28 jun. 2005

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27 jun. 2005

Curioso...

Space station gets HAL-like computer

A voice-operated computer assistant is set to be used in space for the first time on Monday – its operators hope it proves more reliable than "HAL", the treacherous speaking computer in the movie 2001.
Called Clarissa, the program will initially talk astronauts on the International Space Station through tests of onboard water supplies. But its developers hope it will eventually be used for all computer-related work on the station.
Clarissa was designed with input from astronauts. They said it was difficult to perform the 12,000 procedures necessary to maintain the ISS and conduct scientific experiments while simultaneously reading through lengthy instruction manuals.
"Just try to analyse a water sample while scrolling through pages of a procedure manual displayed on a computer monitor while you and the computer both float in microgravity," says US astronaut Michael Fincke, who spent six months on the station in 2004.
Clarissa queries astronauts about the details of what they need to accomplish in a particular procedure, then reads through step-by-step instructions. Astronauts control the program using simple commands like "next" or more complicated phrases, such as "set challenge verify mode on steps three through fourteen".
"The idea was to have a system that would read steps to them under their control, so they could keep their hands and eyes on whatever task they were doing," says Beth Ann Hockey, a computer scientist who leads the project at NASA's Ames Research Center in Moffett Field, California, US.
That capability "will be like having another crew member aboard", says Fincke. (You can see Clarissa in action in a mp4 video hosted on this NASA page.)
“No, I meant … “
Clarissa's software runs on a laptop and astronauts interact with it using a headset, which helps screen out noise from the station. The program "listens" to everything astronauts say and analyses what to do in response using a "command grammar" of 75 commands based on a vocabulary of 260 words.
It accurately interprets those commands about 94% of the time, but if it makes a mistake, astronauts can correct it with commands like, "no, I meant … ". But because Clarissa listens to everything, early versions of the program misinterpreted whether an astronaut was giving it a command or having an unrelated conversation about 10% of the time.
So developers turned to the Xerox Research Centre Europe in Grenoble, France, and researchers there halved that error rate by using the context of phrases as a "spam-filtering system", says Manny Rayner, Clarissa's lead implementer at NASA Ames.
Clarissa's software was delivered to the station in January 2005 and on Monday, US astronaut John Phillips, currently aboard the station, will train to use the program in space.
It currently covers a handful of procedures designed to test station water for bacteria. But project managers hope the protocol can be applied to other procedures - and eventually could be used to launch any computer application. "Ultimately, we'd like speaking to your computer to be normal," Hockey told New Scientist.
That might send shivers down the spine of anyone who watched HAL turn on its human controllers in Stanley Kubrick's "2001: A Space Odyssey". But Hockey says Clarissa does not have HAL's artificial intelligence. "Clarissa is more friendly and is not going to go renegade on us," says Hockey, whose recorded voice has been borrowed by Clarissa.

Boffins create zombie dogs

NEWS.com.au

SCIENTISTS have created eerie zombie dogs, reanimating the canines after several hours of clinical death in attempts to develop suspended animation for humans.

US scientists have succeeded in reviving the dogs after three hours of clinical death, paving the way for trials on humans within years.

22 jun. 2005

Quantum Calculation

Computers have infiltrated nearly every field of business and science, and they keep getting faster. Nonetheless, researchers routinely encounter problems impossible for even the most powerful supercomputers to solve. The remedy could be quantum computers, which would use the fantastic properties of quantum mechanics to crack such problems in seconds rather than centuries. Since the 1980s, physicists in academic labs and at firms such as IBM, Hewlett-Packard, and NEC have pursued a variety of quantum computing approaches, but none seems likely to deliver a working machine in less than 10 years.
Company: D-Wave Systems
Headquarters: Vancouver, British Columbia
Amount invested: $22 million Canadian (about $17.5 million U.S.)
Lead investor: Draper Fisher Jurvetson
Key founders: Geordie Rose, Alexandre Zagoskin, Bob Wiens, Haig Farris
Technology: Quantum computers
Vancouver startup D-Wave Systems, however, aims to build a quantum computer within three years. It won't be a fully functional quantum computer of the sort long envisioned; but D-Wave is on track to produce a special-purpose, "noisy" piece of quantum hardware that could solve many of the physical-simulation problems that stump today's computers, says David Meyer, a mathematician working on quantum algorithms at the University of California, San Diego.
The difference between D-Wave's system and other quantum computer designs is the particular properties of quantum mechanics that they exploit. Other systems rely on a property called entanglement, which says that any two particles that have interacted in the past, even if now spatially separated, may still influence each other's states. But that interdependence is easily disrupted by the particles' interactions with their environment. In contrast, D-Wave's design takes advantage of the far more robust property of quantum physics known as quantum tunneling, which allows particles to "magically" hop from one location to another.
Incorporated in April 1999, D-Wave originated as a series of conversations among students and lecturers at the University of British Columbia. Over the years, it has amassed intellectual property and narrowed its focus, while attracting almost $18 million in funding, initially from angel investors and more recently from the Canadian and German governments, and from venture capital firms. The company plans to complete a prototype device by the end of 2006; a version capable of solving commercial problems could be ready by 2008, says president and CEO Geordie Rose.
The aggressiveness of D-Wave's timetable is made possible by the simplicity of its device's design: an analog chip made of low-temperature superconductors. The chip must be cooled to -269 °C with liquid helium, but it doesn't require the delicate state-of-the-art lasers, vacuum pumps, and other exotic machinery that other quantum computers need.
The design is also amenable to the lithography techniques used to make standard computer chips, further simplifying fabrication. D-Wave patterns an array of loops of low-temperature superconductors such as aluminum and niobium onto a chip. When electricity flows through them, the loops act like tiny magnets. Two refrigerator magnets will naturally flip so that they stick together, minimizing the energy between them. The loops in D-Wave's chip behave similarly, "flipping" the direction of current flow from clockwise to counterclockwise to minimize the magnetic flux between them. Depending on the problem it's meant to tackle, the chip is programmed so that current flows through each loop in a particular direction. The loops then spontaneously flip until they reach a stable energy state, which represents the solution to the problem.
D-Wave's first computer won't be able to accomplish the most widely touted payoff of quantum computing: factoring the extremely large numbers at the heart of modern cryptographic systems exponentially faster than any known computer. It will, however, be ideally suited to solving problems like the infamous traveling-salesman problem, in which a salesman searches for the optimal route among cities. As their complexity grows, such problems quickly become intractable for traditional computers because they require investigating every possible answer. In searching for its own optimal energy state, D-Wave's chip performs exactly this type of calculation automatically, in seconds. Applications--some worth billions of dollars--include optimizing such varied items as truck routes, financial portfolios, and even the layouts of traditional computer chips. D-Wave collaborator Oliver Downs says D-Wave's chip should also excel at modeling other quantum systems, such as the molecular interactions that characterize nanomaterials or drugs.
Although more robust than typical quantum computers, D-Wave's systems will still be delicate. So the firm intends to sell solutions rather than computers, says Rose. A customer will run a program to solve a given problem on its own computers. When the program encounters the "unsolvable" part of the problem, it will remotely call D-Wave's computer to run a subroutine. "For many specialized applications, such dedicated hardware has the potential to be superior to even the most clever software running on a general-purpose computer," says UCSD's Meyer.
And while many approaches to quantum computing have hit a wall, butting up against the limits of lasers and other equipment, Downs believes that D-Wave's early experimental results indicate that its chip is right on schedule. Although Meyer says he can't assess whether the company will meet its self-imposed deadlines, he believes it will succeed in building a machine that can solve exactly the sorts of problems it envisions. "They've employed both very good experimentalists and some pretty serious theory people," he says. "That's certainly the way to approach this kind of problem to make it happen in nonacademic amounts of time."
Company: D-Wave Systems
Headquarters: Vancouver, British Columbia
Amount invested: $22 million Canadian (about $17.5 million U.S.)
Lead investor: Draper Fisher Jurvetson
Key founders: Geordie Rose, Alexandre Zagoskin, Bob Wiens, Haig Farris
Technology:Quantum computers

17 jun. 2005

No paradox for time travellers

THE laws of physics seem to permit time travel, and with it, paradoxical situations such as the possibility that people could go back in time to prevent their own birth. But it turns out that such paradoxes may be ruled out by the weirdness inherent in laws of quantum physics.

Some solutions to the equations of Einstein's general theory of relativity lead to situations in which space-time curves back on itself, theoretically allowing travellers to loop back in time and meet younger versions of themselves. Because such time travel sets up paradoxes, many researchers suspect that some physical constraints must make time travel impossible. Now, physicists Daniel Greenberger of the City University of New York and Karl Svozil of the Vienna University of Technology in Austria have shown that the most basic features of quantum theory may ensure that time travellers could never alter the past, even if they are able to go back in time.

The constraint arises from a quantum object's ability to behave like a wave. Quantum objects split their existence into multiple component waves, each following a distinct path through space-time. Ultimately, an object is usually most likely to end up in places where its component waves recombine, or "interfere", constructively, with the peaks and troughs of the waves lined up, say. The object is unlikely to be in places where the components interfere destructively, and cancel each other out.

Quantum theory allows time travel because nothing prevents the waves from going back in time. When Greenberger and Svozil analysed what happens when these component waves flow into the past, they found that the paradoxes implied by Einstein's equations never arise. Waves that travel back in time interfere destructively, thus preventing anything from happening differently from that which has already taken place (www.arxiv.org/quant-ph/0506027). "If you travel into the past quantum mechanically, you would only see those alternatives consistent with the world you left behind you," says Greenberger.

"This is a very nice idea," says physicist Avshalom Elitzur of the Weizmann Institute in Rehovot, Israel, who also suggests that further work in the area could help to clarify the nature of time itself. "Time is a very mysterious thing."

Los amigos ayudan a vivir más

BBC.co.uk

Los buenos amigos son aquellos que están siempre allí, para compartir los buenos momentos y para dar una mano cuando se los necesita. También están allí para ayudar a vivir más años.

15 jun. 2005

Entrenamiento para el cerebro

BBC.co.uk

Un estudio científico sugiere que las respuestas básicas e involuntarias del cerebro pueden ser anuladas.

A esta conclusión llegaron los expertos de las universidades de Queensland y California luego de estudiar las reacciones visuales de 76 monjes budistas tibetanos con experiencia en meditación.

7 jun. 2005

REVOLUTIONARY UNDERWATER BREATHING SYSTEM

LIKE A FISH –
REVOLUTIONARY UNDERWATER BREATHING SYSTEM

An Israeli Inventor has developed a breathing apparatus that will allow breathing underwater without the assistance of oxygen tanks. This new invention will use the relatively small amounts of air that already exist in water to supply oxygen to both scuba divers and submarines. The invention has already captured the interest of most major diving manufacturers as well as the Israeli Navy.

The idea of breathing underwater without cumbersome oxygen tanks has been the dream of science fiction writers for many years. In George Lucas’ movie "The Phantom Menace", Obi-Wan whips out a little Jedi underwater breathing apparatus and dives in. As things tend to happen in our world, yesterday’s science fiction has turned into today's science fact due to one Israeli inventor with a dream.

There are a number of limitations to the existing oxygen tank underwater breathing method. The first is the amount of time a diver can stay underwater, which is the result of the oxygen tank capacity. Another limitation is the dependence on oxygen refueling facilities near the diving site which are costly to operate and are used to compress the gas into the tanks which might be dangerous if not handled properly. The final problem has to do with the actual use of oxygen tanks underwater. When these tanks are in use they empty out and change the balance of the diver in the water.

Engineers have tried to overcome these limitations for many years now. Nuclear submarines and the international space station use systems that generate Oxygen from water by performing 'Electrolysis', which is chemical separation of Oxygen from Hydrogen. These systems require very large amounts of energy to operate. For this reason, smaller, diesel fueled submarines cannot use these systems and are required to resurface to re-supply their oxygen tanks every so often. Divers can't even consider carrying such large machines not to mention supplying them with energy. To overcome this limitation an Israeli inventor, Alon Bodner, turned to fish.
Fish do not perform chemical separation of oxygen from water; instead they use the dissolved air that exists in the water in order to breathe. In the ocean the wind, waves and underwater currents help spread small amounts of air inside the water. Studies have shown that in a depth of 200m below the sea there is still about 1.5% of dissolved air. This might not sound like much but it is enough to allow both small and large fish to breathe comfortably underwater. Bodner’s idea was to create an artificial system that will mimic the way fish use the air in the water thus allowing both smaller submarines and divers to get rid of the large, cumbersome oxygen tanks.

The system developed by Bodner uses a well known physical law called the "Henry Law" which describes gas absorption in liquids. This law states that the amount of gas that can be dissolved in a liquid body is proportional to the pressure on the liquid body. The law works in both directions – lowering the pressure will release more gas out of the liquid. This is done by a centrifuge which rotates rapidly thus creating under pressure inside a small sealed chamber containing sea water. The system will be powered by rechargeable batteries. Calculations showed that a one kilo Lithium battery can provide a diver with about one hour of diving time.

Bodner has already built and tested a laboratory model and he is on the path to building a full-scale prototype. Patents for the invention have already been granted in Europe and a similar one is currently pending examination in the U.S. Meetings have already been held with most major diving manufacturers as well as with the Israeli Navy. Initial financial support for the project has been given by Israel Ministry of Industry and Commerce and Bodner is currently looking for private investors to help complete his project.

If everything goes according to plan, in a few years the new tankless breathing system will be operational and will be attached to a diver in the form of a vest that will enable him to stay underwater for a period of many hours.

4 jun. 2005

Ten Most Harmful Books of the 19th and 20th Centuries

HUMAN EVENTS ONLINE

HUMAN EVENTS asked a panel of 15 conservative scholars and public policy leaders to help us compile a list of the Ten Most Harmful Books of the 19th and 20th Centuries. Each panelist nominated a number of titles and then voted on a ballot including all books nominated. A title received a score of 10 points for being listed No. 1 by one of our panelists, 9 points for being listed No. 2, etc. Appropriately, The Communist Manifesto, by Karl Marx and Friedrich Engels, earned the highest aggregate score and the No. 1 listing.

3 jun. 2005

El universo en un computador

Un equipo internacional de astrofísicos recreó la evolución del Universo en una supercomputadora.

Se trata de la mayor simulación que se haya intentado para investigar los cambios en la estructura del cosmos.

Los científicos, del Reino Unido, Alemania, Canadá y Estados Unidos utilizaron 25 millones de megabytes de memoria en una supercomputadora en Garching, Alemania, que tardó un mes ininterrumpido en configurar la simulación.

"Se trata posiblemente de lo más grande en física computarizada. Tenemos una réplica del Universo muy parecida al Universo real. Ahora podemos empezar a experimentar, por primera vez, con el Universo", dijo el profesor Carlos Frenk, de la Universidad de Durham, en el norte de Inglaterra, uno de los autores de la investigación.

La misteriosa energía negra

La simulación rastrea cerca de 14.000 años en la historia del cosmos y se espera que ayude a comprender uno de los grandes misterios del Universo, la llamada "energía negra".

Las estrellas, galaxias, los agujeros negros y su radiación conforman una pequeña parte del cosmos. Más del 70% del Universo está compuesto por la "energía negra", una fuerza que actúa en forma contraria a la gravedad y que parece estar impulsando al cosmos.

De acuerdo a Frenk, la naturaleza de la energía negra es "el problema número uno sin resolver de la Física, si no de la ciencia en general".

"Nuestras simulaciones nos muestran donde buscar pistas para estudiar la energía negra. Si queremos aprender sobre esta energía, debemos estudiar especialmente los conglomerados o grupos de galaxias", agrega Frenk.

El trabajo del equipo internacional de astrofísicos está detallado en un artículo que publica este jueves la revista Nature.

2 jun. 2005

After 'Deep Throat,' what mysteries remain?

Now that "Deep Throat" has been identified as a 91-year-old California grandfather, aficionados of unsolved mysteries have to look elsewhere. Luckily for them, there are plenty of places to look.

Even after Tuesday's revelation that former FBI No. 2 Mark Felt was the Watergate super-source "Deep Throat," there are still unknowns swirling around the scandal that brought down President Richard Nixon in 1974.

The main question remaining is what information was contained -- and erased -- in the 18 1/2 minute gap in a White House tape recording. The tape, made by Nixon's secretary, Rose Mary Woods, contained a discussion between the president and his chief of staff, H.R. Haldeman, pertaining to Watergate.

Woods shot to notoriety for her inadequate explanations of how she came to erase part of the tape. She never told what the tape held before her death on Jan. 22.

A more contemporary Washington mystery is the source of the leak that led columnist Robert Novak to identify a CIA operative named Valerie Plame, an expert on weapons of mass destruction.

Novak mentioned Plame by name in a July 14, 2003, column critical of Plame's husband, retired diplomat Joseph Wilson, after Wilson reported an Iraqi purchase of uranium "yellowcake" from Niger was highly unlikely. Wilson's report went counter to some in the Bush administration who sought a link between Iraq and weapons of mass destruction.

Novak has not said where he got the information, but denied it was a "planned leak," and said he was never told revealing Plame's identity would endanger her or anyone else. A special prosecutor is investigating the case.

CHANDRA LEVY AND D.B. COOPER

The mystery that set Washingtonians buzzing in the summer of 2001 was the disappearance of 24-year-old Chandra Levy, a government intern who had a relationship with Rep. Gary Condit, a California Democrat. Levy's skeletal remains were found in a city park in 2002. How they got there remains unknown.

Beyond Washington, there are historical mysteries that still resonate. Many observers wonder whether Lee Harvey Oswald acted alone on Nov. 22, 1963, when President John F. Kennedy was assassinated in Dallas.

Conspiracy theories surrounding the assassination, some featured in popular movies, have focused on the possible involvement of groups ranging from the Mafia to anti-Castro Cuban exiles and the CIA. Questions have also been raised about what motivated Jack Ruby to kill Oswald in a Dallas police station two days after the assassination.

The mystery surrounding former Teamsters union leader Jimmy Hoffa revolves around what happened to his body after he disappeared from a Michigan parking lot in 1975. The presumption is he was killed by the Mafia, but the whereabouts of his remains are unknown.

The final fate of pioneer aviator Amelia Earhart has never been discovered, although theories abound. She was last heard from on July 2, 1937, on the Pacific leg of her attempt to be the first woman to fly around the globe. Extensive rescue attempts turned up nothing.

Other disappearances that piqued mystery-lovers' interest include D.B. Cooper, who hijacked a commercial airliner in 1971, extorted $200,000 from its owner and then leaped from the plane with 21 pounds (9.5 kg) of $20 bills strapped to his body. He has never been seen again, and his real identity remains unknown.

"The Missingest Man In New York" was state Supreme Court Judge Joseph Crater, who seemingly vanished after hailing a cab on a New York street on Aug. 6, 1930. He was officially declared dead in 1939, but sightings of the dandified jurist continued for years.

¿Qué mató la mega fauna?

Es poco probable que los seres humanos hayan sido los responsables de la desaparición de los grandes mamíferos que alguna vez vivieron en las vastas planicies australianas.

Nuevos estudios sugieren que, si bien la acción humana fue un factor influyente, el principal factor en la desaparición de los animales fue el cambio climático.

Hace unos 45.000 años Australia era el hogar de seres vivos como el impresionante Thylacoleo Carnifex , un león marsupial de grandes colmillos; el Diprotodon optatum, que tenía el tamaño de un hipopótamo, y el Megalania prisca , un lagarto de 400 kilos.

La desaparición de estos animales tuvo lugar rápidamente, en un período de 1.000 años aproximadamente y coincidió con la llegada de los seres humanos al área.

Hasta ahora se había sostenido que los seres humanos habían causado la extinción de la mega fauna, a través de la caza o de la destrucción del habitat natural mediante incendios.

Los científicos señalan que el factor determinante de la extinción fue la caída brusca en temperaturas y la transformación de grandes extensiones verdes en zonas áridas.

Frío y árido

Uno de los estudios, realizado por Clive Trueman, de la Universidad de Portsmouth, en Inglaterra y colegas en Australia, se basa en el análisis de fósiles hallados en Cuddie Springs, en Nueva Gales del Sur.

Los especímenes sugieren que los humanos y la mega fauna convivieron durante un período de al menos 10.000 años.

Un segundo estudio, de Gilbert Price, de la Universidad de Tecnología de Queensland, plantea la misma hipótesis del cambio climático.

Price asegura que el cambio a un clima más seco y más árido que tuvo lugar hace entre 50.000 y 20.000 años modificó las condiciones necesarias para sobrevivir.

Por otra parte, registros de radio-carbono permitieron determinar que los fósiles estudiados, recogidos en el sureste de Queensland, datan de un período anterior a la llegada de los primeros seres humanos a la región, según Price.

Los nuevos estudios fueron publicados esta semana en la revista de la Academia Nacional de Ciencias de Australia (PNAS) y en los Anales del Museo de Queensland.