Monday, February 26, 2007

Salamander is capable of regenerating lost limbs - why not humans..

Salamander is the common name applied to approximately 500 amphibians with slender bodies, short legs, and long tails. The moist skin of the amphibians fits them to habitats either near water or under some protection on moist ground, usually in a forest. Some species are aquatic throughout life, some take to the water intermittently, and some are entirely terrestrial as adults. Salamanders superficially resemble lizards, but are easily distinguished by their lack of scales. They are capable of regenerating lost limbs.

A blastema is a mass of undifferentiated cells capable of growth and regeneration into organs or body parts. Blastemata are typically found in the early stages of an organism's development such as in embryos, and in the regeneration of tissues, organs and bone.

http://www.faculty.uci.edu/profile.cfm?faculty_id=4614

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Sunday, February 25, 2007

Einstein's Big Idea

http://www.pbs.org/wgbh/nova/einstein/
http://physics.physorg.com/


While searching for "Twin Paradox" solved by Indian scientist Subhash Kak, I landed on the above site.

http://www.physorg.com/news90697187.html

Subhash Kak, Delaune Distinguished Professor of Electrical and Computer Engineering at LSU, recently resolved the twin paradox, known as one of the most enduring puzzles of modern-day physics.

First suggested by Albert Einstein more than 100 years ago, the paradox deals with the effects of time in the context of travel at near the speed of light. Einstein originally used the example of two clocks – one motionless, one in transit. He stated that, due to the laws of physics, clocks being transported near the speed of light would move more slowly than clocks that remained stationary.

In more recent times, the paradox has been described using the analogy of twins. If one twin is placed on a space shuttle and travels near the speed of light while the remaining twin remains earthbound, the unmoved twin would have aged dramatically compared to his interstellar sibling, according to the paradox.

“If the twin aboard the spaceship went to the nearest star, which is 4.45 light years away at 86 percent of the speed of light, when he returned, he would have aged 5 years. But the earthbound twin would have aged more than 10 years!” said Kak.

The fact that time slows down on moving objects has been documented and verified over the years through repeated experimentation. But, in the previous scenario, the paradox is that the earthbound twin is the one who would be considered to be in motion – in relation to the sibling – and therefore should be the one aging more slowly. Einstein and other scientists have attempted to resolve this problem before, but none of the formulas they presented proved satisfactory.

Kak’s findings were published online in the International Journal of Theoretical Physics, and will appear in the upcoming print version of the publication. “I solved the paradox by incorporating a new principle within the relativity framework that defines motion not in relation to individual objects, such as the two twins with respect to each other, but in relation to distant stars,” said Kak. Using probabilistic relationships, Kak’s solution assumes that the universe has the same general properties no matter where one might be within it.

The implications of this resolution will be widespread, generally enhancing the scientific community’s comprehension of relativity. It may eventually even have some impact on quantum communications and computers, potentially making it possible to design more efficient and reliable communication systems for space applications.

kak@ece.lsu.edu

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Tuesday, February 20, 2007

Project MetaCat

http://www.cs.pomona.edu/~marshall/metacat/dissertation.pdf

Metacat: A Self-Watching Cognitive Architecture for Analogy-Making and High-Level Perception

Traditionally, researchers working on the computational modeling of analogy have
tended to view analogy-making as a special type of thinking useful for solving prob-
lems via the technique of analogical reasoning. According to this view, a good way to
solve a given problem is often by recourse to a similar problem that one has encoun-
tered and solved previously. By setting up an analogy between the previous problem
and the current problem, and using the previous solution as a guide, one can often
discover a solution to the problem at hand. This type of reasoning is often used by students when trying to work through scientifc or mathematical problems in textbooks. Typically, a worked-out example in the text, similar to the problem to be solved, is frst identifed (the more similar, the better). The worked-out example solution is then applied to the corresponding elements of the new problem (hopefully without too much modifcation required), yielding a solution.

What made me post above para is I found a smilarity in my thought process and above para (though not exact) as I always say that "When we solve some problem, handle some project / work..etc. in our life and face a failure, there is nothing to get disappointed and depressed on it as I believe that depression leads to lac of self confidence in oneself and topples the whole identity of a person. Instead, what we need to do is analyze our past work and identify a smallest success in what we have done. Though we have reached a failure, we might have done some part of it successfully, though its small, it keeps your morale high, next identify those what lead to its failure...keep them as experience and when you do next project, try not to do those what you have done and failed already...apply different methods and ways to achieve it."

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Bose-Einstein Condensation (BEC)

http://www.colorado.edu/physics/2000/bec/

Bose-Einstein Condensation in a gas: a new form of matter at the coldest temperatures in the universe...

http://www.thecrimson.com/article.aspx?ref=516971

Predicted 1924... ...Created 1995

Physicists at Harvard have discovered a “quantum-mechanical magic trick” by finding a way to stop a pulse of light in one part of space and make it reappear two tenths of a millimeter away, according to researchers at the University’s Hau Laboratory.

Led by Mallinckrodt Professor of Physics Lene V. Hau, the experiment involved firing lasers through two clouds of sodium atoms cooled to a few billionths of a degree above absolute zero.

At such cold temperatures the atoms’ motions are virtually halted, and they begin to behave more like waves than particles.

Featured in the Feb. 8 issue of Nature, the study showed that once a laser pulse is shot into one sodium cloud—known as a Bose-Einstein condensate (BEC)—it is signficantly compressed and deccelerated.

“The light pulse is slowed from 186,000 miles per second to 15 miles per hour, and is also spatially compressed from 1 kilometer to less than half the width of a hair,” Hau wrote in an e-mail.

From the beginning of the experiment, a control laser is continually fired through the BECs. When the experimental laser pulse enters the first BEC traveling in the opposite direction of the control laser, a matter imprint is made and both lasers are manually shut off.

Even with both lasers discontinued, the matter imprint continues to travel at 700 feet per hour through the cloud, exiting the first BEC, continuing on through free space, and ultimately entering the second BEC.

The control laser is then rekindled and the laser pulse is revived and exits the second BEC at its original speed of 186,000 miles per second, Hau explained.

According to Hau, who collaborated with research assistant Naomi S. Ginsberg and post-doctoral fellow Sean R. Garner on the study, matter is easier to manipulate than light, which implies many future applications of their discovery.

When the light pulse is in a matter state between BECs, “we can grab it with a laser beam—put it on the shelf so to speak—and later let it back on its way and revive it in the second BEC,” Hau said. During this “shelved” period, the matter wave can be manipulated by physicists and will preserve any changes when it is revived again as a laser.

In particular, these maniuplations can potentially be used in the processing and encoding of optical information, Hau said.

Data could be sent along optical fibers, much like what many internet service providers use to facilitate internet communication, and be manipulated in the process by using the sodium clouds.

According to Hau, the system could also be applied to quantum information networks.

---------------------------------------------

More info found at http://www.physorg.com/news90077438.html

Physicists have for the first time stopped and extinguished a light pulse in one part of space and then revived it in a completely separate location. They accomplished this feat by completely converting the light pulse into matter that travels between the two locations and is subsequently changed back to light.

Two years later, she brought light to a complete halt in a cloud of ultracold atoms. Next, she restarted the stalled light without changing any of its characteristics, and sent it on its way. These highly successful experiments brought her a tenured professorship at Harvard University and a $500,000 MacArthur Foundation award to spend as she pleased.

Now Mallinckrodt Professor of Physics and of Applied Physics, Hau has done it again. She and her team made a light pulse disappear from one cold cloud then retrieved it from another cloud nearby. In the process, light was converted into matter then back into light. For the first time in history, this gives science a way to control light with matter and vice versa.

It's a thing that most scientists never thought was possible. Some colleagues had asked Hau, "Why try that experiment? It can't be done."

In the experiment, a light pulse was slowed to bicycle speed by beaming it into a cold cloud of atoms. The light made a "fingerprint" of itself in the atoms before the experimenters turned it off. Then Hau and her assistants guided that fingerprint into a second clump of cold atoms. And get this - the clumps were not touching and no light passed between them.

"The two atom clouds were separated and had never seen each other before," Hau notes. They were eight-thousandths of an inch apart, a relatively huge distance on the scale of atoms.

The experimenters then nudged the second cloud of atoms with a laser beam, and the atomic imprint was revived as a light pulse. The revived light had all the characteristics present when it entered the first cloud of atomic matter, the same shape and wavelength. The restored light exited the cloud slowly then quickly sped up to its normal 186,000 miles a second.

Communicating by light

Light carries information, so think of information being manipulated in ways that have never before been possible. That information can be stored - put on a shelf, so to speak - retrieved at will, and converted back to light. The retrieved light would contain the same information as the original light, without so much as a period being lost.

Or the information could be changed. "The light waves can be sculpted," is the way Hau puts it. "Then it can be passed on. We have already observed such re-sculpted light in our lab."

A weird thing happens to the light as it enters the cold atomic cloud, called a Bose-Einstein condensate. It becomes squeezed into a space 50 million times smaller. Imagine a light beam 3,200 feet (one kilometer) long, loaded with information, that now is only a hair width in length but still encodes as much information.

From there it becomes easier to imagine new types of computers and communications systems - smaller, faster, more reliable, and tamper-proof.

Atoms at room temperature move in a random, chaotic way. But when chilled in a vacuum to about 460 degrees below zero Fahrenheit, under certain conditions millions of atoms lock together and behave as a single mass. When a laser beam enters such a condensate, the light leaves an imprint on a portion of the atoms. That imprint moves like a wave through the cloud and exits at a speed of about 700 feet per hour. This wave of matter will keep going and enter another nearby ultracold condensate. That's how light moves darkly from one cloud to another in Hau's laboratory.

This invisible wave of matter keeps going unless it's stopped in the second cloud with another laser beam, after which it can be revived as light again.

Atoms in matter waves exist in slightly different energy levels and states than atoms in the clouds they move through. These energy states match the shape and phase of the original light pulse. To make a long story short, information in this form can be made absolutely tamper proof. Personal information would be perfectly safe.

Such a light-to-matter, matter-to-light system "is a wonderful thing to wrap your brain around," Hau muses.

Details of the experiments appear as the cover story of the Feb. 8 issue of Nature. Authors of the report include graduate student Naomi Ginsberg, postdoctoral fellow Sean Garner, and Hau.

In a practical manner

You won't see a light-matter converter flashing away in a factory, business, or mall anytime soon. Despite all the intriguing possibilities, "there are no immediate practical uses," Hau admits.

However, she has no doubt that practical systems will come. And when they do, they will look completely different from anything we are familiar with today. They won't need a lot of wires and electronics. "Instead of light shining through optical fibers into boxes full of wires and semiconductor chips, intact data, messages, and images will be read directly from the light," Hau imagines.

Creating those ultracold atomic clouds in a factory, office, or recreation room will be a problem, but one she believes can be solved. "The atomic clouds we use in our lab are only a tenth of a millimeter (0.004 inch) long," she points out. "Such atom clouds can be kept in small containers, not all of the equipment has to be so cold. Most likely, a practical system designed by engineers will look totally unlike the setup we have in our lab today."

There are no "maybes" in Hau's voice. She is coolly confident that light-to-matter communication networks, codes, clocks, and guidance systems can be made part of daily life. If you doubt her, remember she is the person who stopped light, converted it to matter, carried it around, and transformed it back to light.

Source: Harvard University, by William J. Cromie

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Lagrangian point



The Lagrangian points or also Lagrange point, L-point, or libration point, are the five positions in an orbital configuration where a small object affected only by gravity can theoretically be stationary relative to two larger objects (such as a satellite with respect to the Earth and Moon). The Lagrange points mark positions where the combined gravitational pull of the two large masses provides precisely the centripetal force required to rotate with them. They are analogous to geosynchronous orbits in that they allow an object to be in a "fixed" position in space rather than an orbit in which its relative position changes continuously.

A more precise but technical definition is that the Lagrangian points are the stationary solutions of the circular restricted three-body problem. For example, given two massive bodies in circular orbits around their common center of mass, there are five positions in space where a third body, of comparatively negligible mass, could be placed which would then maintain its position relative to the two massive bodies. As seen in a frame of reference which rotates with the same period as the two co-orbiting bodies, the gravitational fields of two massive bodies combined with the centrifugal force are in balance at the Lagrangian points, allowing the third body to be stationary with respect to the first two bodies.

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Tuesday, February 06, 2007

Over 100 fossilised eggs of dinosaur found in MP



Geological Survey of India's former Director Arun Sonakia shows fossilized eggs of dinosaurs to media persons at Mandav, around 280 kilometers (175 miles) west of Bhopal, India on Monday. Explorers have stumbled upon more than 100 fossilized eggs of dinosaurs belonging to the Cretaceous Era (approximately 144 to 65 million years ago), in Kukshi-Bagh area of Dhar district, of Madhya Pradesh according to a newspaper report.


Article on Hindustan Times
http://www.hindustantimes.com/news/181_1920136,00040009.htm

Over 100 fossilised eggs of dinosaur found in MP

Nivedita Khandekar

Indore, February 5, 2007

In a remarkable feat, three amateur explorers have stumbled upon more than 100 fossilised eggs of dinosaurs in Madhya Pradesh. The eggs, belonging to the Cretaceous Era (approximately 144 to 65 million years ago), have been discovered in Kukshi-Bagh area of Dhar district, some 150 kms south-west of Indore.

The rare find is a significant step in the study of pre-historic life in the Narmada Valley.

"All the eggs were discovered from a single nesting site in a start to end exploration for 18 hours at the site in Kukshi-Bagh area, 40 kms from Manavar. As many as 6-8 eggs were found per nests," an excited Vishal Verma of the Mangal Panchayatan Parishad, a group of amateur explorers, told Hindustan Times from near the site.

"The eggs are from upper cretaceous era when the dinosaurs were yet to be extinct. These eggs can be categorised in three types of soropaud dinosaurs, which were herbivorous. These animals used to come from far away areas to lay eggs on the sandy banks of the rivers in this area, identified scientifically as Lameta bed," Verma said.
The dinosaurs were 40-90 feet in length, he added.

Along with the fossilised eggs, the team - comprising two other members Rajesh Chouhan and Govind Verma - also discovered footprints of the dinosaurs through which they could also trace the 'track way' of the heavy animals now extinct.

Geological Survey of India's former Director (Palaeontology) Dr Arun Sonakia who was also at the site of the find told this correspondent over telephone, "It's a good job done by amateurs. With this find, the scientists would be able to know more about the spread of the dinosaurs. It can also throw light on the reasons of extinction."
"Plus the nesting sites and large number of fossilised eggs would also throw light on the variety of dinosaurs that existed in the cretaceous era," Sonakia added.

The Parishad had earlier discovered fossilised bones of the dinosaurs in the region.

• The richest dinosaur field in India is in the "Deccan Traps" near Jabalpur in Madhya Pradesh.

• About 65 million years ago, a huge mass of volcanic rock erupted from the earth, covering 500,000 sq km in Maharashtra and MP with lava 2 km high. This is exactly the time when all large dinosaur species became extinct.

• A small but ferocious dinosaur, about the size of adult humans, was named Jubbulpuria after it was found in Jabalpur by Matley in 1933.

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