Giant Nasa Rover Launches to Mars
|2:33:17 PM, Saturday, November 26, 2011|
"Nasa has launched the most capable machine ever built to land on Mars.
The near one-tonne rover, tucked inside a capsule, left Florida on an Atlas 5 rocket at 10:02 local time (15:02 GMT).
Nicknamed Curiosity, the rover will take eight and a half months to cross the vast distance to its destination.
If it can land safely next August, the robot will then scour Martian soils and rocks for any signs that current or past environments on the planet could have supported microbial life.
The Atlas flight lasted almost three-quarters of an hour.
By the time the encapsulated rover was ejected on a path to the Red Planet, it was moving at 10km/s (6 miles per second).
Spectacular video taken from the upper-stage of the rocket showed it drifting off into the distance.
"Our spacecraft is in excellent health and it's on its way to Mars," said Curiosity project manager Peter Theisinger.
Nasa received a first communication from the cruising spacecraft about 50 minutes after lift-off through a tracking station in Canberra, Australia.
Controllers will command a course correction manoeuvre in two weeks to refine the trajectory to the Red Planet.
The rover - also known as the Mars Science laboratory (MSL) - is due to arrive at the Red Planet in early August 2012. Then, the hard part begins - landing safely.
One senior space agency official this week called Mars the "Death Planet" because so many missions have failed to get down in one piece.
The Americans, though, have a good recent record and they believe a new rocket-powered descent system will be able to place the rover very precisely in one of the most exciting locations on the planet.
It is being aimed at a deep equatorial depression called Gale Crater, which contains a central mountain that rises some 5km (3 miles) above the plain below.
The crater was chosen as the landing site because satellite imagery has suggested that surface conditions at some point in time may have been benign enough to sustain micro-organisms.
This included pictures of sediments at the base of the peak that were clearly laid down in the presence of abundant water.
MSL is equipped with 10 sophisticated instruments to study the rocks, soils and atmosphere in Gale Crater.
The $2.5bn (Ł1.6bn) mission is funded for an initial two Earth years of operations, but MSL-Curiosity has a plutonium battery and so should have ample power to keep rolling for more than a decade.
It is likely the mechanisms on the rover will wear out long before its energy supply.
"The agency is ecstatic," observed Doug McCuistion, Nasa's Mars exploration programme director.
"We have started a new era of exploration, not just technologically but scientifically as well.
"I hope we have more work than the scientists can handle. When we get to the surface, I expect them all to be overrun with data they've never seen before. I expect the public to have images, vistas that we've never seen before.
"Down in the bottom of Gale Crater, those images are going to be just stunning I believe. It will be like sitting at the bottom of the Grand Canyon, I think.""
'US Should Freeze Deployment of Anti-Missile Systems in European Countries'
|3:12:42 AM, Friday, November 25, 2011|
"Russia is pushing hard for a joint European missile defense system with NATO, a system which is spearheaded by the US. But as of late, Moscow has been complaining about lukewarm co-operation from its Western partners.
The US should freeze the current deployment of US anti-missile systems in certain European countries, Konstantin Kosachev, the head of the State Duma Foreign Affairs Committee told RT.
At the G8 summit in France last week, Russia’s president Dmitry Medvedev said the US could spark a new arms race if it keeps building its missile defense system in Europe. According to Kosachev, there are some ways to avoid this, though “nobody believes we will ever have a joint button to be pushed simultaneously by the two participants.”
“Number one is not to take any practical steps immediately to create a future global anti-missile system. Number two is to make a legally-binding agreement on the purposes of the future system and to ensure the US or NATO system will not be aimed at Russia. And number three is to start practical co-operation on exchange of information on missile launches and to introduce certain elements of joint commander on the future integrated anti-missile system,” said Kosachev.
Whether or not the US decides to keep building up its missile defense system and military potential in Europe, and Russia’s response to that is a matter for the future negotiations, said Kosachev.
“As for tactical nuclear weapons, Russia now does not have any tactical nuclear weapons outside its borders, while the US have deployed certain amounts of these armaments in five or six European countries, so the first step to be taken here is to get tactical nuclear weapons inside national borders of each country that possesses these types of weapons and, later on, start further negotiations. When that happens, Russia will be ready to enter the process,” Kosachev said.
Missile defense, along with its global implications, is to become one of the main issues at the meeting between Russian and the NATO defense ministers in Berlin on June 9, and also of the next summit of Russia and the European Union in Nizhny Novgorod on June 9 and 10.
Russia warned it would consider withdrawing from the latest Russian-American Strategic Arms Reduction Treaty, New START, if there was no progress.
“There was no sufficient progress in any of the cases because NATO countries in Europe are not ready to take on the expenditures for the expensive system. They want the US to spend their money on European security. And in the dialogue between NATO and Russia, we discuss all possible options. But as nobody knows how NATO will behave, we are not making any progress here either,” Kosachev believes."
Mystery of Dead Sea Scroll Authors Possibly Solved
|2:57:26 AM, Friday, November 25, 2011|
"The Dead Sea Scrolls may have been written, at least in part, by a sectarian group called the Essenes, according to nearly 200 textiles discovered in caves at Qumran, in the West Bank, where the religious texts had been stored.
Scholars are divided about who authored the Dead Sea Scrolls and how the texts got to Qumran, and so the new finding could help clear up this long-standing mystery.
The research reveals that all the textiles were made of linen, rather than wool, which was the preferred textile used in ancient Israel. Also they lack decoration, some actually being bleached white, even though fabrics from the period often have vivid colours. Altogether, researchers say these finds suggest that the Essenes, an ancient Jewish sect, "penned" some of the scrolls.
Not everyone agrees with this interpretation. An archaeologist who has excavated at Qumran told LiveScience that the linen could have come from people fleeing the Roman army after the fall of Jerusalem in A.D. 70, and that they are in fact responsible for putting the scrolls into caves.
The Dead Sea Scrolls consist of nearly 900 texts, the first batch of which were discovered by a Bedouin shepherd in 1947. They date from before A.D. 70, and some may go back to as early as the third century B.C. The scrolls contain a wide variety of writings including early copies of the Hebrew Bible, along with hymns, calendars and psalms, among other works.
Nearly 200 textiles were found in the same caves, along with a few examples from Qumran, the archaeological site close to the caves where the scrolls were hidden.
Orit Shamir, curator of organic materials at the Israel Antiquities Authority, and Naama Sukenik, a graduate student at Bar-Ilan University, compared the white-linen textiles found in the11 caves to examples found elsewhere in ancient Israel, publishing their results in the most recent issue of the journal Dead Sea Discoveries.
A breakthrough in studying these remains was made in 2007 when a team of archaeologists was able to ascertain that colorful wool textiles found at a site to the south of Qumran, known as the Christmas Cave, were not related to the inhabitants of the site. This meant that Shamir and Sukenik were able to focus on the 200 textiles found in the Dead Sea Scroll caves and at Qumran itself, knowing that these are the only surviving textiles related to the scrolls.
They discovered that every single one of these textiles was made of linen, even though wool was the most popular fabric at the time in Israel. They also found that most of the textiles would have originally been used as clothing, later being cut apart and re-used for other purposes such as bandages and for packing the scrolls into jars.
Some of the textiles were bleached white and most of them lacked decoration, even though decoration is commonly seen in textiles from other sites in ancient Israel.
According to the researchers the finds suggest that the residents of Qumran dressed simply.
"They wanted to be different than the Roman world," Shamir told LiveScience in a telephone interview. "They were very humble, they didn't want to wear colorful textiles, they wanted to use very simple textiles."
The owners of the clothing likely were not poor, as only one of the textiles had a patch on it."This is very, very, important," Shamir said. "Patching is connected with [the] economic situation of the site."
Shamir pointed out that textiles found at sites where people were under stress, such as at the Cave of Letters, which was used in a revolt against the Romans, were often patched. On the other hand "if the site is in a very good economic situation, if it is a very rich site, the textiles will not be patched," she said. With Qumran, "I think [economically] they were in the middle, but I'm sure they were not poor."
Robert Cargill, a professor at the University of Iowa, has written extensively about Qumran and has developed a virtual model of it. He said that archaeological evidence from the site, including coins and glassware, also suggests the inhabitants were not poor..."
New Find Sheds Light on Ancient Site in Jerusalem
|2:41:56 PM, Wednesday, November 23, 2011|
"JERUSALEM (AP) — Newly found coins underneath Jerusalem's Western Wall could change the accepted belief about the construction of one of the world's most sacred sites two millennia ago, Israeli archaeologists said Wednesday.
The man usually credited with building the compound known to Jews as the Temple Mount and to Muslims as the Noble Sanctuary is Herod, a Jewish ruler who died in 4 B.C. Herod's monumental compound replaced and expanded a much older Jewish temple complex on the same site.
But archaeologists with the Israel Antiquities Authority now say diggers have found coins underneath the massive foundation stones of the compound's Western Wall that were stamped by a Roman proconsul 20 years after Herod's death. That indicates that Herod did not build the wall — part of which is venerated as Judaism's holiest prayer site — and that construction was not close to being complete when he died.
"The find changes the way we see the construction, and shows it lasted for longer than we originally thought," said the dig's co-director, Eli Shukron.
The four bronze coins were stamped around 17 A.D. by the Roman official Valerius Gratus. He preceded Pontius Pilate of the New Testament story as Rome's representative in Jerusalem, according to Ronny Reich of Haifa University, one of the two archaeologists in charge of the dig.
The coins were found inside a ritual bath that predated construction of the renovated Temple Mount complex and which was filled in to support the new walls, Reich said.
They show that construction of the Western Wall had not even begun at the time of Herod's death. Instead, it was likely completed only generations later by one of his descendants.
The coins confirm a contemporary account by Josephus Flavius, a Jewish general who became a Roman historian. Writing after a Jewish revolt against Rome and the destruction of the Temple by legionnaires in 70 A.D., he recounted that work on the Temple Mount had been completed only by King Agrippa II, Herod's great-grandson, two decades before the entire compound was destroyed.
Scholars have long been familiar with Josephus' account, but the find is nonetheless important because it offers the "first clear-cut archaeological evidence that part of the enclosure wall was not built by Herod," said archaeologist Aren Maeir of Bar-Ilan University, who was not involved in the dig.
Josephus also wrote that the end of construction left 18,000 workmen unemployed in Jerusalem. Some historians have linked this to discontent that eventually erupted in the Jewish revolt.
The compound, controlled since 1967 by Israel, now houses the Al-Aqsa Mosque and the golden-capped Muslim shrine known as the Dome of the Rock. The fact that the compound is holy both to Jews and Muslims makes it one of the world's most sensitive religious sites.
The dig in which the coins were discovered cleared a Roman-era drainage tunnel that begins at the biblical Pool of Siloam, one of the city's original water sources, and terminates with a climb up a ladder out onto a 2,000-year-old street inside Jerusalem's Old City. The tunnel runs by the foundation stones of the compound's western wall, where the coins were found.
The drainage tunnel was excavated as part of the dig at the City of David, which is perhaps Israel's richest archaeological excavation and its most contentious.
The dig is being carried out inside the Palestinian neighborhood of Silwan, and is funded by a group associated with the Israeli settlement movement that opposes any division of the city as part of a future peace deal.
The excavation of the tunnel has also yielded a Roman sword, oil lamps, pots and coins that scholars believe are likely debris from an attempt by Jewish rebels to hide in the underground passage as they fled from the Roman soldiers."
Russia's Stranded Mars Probe Sends Signal to Earth
|2:37:07 PM, Wednesday, November 23, 2011|
"Engineers fought desperately on Wednesday to save Russia's Phobos-Grunt spacecraft after the Martian probe sent "a first sign of life" more than two weeks after being stranded in orbit.
After days of frustrating silence, contact with the probe was made on Tuesday at 2025 GMT at a European Space Agency ground station in Perth, Western Australia, the Paris-based ESA said.
"ESA teams are working closely with engineers in Russia to determine how best to maintain communication with the spacecraft," it said.
A spokesman at European Space Operations Centre (ESOC) in Darmstadt, Germany, told AFP: "We sent an instruction to (the probe) to switch on its transmitter and the probe sent us telemetric data.
"However, we do not have all the details and we are not very sure of what we received. It's a first sign of life," he said.
The probe is in a "very low, very unfavourable orbit (that) is difficult to identify accurately," the spokesman added.
The task is being complicated by very narrow windows for communication "of between five and 10 minutes," he explained.
The five-billion-ruble ($165-million) mission is one of the most ambitious in the history of Martian exploration.
It is designed to travel to the moon of Phobos, scoop up soil and return the sample to Earth by 2014.
But mission control lost radio contact with the craft hours after launch on November 8, leaving engineers bewildered as to where it was. On Tuesday, Russia's space agency had said it saw "little chance" of saving the 13.5-tonne vessel.
In Moscow, the Russian space agency Roskosmos confirmed the ESA report.
It said the Perth station had received a radio signal from Phobos-Grunt during a scheduled monitoring period and European and Russian were "appraising the situation."
The probe blasted off successfully from the Baikonur cosmodrome but did not manage to leave its Earth orbit as planned.
Motors failed to fire twice to steer it on a course for Mars, and it is still carrying the fuel that would have been used in this manoeuvre.
But before losing control of the probe, the Russians sent out instructions for it to deploy its solar panels, an ESA official said.
"Initially, it was thought that the spacecraft would die after three days when its battery ran out.
"But the solar panels played a crucial role yesterday, enabling the ground station in Perth to make contact," the source said.
Perth is the sole means of communicating with Phobos-Grunt as it is the only listening post in a part of the Earth that is in daylight when the probe passes overhead, the official explained.
Exposure to the sunlight provides electricity to the spacecraft, enabling to briefly talk to the ground. But it loses power when it moves over ground stations in parts of the globe that are in night.
Phobos-Grunt is also carrying a Chinese satellite, Yinghuo-1, which was to go into orbit around Mars in a landmark space cooperation between Moscow and Beijing.
Orbiting Mars at just under 10,000 kilometres (6,000 miles) distance, Phobos is believed to be the closest moon to any planet in the Solar System. It has long intrigued scientists, who believe it holds secrets about the origins of the planets."
Olympus BioScapes Competition 2011 Winners: Incredible Microscopic Images Of The Natural World
|6:38:39 PM, Sunday, November 20, 2011|
"The Olympus BioScapes competition has produced some of the world's most stunning microscopic digital images and videos of life science.
Now in its eighth year running, the winning entry is a photograph by Charles Krebs of Issaquah, Washington showing an underwater Rotifer Floscularia that relies on rapidly beating cilia to bring food-laden water in so it can feed.
From live green brain coral captured underwater to stink bug eggs snapped in Greece, you'll see some breathtaking photos of nature at its most beautiful.
Other images not to be missed include the reproductive system of a fruit fly and the golden chloroplasts in a living diatom..."
Scientists Create Light from Vacuum
|5:38:31 PM, Sunday, November 20, 2011|
"Scientists at Chalmers University of Technology have succeeded in creating light from vacuum - observing an effect first predicted over 40 years ago. The results will be published tomorrow (Wednesday) in the journal Nature. In an innovative experiment, the scientists have managed to capture some of the photons that are constantly appearing and disappearing in the vacuum.
The experiment is based on one of the most counterintuitive, yet, one of the most important principles in quantum mechanics: that vacuum is by no means empty nothingness. In fact, the vacuum is full of various particles that are continuously fluctuating in and out of existence. They appear, exist for a brief moment and then disappear again. Since their existence is so fleeting, they are usually referred to as virtual particles.
Chalmers scientist, Christopher Wilson and his co-workers have succeeded in getting photons to leave their virtual state and become real photons, i.e. measurable light. The physicist Moore predicted way back in 1970 that this should happen if the virtual photons are allowed to bounce off a mirror that is moving at a speed that is almost as high as the speed of light. The phenomenon, known as the dynamical Casimir effect, has now been observed for the first time in a brilliant experiment conducted by the Chalmers scientists.
"Since it's not possible to get a mirror to move fast enough, we've developed another method for achieving the same effect," explains Per Delsing, Professor of Experimental Physics at Chalmers. "Instead of varying the physical distance to a mirror, we've varied the electrical distance to an electrical short circuit that acts as a mirror for microwaves.
The "mirror" consists of a quantum electronic component referred to as a SQUID (Superconducting quantum interference device), which is extremely sensitive to magnetic fields. By changing the direction of the magnetic field several billions of times a second the scientists were able to make the "mirror" vibrate at a speed of up to 25 percent of the speed of light.
"The result was that photons appeared in pairs from the vacuum, which we were able to measure in the form of microwave radiation," says Per Delsing. "We were also able to establish that the radiation had precisely the same properties that quantum theory says it should have when photons appear in pairs in this way."
What happens during the experiment is that the "mirror" transfers some of its kinetic energy to virtual photons, which helps them to materialise. According to quantum mechanics, there are many different types of virtual particles in vacuum, as mentioned earlier. Goran Johansson, Associate Professor of Theoretical Physics, explains that the reason why photons appear in the experiment is that they lack mass.
"Relatively little energy is therefore required in order to excite them out of their virtual state. In principle, one could also create other particles from vacuum, such as electrons or protons, but that would require a lot more energy."
The scientists find the photons that appear in pairs in the experiment interesting to study in closer detail. They can perhaps be of use in the research field of quantum information, which includes the development of quantum computers.
However, the main value of the experiment is that it increases our understanding of basic physical concepts, such as vacuum fluctuations - the constant appearance and disappearance of virtual particles in vacuum. It is believed that vacuum fluctuations may have a connection with "dark energy" which drives the accelerated expansion of the universe. The discovery of this acceleration was recognized this year with the awarding of the Nobel Prize in Physics."
NASA Probe Data Show Evidence of Liquid Water on Icy Europa
|5:32:59 PM, Wednesday, November 16, 2011|
â€śData from a NASA planetary mission have provided scientists evidence of what appears to be a body of liquid water, equal in volume to the North American Great Lakes, beneath the icy surface of Jupiter's moon, Europa. The data suggest there is significant exchange between Europa's icy shell and the ocean beneath. This information could bolster arguments that Europa's global subsurface ocean represents a potential habitat for life elsewhere in our solar system. The findings are published in the scientific journal Nature. "The data opens up some compelling possibilities," said Mary Voytek, director of NASA's Astrobiology Program at agency headquarters in Washington. "However, scientists worldwide will want to take a close look at this analysis and review the data before we can fully appreciate the implication of these results." NASA's Galileo spacecraft, launched by the space shuttle Atlantis in 1989 to Jupiter, produced numerous discoveries and provided scientists decades of data to analyze. Galileo studied Jupiter, which is the most massive planet in the solar system, and some of its many moons. One of the most significant discoveries was the inference of a global salt water ocean below the surface of Europa. This ocean is deep enough to cover the whole surface of Europa and contains more liquid water than all of Earth's oceans combined. However, being far from the sun, the ocean surface is completely frozen. Most scientists think this ice crust is tens of miles thick. "One opinion in the scientific community has been if the ice shell is thick, that's bad for biology. That might mean the surface isn't communicating with the underlying ocean," said Britney Schmidt, lead author of the paper and postdoctoral fellow at the Institute for Geophysics, University of Texas at Austin. "Now, we see evidence that it's a thick ice shell that can mix vigorously and new evidence for giant shallow lakes. That could make Europa and its ocean more habitable." Schmidt and her team focused on Galileo images of two roughly circular, bumpy features on Europa's surface called chaos terrains. Based on similar processes seen on Earth -- on ice shelves and under glaciers overlaying volcanoes -- they developed a four-step model to explain how the features form. The model resolves several conflicting observations. Some seemed to suggest the ice shell is thick. Others suggest it is thin. This recent analysis shows the chaos features on Europa's surface may be formed by mechanisms that involve significant exchange between the icy shell and the underlying lake. This provides a mechanism or model for transferring nutrients and energy between the surface and the vast global ocean already inferred to exist below the thick ice shell. This is thought to increase the potential for life there. The study authors have good reason to believe their model is correct, based on observations of Europa from Galileo and of Earth. Still, because the inferred lakes are several miles below the surface, the only true confirmation of their presence would come from a future spacecraft mission designed to probe the ice shell. Such a mission was rated as the second highest priority flagship mission by the National Research Council's recent Planetary Science Decadal Survey and is being studied by NASA. "This new understanding of processes on Europa would not have been possible without the foundation of the last 20 years of observations over Earth's ice sheets and floating ice shelves," said Don Blankenship, a co-author and senior research scientist at the Institute for Geophysics, where he leads airborne radar studies of the planet's ice sheets. Galileo was the first spacecraft to directly measure Jupiter's atmosphere with a probe and conduct long-term observations of the Jovian system. The probe was the first to fly by an asteroid and discover the moon of an asteroid. NASA extended the mission three times to take advantage of Galileo's unique science capabilities, and it was put on a collision course into Jupiter's atmosphere in September 2003 to eliminate any chance of impacting Europa. The Galileo mission was managed by NASA's Jet Propulsion Laboratory in Pasadena, Calif., for the agency's Science Mission Directorate.â€ť
Transporter 5: Solving an Ancient Mystery of the Cell
|9:04:27 PM, Tuesday, November 15, 2011|
â€śThe discovery by scientists in Cambridge and Alberta of a fifth adaptor protein â€“ a tiny and vital component of many cells â€“will lay the foundations for a greater understanding of genetic disorders.
The people who work there call it the Titanic. The Cambridge Institute for Medical Research, a shiny building with funnel-like air vents on the Addenbrookeâ€™s complex, is the workplace of around 250 scientists, many of them internationally acclaimed in their fields. Its 40 research groups are dedicated to advancing the basic and clinical science that is needed to understand the molecular mechanisms of disease. It is in these laboratories that some of the foundational research takes place that will pave the way for the development of drugs and therapies that will save lives in the future.
Earlier this year one of these groups â€“ a team of seven scientists led by eminent cell biologist Professor Margaret Robinson â€“ made a discovery that will lead to some of the key information contained in cell biology textbooks being revised. Working with colleagues at the University of Alberta in Canada, the team showed that the cells of all eukaryotes (a term used to describe the cell structure of animals, plants and fungi) contain five adaptor protein complexes (APs). This finding confounds existing assumptions that only four APs are present in cells â€“ and will help scientists learn more about, and ultimately treat, certain genetic disorders.
Scientists have known about the existence of APs â€“ which are vital to the functions of cells â€“ ever since the late 1970s. Four APs were identified by researchers in the space of some 20 years. â€śAs recently as 2004 I was quoted in the scientific literature stating categorically that there were no more than four APs,â€ť says Professor Robinson. â€śIt just goes to show that you canâ€™t be too certain that youâ€™ve found everything there is to find. And even more importantly it illustrates just how vital it is to carry out fundamental research, to provide the knowledge needed to feed into the translational research that could ultimately lead to cures for diseases.â€ť
Cells are often described as the building blocks of life. As every school child is taught, cells have a nucleus, a surrounding membrane and cytoplasm. The intricate workings of the cell, however, are much more complex and represent a fascinating puzzle for biologists. Cells are full of compartments, visible only through the most powerful microscopes. These compartments do not exist in isolation but communicate with each other â€“ for example, to send newly-made molecules from the place where they are manufactured to the place where they need to be in order to function.
Tiny spherical vesicles transport proteins and other molecules around the cell in a process that scientists call trafficking. But in order for the different compartments not to get mixed up, the cell needs to put some molecules into vesicles as cargo to be delivered to a new compartment, while leaving others behind. The machinery that selects which molecules will go into the vesicles includes the adaptor proteins. The word adaptor is used to describe their ability to connect two different types of molecules together: the cargo and the structural proteins that physically form the vesicle.
The way in which adaptor proteins pick up molecules from compartments can be likened to diners in a sushi bar, picking up dishes of food from a passing conveyor belt avoiding items they dislike and opting for those they desire. â€śAPs have different ways of recognising molecules. Itâ€™s a process that we are only just beginning to understand, but this fundamental research could impact on the study of diseases where certain molecules fail to get trafficked correctly,â€ť says Dr. Jennifer Hirst, who is a senior researcher in the Robinson lab and has discovered and characterised a number of new adaptorsâ€¦â€ť
Mimicking the Brain -- In Silicon: New Computer Chip Models How Neurons Communicate With Each Other at Synapses
|8:58:20 PM, Tuesday, November 15, 2011|
â€śFor decades, scientists have dreamed of building computer systems that could replicate the human brain's talent for learning new tasks.
MIT researchers have now taken a major step toward that goal by designing a computer chip that mimics how the brain's neurons adapt in response to new information. This phenomenon, known as plasticity, is believed to underlie many brain functions, including learning and memory.
With about 400 transistors, the silicon chip can simulate the activity of a single brain synapse -- a connection between two neurons that allows information to flow from one to the other. The researchers anticipate this chip will help neuroscientists learn much more about how the brain works, and could also be used in neural prosthetic devices such as artificial retinas, says Chi-Sang Poon, a principal research scientist in the Harvard-MIT Division of Health Sciences and Technology.
Poon is the senior author of a paper describing the chip in the Proceedings of the National Academy of Sciences the week of Nov. 14. Guy Rachmuth, a former postdoc in Poon's lab, is lead author of the paper. Other authors are Mark Bear, the Picower Professor of Neuroscience at MIT, and Harel Shouval of the University of Texas Medical School.
There are about 100 billion neurons in the brain, each of which forms synapses with many other neurons. A synapse is the gap between two neurons (known as the presynaptic and postsynaptic neurons). The presynaptic neuron releases neurotransmitters, such as glutamate and GABA, which bind to receptors on the postsynaptic cell membrane, activating ion channels. Opening and closing those channels changes the cell's electrical potential. If the potential changes dramatically enough, the cell fires an electrical impulse called an action potential.
All of this synaptic activity depends on the ion channels, which control the flow of charged atoms such as sodium, potassium and calcium. Those channels are also key to two processes known as long-term potentiation (LTP) and long-term depression (LTD), which strengthen and weaken synapses, respectively.
The MIT researchers designed their computer chip so that the transistors could mimic the activity of different ion channels. While most chips operate in a binary, on/off mode, current flows through the transistors on the new brain chip in analog, not digital, fashion. A gradient of electrical potential drives current to flow through the transistors just as ions flow through ion channels in a cell.
"We can tweak the parameters of the circuit to match specific ion channels," Poon says. "We now have a way to capture each and every ionic process that's going on in a neuron."
Previously, researchers had built circuits that could simulate the firing of an action potential, but not all of the circumstances that produce the potentials. "If you really want to mimic brain function realistically, you have to do more than just spiking. You have to capture the intracellular processes that are ion channel-based," Poon says.
The new chip represents a "significant advance in the efforts to incorporate what we know about the biology of neurons and synaptic plasticity onto CMOS [complementary metal-oxide-semiconductor] chips," says Dean Buonomano, a professor of neurobiology at the University of California at Los Angeles, adding that "the level of biological realism is impressive.
The MIT researchers plan to use their chip to build systems to model specific neural functions, such as the visual processing system. Such systems could be much faster than digital computers. Even on high-capacity computer systems, it takes hours or days to simulate a simple brain circuit. With the analog chip system, the simulation is even faster than the biological system itself.
Another potential application is building chips that can interface with biological systems. This could be useful in enabling communication between neural prosthetic devices such as artificial retinas and the brain. Further down the road, these chips could also become building blocks for artificial intelligence devices, Poon saysâ€¦.â€ť
Dewayne Dedmon's Leap Of Faith: Discouraged for Religious Reasons from Playing Basketball
|1:59:36 AM, Friday, November 11, 2011|
"Thou wilt show me the path of life.
Dieter Horton first caught sight of the skinny kid with the long arms one afternoon in April 2008. The boy was sitting in the first row of the bleachers in the small gym at Antelope Valley College, waiting silently, his knees together. Only when he stood up, 30 minutes later, did Horton realize just how tall he was. At least 6'8", Horton thought. Then he looked closer: Who the hell is this kid?
After all, AVC is located in Lancaster, Calif., in the heart of the Antelope Valley, only an hour's drive north of Los Angeles over the San Gabriel Mountains but in a world of its own. If there was a teenager within a nose of 6'6" in the valley, Horton could tell you his home address, his girlfriend's name and what he liked on his pizza. In 11 years as a junior college basketball coach in California, Horton had won a state title, sent nearly 20 kids to Division I schools and set a state juco record by finishing 37--0 at Fullerton College in 2005--06. Young, ambitious and handsome in a clean-cut way, Horton scouted so relentlessly that his phys-ed students had grown accustomed to his teaching with a cellphone pressed to his ear. Yet here was a towering kid unfamiliar to the coach from local high schools or the AAU circuit or even city rec leagues.
When Horton finished talking with one of his players, the boy walked over. He wore an enormous pair of beat-up hightops, ratty shorts and a white T-shirt so large it looked like a muumuu. He hunched over, as if trying to shrink to standard proportions. "Coach," he said, "my name is Dewayne Dedmon. I want to play basketball."
Instantly Horton recognized the name. For years stories had floated around the valley about a tall kid who wasn't allowed to play basketball, but the coach had never believed them. He heard lots of stories. Most came from the kids themselves. Every year dozens of cocky teenagers approached Horton and assured him they'd score 20 a game if only he'd give them a uniform and the rock. To weed out the dreamers and boasters, he told them, "Come back next week." Only one in 10 ever did.
"O.K., Dewayne Dedmon, how about we see what you got," Horton said. "Show up next Tuesday at 3 p.m., and we'll work you out."
Dedmon nodded. "Yes, sir," he said. "I'll see you then."
Within a few days, Horton had forgotten all about him.
Gail Lewis was so proud she felt like crying. She stared at the letters on the notepaper stuck to the wall and read along. She knew the line, from Proverbs. Then she looked down at her nine-year-old son, sitting on his bed in their sparsely furnished three-bedroom apartment in Lancaster. Here he was, only halfway grown up and already disciplining himself..."
How the Potato Changed the World
|1:46:32 AM, Friday, November 11, 2011|
"When potato plants bloom, they send up five-lobed flowers that spangle fields like fat purple stars. By some accounts, Marie Antoinette liked the blossoms so much that she put them in her hair. Her husband, Louis XVI, put one in his buttonhole, inspiring a brief vogue in which the French aristocracy swanned around with potato plants on their clothes. The flowers were part of an attempt to persuade French farmers to plant and French diners to eat this strange new species.
Today the potato is the fifth most important crop worldwide, after wheat, corn, rice and sugar cane. But in the 18th century the tuber was a startling novelty, frightening to some, bewildering to othersâ€”part of a global ecological convulsion set off by Christopher Columbus.
About 250 million years ago, the world consisted of a single giant landmass now known as Pangaea. Geological forces broke Pangaea apart, creating the continents and hemispheres familiar today. Over the eons, the separate corners of the earth developed wildly different suites of plants and animals. Columbusâ€™ voyages reknit the seams of Pangaea, to borrow a phrase from Alfred W. Crosby, the historian who first described this process. In what Crosby called the Columbian Exchange, the worldâ€™s long-separate ecosystems abruptly collided and mixed in a biological bedlam that underlies much of the history we learn in school. The potato flower in Louis XVIâ€™s buttonhole, a species that had crossed the Atlantic from Peru, was both an emblem of the Columbian Exchange and one of its most important aspects.
Compared with grains, tubers are inherently more productive. If the head of a wheat or rice plant grows too big, the plant will fall over, with fatal results. Growing underground, tubers are not limited by the rest of the plant. In 2008 a Lebanese farmer dug up a potato that weighed nearly 25 pounds. It was bigger than his head.
Many researchers believe that the potatoâ€™s arrival in northern Europe spelled an end to famine there. (Corn, another American crop, played a similar but smaller role in southern Europe.) More than that, as the historian William H. McNeill has argued, the potato led to empire: â€śBy feeding rapidly growing populations, [it] permitted a handful of European nations to assert dominion over most of the world between 1750 and 1950.â€ť The potato, in other words, fueled the rise of the West.
Equally important, the European and North American adoption of the potato set the template for modern agricultureâ€”the so-called agro-industrial complex. Not only did the Columbian Exchange carry the potato across the Atlantic, it also brought the worldâ€™s first intensive fertilizer: Peruvian guano. And when potatoes fell to the attack of another import, the Colorado potato beetle, panicked farmers turned to the first artificial pesticide: a form of arsenic. Competition to produce ever-more-potent arsenic blends launched the modern pesticide industry. In the 1940s and 1950s, improved crops, high-intensity fertilizers and chemical pesticides created the Green Revolution, the explosion of agricultural productivity that transformed farms from Illinois to Indonesiaâ€”and set off a political argument about the food supply that grows more intense by the day..."
Poland's Mysterious Crooked Forest
|1:31:06 AM, Friday, November 11, 2011|
"In a tiny corner of western Poland a forest of about 400 pine trees grow with a 90 degree bend at the base of their trunks - all bent northward. Surrounded by a larger forest of straight growing pine trees this collection of curved trees, or "Crooked Forest," is a mystery.
Planted around 1930, the trees managed to grow for seven to 10 years before getting held down, in what is understood to have been human mechanical intervention. Though why exactly the original tree farmers wanted so many crooked trees is unknown."
Russia Races to Rescue Mars Probe From Earth Orbit
|1:19:59 AM, Friday, November 11, 2011|
"MOSCOW (AP) â€” A Russian spacecraft on its way to Mars with 12 tons of toxic fuel is stuck circling the wrong planet: ours. And it could come crashing back to Earth in a couple of weeks if engineers can't coax it back on track.
Space experts were hopeful Wednesday that the space probe's silent engines can be fired to send it off to Mars. If not, it will plummet to Earth. But most U.S. space debris experts think the fuel on board would explode harmlessly in the upper atmosphere and never reach the ground.
The launch mishap was the latest in a series of recent Russian failures that have raised concerns about the condition of the country's space industries.
The unmanned $170 million Phobos-Ground craft successfully got into orbit, propelled off the ground by a Zenit-2 booster rocket just after midnight Moscow time Wednesday (2016 GMT Tuesday) from the Baikonur cosmodrome in Kazakhstan. After separating from its booster, 11 minutes later, it was supposed to fire its engines twice and head to Mars.
Neither engine fired. So the spacecraft couldn't leave Earth's orbit, flying between 129 and 212 miles above Earth. And that orbit is already deteriorating, according to American satellite tracking.
The Federal Space Agency said the probe's orbit and its power sources could allow it to circle the Earth for about two weeks. That jibes with calculations made by NASA.
"From the orbits we're seeing from the U.S. Space Surveillance Network, it's going to be a couple weeks before it comes in," NASA chief debris scientist Nicholas Johnson said Wednesday afternoon. "It's not going to be that immediate."
The craft was aiming to get ground samples from Phobos, one of Mars' two moons, and return them in a daring expedition hailed by eager scientists, who said it may include bits of Mars that may have been trapped on its moon.
Federal Space Agency chief Vladimir Popovkin said the system that keeps the spacecraft pointed in the right direction may have failed. The Russian rescue effort was being hampered by a limited earth-to-space communications network. Even before the problem, flight controllers were forced to ask people in South America to scan the sky to see if the engines on the spacecraft fired.
Amateur astronomers were the first to spot the trouble when they detected the craft was stuck in an Earth orbit.
As time went on Wednesday, experts in the United States became more confident that the Russians could still get the probe going, just a day or two later than planned. There were no sightings of an explosion or partial rocket firings, which are good signs, said James Oberg, a NASA veteran who has written books on the Russian space program and who now works as a space consultant.
"I am growing more confident as we realize that the vehicle is healthy; it didn't blow up," Oberg said late Wednesday afternoon. "They have a chance of doing a Hubble repair, an Apollo 13, snatching victory out of jaws of defeat kind of thing."
The hope is that this is just a software problem that can be fixed and uploaded to the probe, said Bruce Betts, program director of the Planetary Society in the United States, a group that has a $500,000 experiment on board.
"There's a major problem, but it might be recoverable," Betts said. "The game's not over yet."
The spacecraft is 13.2 metric tons (14.6 tons). Russian data shows that most of that weight â€” about 11 metric tons (12 tons) â€” is fuel, NASA's Johnson said..."
Why Are There So Many Colors of Poisonous Frogs?
|1:04:59 AM, Friday, November 11, 2011|
"Hopping around in the Peruvian jungle, near the border with Brazil, is a menagerie of tiny poison dart frogs. Their wealth of colors and patternsâ€”some have golden heads atop white-swirled bodies, others wear full-torso tattoos of black and neon-yellow stripesâ€”act as the world's worst advertisement to predators: Don't eat me, I'm toxic. But why have so many designs evolved when a single one might do?
Evolutionary biologist Mathieu Chouteau of the University of Montreal in Canada ventured into the rainforest to find out. He was on the trail of Ranitomeya imitator, a single species of poison dart frog that comes in about 10 different patterns. That variability should be confusing for predators, he says, because the warnings are supposed to be a message to them, and it would make more sense to give them only one design to keep track of.
To figure out what was going on, Chouteau enlisted his girlfriend's help to make 3600 models of frogs, each 18 millimeters long. "It was, like, at least a month of working full-time," he says. They pressed black clay into frog-shaped molds and painted each one in one of two patterns: yellow striped or reticulated, like a giraffe, with green lines. They also made brown frogs as a nontoxic-looking control. Then Chouteau packed the frogs in his carryon baggage and flew to Peru.
The models represent the frogs that live in two different sites: one in the Amazonian lowland and one in a valley at about 500 meters above sea level. The two sites are separated by a high ridge. In one very long day at each site, Chouteau set out 900 of the frogs on leaves along narrow trails used by locals to hunt in the forest. For the next 3 days, he went back and checked them to see whether the soft clay recorded evidence of attacks by birds.
Birds mostly avoided the model that looked like the local frog, but they attacked the model that looked like the frog from the other site, Chouteau reports in the December issue of The American Naturalist. In the high valley, the land of the reticulated frogs, only 7.2% of the model frogs with the reticulated pattern were attacked, whereas 14.2% of the brown models and 26.6% of the yellow-striped models were attacked. The pattern was roughly reversed at the other site.
And that helps explain the diversity of frogs in the rainforest, Chouteau says. Different frog patterns rule at different sites, and birds keep these designs going by weeding out any frogs that deviate from the norm.
"This study shows quite nicely how, once you've got the diversity, it's stabilized," says Chris Jiggins, an evolutionary biologist at the University of Cambridge in the United Kingdom. But where the diversity comes from, he says, is "a bit of an outstanding question." It's possible that frogs with a particular pattern are somehow better suited to the environment where they live, but he thinks the differences more likely arise because of drift. Random changes in pattern get established and then keep evolving, making the frogs distinctive. "What's actually kind of surprising is the birds are really going for these frogs," he says. "You'd think, these frogs are so nasty, you wouldn't go anywhere near a poison dart frog." Maybe the rainforest is so diverse that it's always worth trying something, even something brightly colored."
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