Read more of this story at Slashdot.
Read more of this story at Slashdot.
Read more of this story at Slashdot.
Shao-Yu Chen at the Institute of Atomic and Molecular Sciences in Taiwan and associates have incorporated chlorophyll into graphene transistors to make light-activated switches, MIT Technology Review reports.
The new phototransistor design consists of two silver electrodes connected by a sheet of graphene. The graphene is then covered by a layer of chlorophyll using a method known as drop casting. .
This layer has a significant influence on the electronic characteristics of the device. When a voltage is set up between the silver electrodes, relatively little current flows. However, when the chlorophyll is zapped by light of certain frequencies, the current increases dramatically. [...]
By applying optogenetics (light stimulation) to specific neurons in the brain, researchers at INSERM (Institut national de la santé et de la recherche médicale) have re-established normal behavior in mice with pathological repetitive behavior similar to that observed in human patients suffering from obsessive-compulsive disorders.
Repetitive obsessive-compulsive disorders can become a real handicap to daily life (for example, washing hands up to 30 times a day; or checking excessively that a door is locked, etc.). Obsessive-compulsive disorders affect 2 to 3% of the population and in France, it is estimated that over one million persons are affected by this disorder.
The usual treatment for obsessive-compulsive disorders is to use pharmacological treatments (anti-depressants, neuroleptics) and/or behavioral psychotherapy. They don’t work in around one third of patients.
So it is necessary to gain better understanding of the cerebral mechanisms that cause these repetitive behavior patterns in order to provide better treatment.
Previous neuroimaging studies allowed the INSERM scientists to identify dysfunctional neuron circuits located between the front of the brain (the orbitofrontal cortex) and more deep-seated cerebral structures (ganglions at the base on the brain), in certain persons suffering from obsessive-compulsive disorders.
In this new study, Eric Burguière and his co-workers (in the laboratory of Prof. Ann Graybiel in MIT) concentrated their research on this neuron circuit to examine its function in detail and also to develop an approach to treating obsessive-compulsive disorders in a mutant mouse model.
In these mutant mice, the obsessive behavior was expressed by repeated grooming all day long, to such an extent that it caused cutaneous lesions. From a physiological point of view, these animals are failing to express a protein (caused by the absence of a gene Sapap3) that is normally present in the stratial neuron synapses, a structure that is part of the ganglions at the base of the brain and is involved in functions such as learning sequences, developing habits, or decision-making.
Initial observations of the mice allowed the researchers to show that the emergence of compulsive behavior in mutant mice was caused by a deficiency in behavioral inhibition. The mice are unable to stop the act of grooming, even when it is no longer necessary. The researchers then used recordings of the neuron activity to show that the dysfunction of communication in the brain between the neocortex and the striatum leads to hyperactivity of stratial neurons in mice.
To check this hypothesis, they used optogenetics. This method consists in modifying the previously identified neurons to make them express light-sensitive proteins known as opsins. Since these neuron cells are more sensitive to light, it becomes possible to control their activity by exciting them or inhibiting them using a simple light beam.
When the researchers used light stimulation to excite the neurons in the cortex that send messages to the striatum, the compulsive disorders of the mice were greatly attenuated.
“Our discoveries show that selective stimulation of the circuit can re-establish normal behavior in mice that originally presented pathological repetitive behavior, similar to the type of behavior observed in certain patients suffering from obsessive-compulsive disorders.” said Burguière.
Using optogenetics may allow for identifying the role played by neuron circuits in the brain that, if found to be dysfunctional, may cause pathological behavior.
“I have indeed decided to return to France as part of an Inserm team so that I can run a parallel study on the physiological and behavioral effects of deep cerebral stimulation on patients suffering from obsessive-compulsive disorders, and on mice using the optogenetics technique, in order to get a better understanding of how light stimulation works,” said Burguière.
The software, called MACH (My Automated Conversation coacH), uses a computer-generated onscreen face, along with facial, speech, and behavior analysis and synthesis software, to simulate face-to-face conversations. It then provides users with feedback on their interactions.
Social phobias affect about 15 million adults in the United States, according to the National Institute of Mental Health, and surveys show that public speaking is high on the list of such phobias. For some people, these fears of social situations can be especially acute: For example, individuals with Asperger’s syndrome often have difficulty making eye contact and reacting appropriately to social cues. But with appropriate training, such difficulties can often be overcome.
The research was led by MIT Media Lab doctoral student M. Ehsan Hoque, who says the work could be helpful to a wide range of people. “Interpersonal skills are the key to being successful at work and at home,” Hoque says. “How we appear and how we convey our feelings to others define us. But there isn’t much help out there to improve on that segment of interaction.”
Many people with social phobias, Hoque says, want “the possibility of having some kind of automated system so that they can practice social interactions in their own environment. … They desire to control the pace of the interaction, practice as many times as they wish, and own their data.”
The MACH software offers all those features, Hoque says. In fact, in randomized tests with 90 MIT juniors who volunteered for the research, the software showed its value.
First, the test subjects — all of whom were native speakers of English — were randomly divided into three groups. Each group participated in two simulated job interviews, a week apart, with MIT career counselors.
But between the two interviews, unbeknownst to the counselors, the students received help: One group watched videos of interview advice, while a second group had a practice session with the MACH simulated interviewer, but received no feedback other than a video of their own performance. Finally, a third group used MACH and then saw videos of themselves accompanied by an analysis of such measures as how much they smiled, how well they maintained eye contact, how well they modulated their voices, and how often they used filler words such as “like,” “basically” and “umm.”
Evaluations by another group of career counselors showed statistically significant improvement by members of the third group on measures including “appears excited about the job,” “overall performance,” and “would you recommend hiring this person?” In all of these categories, by comparison, there was no significant change for the other two groups.
The software behind these improvements was developed over two years as part of Hoque’s doctoral thesis work with help from his advisor, professor of media arts and sciences Rosalind Picard, as well as Matthieu Courgeon and Jean-Claude Martin from LIMSI-CNRS in France, Bilge Mutlu from the University of Wisconsin, and MIT undergraduate Sumit Gogia.
Designed to run on an ordinary laptop, the system uses the computer’s webcam to monitor a user’s facial expressions and movements, and its microphone to capture the subject’s speech. The MACH system then analyzes the user’s smiles, head gestures, speech volume and speed, and use of filler words, among other things. The automated interviewer — a life-size, three-dimensional simulated face — can smile and nod in response to the subject’s speech and motions, ask questions and give responses.
“While it may seem odd to use computers to teach us how to better talk to people, such software plays an important [role] in more comprehensive programs for teaching social skills [and] may eventually play an essential step in developing key interpersonal skills,” says Jonathan Gratch, a research associate professor of computer science and psychology at the University of Southern California who was not involved in this research. “Such programs also offer important advantages over the human role-players often used to teach such skills. They can faithfully embody a specific theory of pedagogy, and thus can be more consistent than human role-players.”
One reason the automated system’s feedback is effective, Hoque believes, is precisely because it’s not human: “It’s easier to tell the brutal truth through the [software],” he says, “because it’s objective.”
While this initial implementation was focused on helping job candidates, Hoque says training with the software could be helpful in many kinds of social interactions.
After finishing his doctorate in media arts and sciences this summer, Hoque will become an assistant professor of computer science at the University of Rochester in the fall.
Over the last two weeks I've posted the first four parts of the fantastic Standing With Stones documentary (England and Wales and Ireland), filmed over the course of a two year tour of the monuments by film-maker Michael Bott and presenter Rupert Soskin. If you're in a hurry to watch the entire thing, head to the Vimeo album that Michael Bott has put together. Otherwise, embedded in this story are the final three instalments in the series, featuring the megaliths of northern England and the Isle of Man, Scotland, and the Scottish Isles.
If you watch and enjoy the film, make sure you do the right thing by heading to the Standing With Stones website and donating a dollar or ten to the film-makers - I'm sure you'll agree its richly deserved, and we should be encouraging and helping to fund more features like this one by open-minded, independent people. They're still to recover production costs from two years of filming, so if you can spare the change do it!
Previously on TDG:
Electrodes inserted into the dragonfly’s body and brain record the electrical activity of neurons, and a custom-made chip amplifies the signals and transmits them wirelessly to a nearby computer.
The researchers came up with a clever solution to power the chip without adding so much mass that the insects couldn’t get off the ground, based on the same technology found in the RFID key card access system used in many office buildings.
There, a reader, usually a small pad next to a door, emits radio waves to create a magnetic field. When a key card gets close enough to the reader, the magnetic field induces a current that powers a chip inside the card, enabling it to transmit a code to unlock the door.
The two long antennae on the dragonfly backpack harvest radio waves and power the chip in a similar way. Eliminating the need for a battery on the backpack was the key to keeping the weight down. [...]
With a new lightweight material known as UltraRope, however, elevators should now be able to travel up to one kilometer (3,281 ft) continuously, Gizmag reports.
Using traditional steel lifting cables, they can’t go farther than 500 meters (1,640 ft) in one vertical run.
Described in research published today in the Monthly Notices of the Royal Astronomical Society, ICRAR PhD Candidate Jacinta Delhaize is studying distant galaxies to determine how much hydrogen they contain — by “stacking” their signals.
Delhaize said that one of the pieces of the puzzle is hydrogen gas and how much of it galaxies contained through the history of the Universe.
“Hydrogen is the building block of the Universe, it’s what stars form from and what keeps a galaxy ‘alive’,” said Delhaize.
“Galaxies in the past formed stars at a much faster rate than galaxies now. We think that past galaxies had more hydrogen, and that might be why their star formation rate is higher.
Delhaize and her supervisors set out to observe how much hydrogen was in far away galaxies, but the faint radio signals of this distant hydrogen gas are almost impossible to detect directly. This is where the new stacking technique comes in.
To gather enough data for her research, Delhaize detected weak signals from thousands of individual galaxies, combining them to produce a strong averaged signal that is easier to study.
The research used CSIRO’s Parkes radio telescope to survey a large section of the sky for 87 hours, collecting signals from hydrogen over an unmatched volume of space and up to two billion years back in time.
Delhaize said observing such a large volume of space meant that she could accurately calculate the average amount of hydrogen in galaxies at a certain distance from Earth, corresponding to a particular period in the Universe’s history.
This provides information that can be used in simulations of the Universe’s evolution and clues to how galaxies formed and changed over time.
Image enhancement by combining multiple images
“Usually astronomers take multiple images of the same object, then combine the images together to obtain a clearer picture (like taking a longer exposure),” Delhaize explained to KurzweilAI. “What we are doing here is combining together brief observations (like short exposures) of the hydrogen signal from many ‘different’ galaxies to get information about the average properties of the galaxies.So while we don’t know anything about any individual galaxies, we have lots of information about the average properties of a population.
“This spectral stacking has been used a few times in the past, but here we have shown that it can be used to study a very large volume of the Universe, which means you can accurately calculate the density of hydrogen out to large distances in the Universe.
“We stacked together 15,093 galaxies between 0 and 0.5 billion light years away, and 3,277 galaxies between 0.5 and 2 billion light years away. By comparing these two samples we found that there is no observable evidence for evolution in the density of hydrogen in the Universe out to this distance — that is, over the past 2 billion years, the total density of hydrogen in the Universe has not changed. Important pieces of information like this help astronomers to simulate galaxy evolution more accurately, and hence to understand the history of the Universe.”
Next-generation telescopes like the international Square Kilometre Array (SKA) and CSIRO’s Australian SKA Pathfinder (ASKAP) will be able to observe even larger volumes of the Universe with higher resolution.
“That makes them fast, accurate and perfect for studying the distant Universe. We can use the stacking technique to get every last piece of valuable information out of their observations,” said Delhaize.
Jacinta Delhaize was the 2008 Western Australian Science Student of the Year and will complete her PhD at The University of Western Australia node of ICRAR later this year. ICRAR is a joint venture between Curtin University and The University of Western Australia providing research excellence in the field of radio astronomy.