than just the device. Researchers were able to pile paper clips onto the robot's back until it was carrying more than seven times its own weight. This means that the robot could carry a battery and a circuit board, which would make it fully independent. (It now attaches to nine threadlike wires that transmit power and instructions.)

Limbs pointing in four directions allow the robot flexibility of movement.

"If you drive a car and you want to be able to park it in a tight spot, you think, 'Wouldn't it be nice if I could drive in sideways,'" Böhringer said. "Our robot can do that -- there's no preferred direction."

Maneuverability is important for a robot intended to go into tight spaces.

The chip was not designed to be a microrobot, so little effort was made to minimize its weight or energy consumption. Modifications could probably take off 90 percent of the robot's weight, Böhringer said, and eliminate a significant fraction of its power needs.

As with other devices of this type, he added, a major challenge is the power supply. A battery would only let the robot run for 10 minutes, while researchers would like it to go for days.

Another is speed. Right now the UW robot moves at about 3 feet per hour -- and it's far from the slowest in the microrobot pack.

Co-authors are former UW graduate students Yegan Erdem, Yu-Ming Chen and Matthew Mohebbi; UW electrical engineering professor Robert Darling; John Suh at General Motors; and Gregory Kovacs at Stanford.

Research funding was provided by the U.S. Defense Advanced Research Projects Agency, the National Science Foundation and General Motors Co.

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How We Know A Dog Is A Dog: Concept Acquisition In The Human Brain

How We Know A Dog Is A Dog: Concept Acquisition In The Human Brain

  10:35:00 AM    Science Lover

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A new study explores how our brains synthesize concepts that allow us to organize and comprehend the world. The research, published by Cell Press in the September 24th issue of the journal Neuron, uses behavioral and neuroimaging techniques to track how conceptual knowledge emerges in the human brain and guides decision making.

Although two dogs can look very different, the human brain recognizes them as particular instances of the concept of a dog. (Credit: iStockphoto/Annette Wiechmann)







The ability to use prior knowledge when dealing with new situations is a defining characteristic of human intelligence. This is made possible through the use of concepts, which are formed by abstracting away the common essence from multiple distinct but related entities. "Although a Poodle and a Golden Retriever look very different from each other, we can easily appreciate their similar attributes because they can be recognized as instances of a particular concept, in this case a dog," explains lead study author, Dr. Dharshan Kumaran from the Wellcome Trust Centre for Neuroimaging at University College London.

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Soon, a portable unit of surgical robots to replace army medics on battlefields

Soon, a portable unit of surgical robots to replace army medics on battlefields

  8:20:00 PM    Science Lover

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The Trauma Pod unit in action

Researchers in the US are working on a project that could replace army medics on a battlefield with robotic surgeons and nurses in the next 10 years.

The ‘Trauma Pod’ – being developed by US’ Defence Advanced Research Projects Agency (DARPA) - is currently undergoing trials.

Brendan Visser, a surgeon at Stanford University in California who helped develop the Trauma Pod, described it as: “Three separate robots dance over the top of the patient with their powerful arms moving very quickly, yet they don’t crash and they’re able to deliver very small items from one arm to another.”

The purpose of the Trauma Pod is to provide a quick “temporary fix” to wounded soldiers before being taken to the hospital.

“The system will focus on damage control surgery, which is the minimum necessary to stabilise someone. It could provide airway control, relieve life-threatening injuries such as a collapsed lung, or stop bleeding temporarily,” Pablo Garcia – of non-profit lab SRI International, which leads the project – told New Scientist magazine.

HOW IT WORKS

The Trauma Pod unit comprises one three-armed surgeon robot, assisted by 12 other robotic systems.

Remotely controlled by a human, the surgeon bot communicates with and instructs the other robots. One of its three arms holds an endoscope to allow the human controller to see inside the patient, while the other two grip surgical tools.

Garcia added that the robot could be allowed to carry out some simple tasks without human help, such as placing stitches or tying knots.

The bed itself monitors vital signs, administers fluids and oxygen, and may eventually administer anaesthesia.

A voice-activated robotic arm “Hot Lips” - derived from the nickname of a nurse in the TV series M*A*S*H - passes fresh tools and supplies to the surgeon bot. A third “circulating nurse” robot gives out the right tools.

The Trauma Pod unit recently passed the first phase of a feasibility trial, where robots treated a mannequin with bullet injuries by inserting a plastic tube into a damaged blood vessel and operating to close a perforated bowel.

The team hopes to eventually shrink the Trauma Pod to a collapsible unit encased in a portable shell that can be carried on the back of a vehicle.

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