Showing posts with label Tech-Space. Show all posts
Showing posts with label Tech-Space. Show all posts

Saturday, September 22, 2012

if you need help then this website is very useful for you

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as everyone is not perfect
somebody in different things and something people know but something other people knows better

 
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http://techn4all.com/help/


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u can join this facebook group also & write for any help i found this site & group v helpful
you can also join this facebook group also & write for any help i found this site & group v helpful
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Wednesday, April 4, 2012

New Isotope Measurement Could Alter History of Early Solar System



Scientists have calculated a new value for the half-life of samarium, an isotope used to track how our solar system came into being. Above: Superheated plasma loops following a solar flare eruption. (Credit: NASA/GSFC/SDO)
solar system might look quite different than previously thought, according to research at the U.S. Department of Energy's (DOE) Argonne National Laboratory published in Science. The study used more sensitive instruments to find a different half-life for samarium, one of the isotopes used to chart the evolution of the solar system.
"It shrinks the chronology of early events in the solar system, like the formation of planets, into a shorter time span," said Argonne physicist Michael Paul. "It also means some of the oldest rocks on Earth would have formed even earlier -- as early as 120 million years after the solar system formed, in one case of Greenland rocks."
According to current theory, everything in our solar system formed from star dust several billion years ago. Some of this dust was formed in giant supernovae explosions which supplied most of our heavy elements. One of these is the isotope samarium-146.
Samarium-146, or Sm-146, is unstable and occasionally emits a particle, which changes the atom into a different element. Using the same technique as radiocarbon dating, scientists can calculate how long it's been since the Sm-146 was created. Because Sm-146 decays extremely slowly -- on the order of millions of years -- many models use it to help determine the age of the solar system.
The number of years it takes for an isotope to decrease by half is called its half-life. Since Sm-146 emits particles so rarely, it takes a sophisticated instrument to measure this half-life.
The Argonne Tandem Linac Accelerator System, or ATLAS, is a DOE national user facility for the study of nuclear structure and astrophysics, and is just such an instrument. "It's easy for the ATLAS, used as a mass spectrometer, to pick out one Sm-146 atom in tens of billions of atoms," said physicist Richard Pardo, who manages the facility and participated in the study.
By counting Sm-146 atoms with ATLAS and tracking the particles that the sample emits, the team came up with a new calculation for its half-life: just 68 million years.
This is significantly shorter than the previously used value of 103 million years.
The new value patches some holes in current understanding, according to Paul. "The new time scale now matches up with a recent, precise dating taken from a lunar rock, and is in better agreement with dates obtained with other chronometers," Paul said.
The study was recently published in Science. Argonne scientists Catherine Deibel, Brad DiGiovine, John Greene, Dale Henderson, Cheng-Lie Jiang, Scott Marley, K. Ernst Rehm, Robert Scott, and Richard Vondrasek also participated in the study.
The work was supported by the DOE Office of Science and the Japan Society for the Promotion of Science.

Tuesday, April 3, 2012

Hubble spots first-of-its kind ‘steamy’ planet

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Our solar system comprises three types of planets, namely rocky, terrestrial worlds (Mercury, Venus, Earth, and Mars), gas giants (Jupiter and Saturn), and ice giants (Uranus and Neptune).
Planets orbiting distant stars come in an even wider variety, including lava worlds and “hot Jupiters.”
Now, observations by NASA’s Hubble Space Telescope have added a new type of planet to the mix.
By analyzing the previously discovered world GJ1214b, astronomer Zachory Berta (Harvard-Smithsonian Center for Astrophysics) and colleagues proved that it is a waterworld enshrouded by a thick, steamy atmosphere.
“GJ1214b is like no planet we know of,” said Berta.
“A huge fraction of its mass is made up of water.”
GJ1214b was discovered in 2009 by the ground-based MEarth (pronounced “mirth”) Project, which is led by CfA’s David Charbonneau.
This super-Earth is about 2.7 times Earth’s diameter and weighs almost 7 times as much. It orbits a red-dwarf star every 38 hours at a distance of 1.3 million miles, giving it an estimated temperature of 450 ° Fahrenheit.
In 2010, CfA scientist Jacob Bean and colleagues reported that they had measured the atmosphere of GJ1214b, finding it likely that the atmosphere was composed mainly of water. However, their observations could also be explained by the presence of a world-wide haze in GJ1214b’s atmosphere.
Berta and his co-authors used Hubble’s WFC3 instrument to study GJ1214b when it crossed in front of its host star. During such a transit, the star’s light is filtered through the planet’s atmosphere, giving clues to the mix of gases.
“We’re using Hubble to measure the infrared color of sunset on this world,” explained Berta.
Hazes are more transparent to infrared light than to visible light, so the Hubble observations help tell the difference between a steamy and a hazy atmosphere.
They found the spectrum of GJ1214b to be featureless over a wide range of wavelengths, or colours. The atmospheric model most consistent with the Hubble data is a dense atmosphere of water vapour.
“The Hubble measurements really tip the balance in favor of a steamy atmosphere,” said Berta.
Since the planet’s mass and size are known, astronomers can calculate the density, which works out to about 2 grams per cubic centimetre. Water has a density of 1 g/cm3, while Earth’s average density is 5.5 g/cm3. This suggests that GJ1214b has much more water than Earth, and much less rock.
As a result, the internal structure of GJ1214b would be very different than our world.
“The high temperatures and high pressures would form exotic materials like ‘hot ice’ or ‘superfluid water’ - substances that are completely alien to our everyday experience,” Berta added.
Theorists expect that GJ1214b formed farther out from its star, where water ice was plentiful, and migrated inward early in the system’s history. In the process, it would have passed through the star’s habitable zone. How long it lingered there is unknown.
GJ1214b is located in the direction of the constellation Ophiuchus, and just 40 light-years from Earth. Therefore, it’s a prime candidate for study by the next-generation James Webb Space Telescope.

Was Einstein wrong-or was cable loose?

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The world of science was upended last year when an experiment appeared to show one of iconic scientist Albert Einstein's fundamental theories was wrong - but now the lab behind it says the result could have been caused by a loose cable.
Physicists at the CERN laboratory near Geneva appeared to contradict Albert Einstein last year when they reported that sub-atomic particles called neutrinos could travel fractions of a second faster than light.
Einstein had said nothing could ever travel faster than light, and doing so would be like traveling back in time.
But James Gillies, a spokesman for CERN, said on Wednesday the lab's startling result was now in doubt.
Earlier on Wednesday, ScienceInsider, a website run by the respected American Association for the Advancement of Science, reported that the surprising result was down to a loose fibre optic cable linking a Global Positioning System satellite receiver to a computer.
Gillies confirmed that a flaw in the GPS system was now suspected as a possible cause for the surprising reading. Further testing was needed before any definite conclusions could be reached, he added.
The faster-than-light finding was recorded when 15,000 neutrino beams were pumped over three years from CERN to an underground Italian laboratory at Gran Sasso near Rome.
A possible explanation has been found. But we won't know until we have tested it out with a new beam to Gran Sasso, Gillies told Reuters in Geneva.
Physicists on the experiment, called OPERA, said when they reported it last September that they had checked and rechecked over many months anything that could have produced a misreading before announcing what they had found.
A second test whose results were announced in November appeared to provide further evidence that neutrinos were travelling faster than light. But many experts remained sceptical of a result that would have overturned one of the fundamental principles of modern physics.
Gillies said CERN would be issuing a full statement early on Thursday.

A Little Device That’s Trying to Read Your Thoughts

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Already surrounded by machines that allow him, painstakingly, to communicate, the physicist Stephen Hawking last summer donned what looked like a rakish black headband that held a feather-light device the size of a small matchbox. 
Called the iBrain, this simple-looking contraption is part of an experiment that aims to allow Dr. Hawking — long paralyzed by amyotrophic lateral sclerosis, or Lou Gehrig’s disease — to communicate by merely thinking.
The iBrain is part of a new generation of portable neural devices and algorithms intended to monitor and diagnose conditions like sleep apnea, depression and autism. Invented by a team led by Philip Low, a 32-year-old neuroscientist who is chief executive of NeuroVigil, a company based in San Diego, the iBrain is gaining attention as a possible alternative to expensive sleep labs that use rubber and plastic caps riddled with dozens of electrodes and usually require a patient to stay overnight.
“The iBrain can collect data in real time in a person’s own bed, or when they’re watching TV, or doing just about anything,” Dr. Low said.
The device uses a single channel to pick up waves of electrical brain signals, which change with different activities and thoughts, or with the pathologies that accompany brain disorders.
But the raw waves are hard to read because they must pass through the many folds of the brain and then the skull, so they are interpreted with an algorithm that Dr. Low first created for his Ph.D., earned in 2007 at the University of California, San Diego. (The original research, published in The Proceedings of the National Academy of Sciences, was done on zebra finches.)
About the Hawking experiment, he said, “The idea is to see if Stephen can use his mind to create a consistent and repeatable pattern that a computer can translate into, say, a word or letter or a command for a computer.”
The researchers traveled to Dr. Hawking’s offices in Cambridge, England, fitted him with the iBrain headband and asked him “to imagine that he was scrunching his right hand into a ball,” Dr. Low said. “Of course, he can’t actually move his hand, but the motor cortex in his brain can still issue the command and generate electrical waves in his brain.”
The algorithm, called Spears, was able to discern Dr. Hawking’s thoughts as signals, which were represented as a series of spikes on a grid.
“We wanted to see if there was any change in the signal,” Dr. Low said. “And in fact, we did see a change in the signal.” NeuroVigil plans to repeat the study in large populations of patients with A.L.S. and other neurodegenerative diseases.
These preliminary results come as Dr. Hawking’s ability to communicate diminishes as his disease progresses. The 70-year-old physicist, whose mind has produced crucial insights in theoretical physics as well as the best-seller “A Brief History of Time,” now needs several minutes to generate a simple message. He uses a pair of infrared glasses that picks up twitches in his cheek. His team in Cambridge, England, has dubbed this the “cheek switch.”
“Dr. Low and his company have done some outstanding work in this field,” Dr. Hawking said in a statement. “I am participating in this project in the hope that I can offer insights and practical advice to NeuroVigil. I wish to assist in research, encourage investment in this area, and, most importantly, to offer some future hope to people diagnosed with A.L.S. and other neurodegenerative conditions.”
The physicist has also worked with other inventors seeking to better elucidate his thoughts. Engineers at the semiconductor and computing giant Intel recently hooked up a customized computer to communicate with his cheek-reading infrared glasses, along with a voice synthesizer, a webcam for using Skype, and special monitors. Intel is developing new face-recognition software that can monitor subtle changes in expression and may help Dr. Hawking communicate more efficiently.
Scientists not connected with Dr. Low say they are encouraged by the iBrain’s potential. “Philip Low’s device is one of the best single-channel brain monitors out there,” said Ruth O’Hara, an associate professor of psychiatry and behavioral sciences at Stanford University Medical School. She plans to use the iBrain for autism studies. NeuroVigil has not said what the device will cost.
“I can’t speak to the veracity of his latest data,” which has not been published, Dr. O’Hara added, “but the preliminary data I have seen is compelling. It could be a significant contribution to the field as a window into brain architecture.”
Dr. Terry Heiman-Patterson, a neurologist and A.L.S. specialist at the Drexel University College of Medicine, said she was in discussions with NeuroVigil to use the device on A.L.S. patients, to see how they fared with it in comparison with instruments that use multiple channels and electrodes.
“Dr. Low is researching signals that look for intent, which is becoming very exciting because it looks like they may be able to do it — for Stephen Hawking and for others with A.L.S.,” Dr. Heiman-Patterson said.
“Patients want to be able to communicate beyond the yes or no with an eye blink. They want to send an e-mail, and turn off the light and, even more, to have a meaningful conversation.”
Monitors like the iBrain are also being used to assess whether experimental neurological drugs are working in clinical trials.
In 2009, NeuroVigil completed a deal with the drug giant Hoffmann-La Roche to test the iBrain. Neither company has released details of their early tests. NeuroVigil’s strategy, Dr. Low said, is to run clinical trials with Roche and other partners in industry and academia, and to seek approval from the Food and Drug Administration.
Other companies also make single-channel brain monitors, but unlike NeuroVigil they sell the devices and software directly to consumers online.
Zeo, for example, based in Massachusetts, concentrates on measuring sleep patterns through a smartphone app or a clock-radio device — available for $99 and $143, respectively. Emotiv Systems, in San Francisco, offers its Epoc headset for $299 plus a range of apps and add-ons that include neurofeedback, 3-D brain-mapping tools and games like Angry Birds, all using a combination of thoughts and facial muscle movements recorded by several electrodes that are in contact with a customer’s head.
“We have no plans to take an academic route,” said Zeo’s chief executive, Dave Dickinson, who added that his company’s customers had logged one million hours of sleep time. He would not say how many devices had been sold. Emotiv was founded in 2003 and has reportedly shipped 10,000 devices.
Dr. Low plans to team up again with Dr. Hawking this summer in Cambridge to present their initial data at a neuroscience meeting in early July. NeuroVigil will continue to work with Dr. Hawking and his team to refine their technology to decipher signals generated by Dr. Hawking’s thoughts. “At the moment I think my cheek switch is faster” than the brain-computer interface, Dr. Hawking said in an e-mail sent by an assistant, “ but should the position change I will try Philip Low’s system.”
Much work remains, however, including the integration of Dr. Hawking’s brain waves with the computers and devices that allow him to communicate.
“Wouldn’t it be wonderful,” Dr. Low said, “to have a mind like Stephen Hawking’s be able to communicate even a little bit better?”