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Dwarf galaxies provide new insights on dark matter

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(Apr. 2, 2012) — There's more to the cosmos than meets the eye. About 80 percent of the matter in the universe is invisible to telescopes, yet its gravitational influence is manifest in the orbital speeds of stars around galaxies and in the motions of clusters of galaxies. Yet, despite decades of effort, no one knows what this "dark matter" really is. Many scientists think it's likely that the mystery will be solved with the discovery of new kinds of subatomic particles, types necessarily different from those composing atoms of the ordinary matter all around us. The search to detect and identify these particles is underway in experiments both around the globe and above it.

Scientists working with data from NASA's Fermi...

Graphene membranes: First controllable use of scanning tunneling microscopy on freestanding graphene

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(Apr. 2, 2012) — Graphene could be the superhero of materials -- it's light, strong and conducts heat and electricity effectively, which makes it a great material for potential use in all kinds of electronics. And because it's made from carbon atoms, graphene is cheap and plentiful. Its electric and mechanical properties also affect one another in unique ways. But before freestanding graphene can live up to its potential, scientists need to be able to control these...

New light shed on catalytic reactions used by plants to split oxygen from water

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(Apr. 2, 2012) — Splitting hydrogen and oxygen from water using conventional electrolysis techniques requires considerable amounts of electrical energy. But green plants produce oxygen from water efficiently using a catalytic technique powered by sunlight -- a process that is part of photosynthesis and so effective that it is Earth's major source of oxygen.

If mimicked by artificial systems, this photocatalytic process could provide abundant new supplies of oxygen and, possibly...

Self-sculpting sand: Heaps of 'smart sand’ could assume any shape, form new tools or duplicatie broken parts

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(Apr. 2, 2012) — Imagine that you have a big box of sand in which you bury a tiny model of a footstool. A few seconds later, you reach into the box and pull out a full-size footstool: The sand has assembled itself into a large-scale replica of the model.

That may sound like a scene from a Harry Potter novel, but it's the vision animating a research project at the Distributed Robotics Laboratory (DRL) at MIT's Computer Science and Artificial Intelligence Laboratory. At the IEEE...

Scientists track radioactive iodine in New Hampshire from Japan nuclear reactor meltdown

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(Apr. 2, 2012) — Radioactive iodine found by Dartmouth researchers in the local New Hampshire environment is a direct consequence of a nuclear reactor's explosion and meltdown half a world away, says Joshua Landis, a research associate in the Department of Earth Science. The failure of the Fukushima Daiichi nuclear power facility, following the March 11, 2011, earthquake and tsunami, was the largest nuclear disaster since 1986 at Chernobyl. "We live on a really small planet and this...

New quantum encryption method foils hackers

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(Apr. 2, 2012) — A research team led by University of Toronto Professor Hoi-Kwong Lo has found a new quantum encryption method to foil even the most sophisticated hackers. The discovery is outlined in the latest issue of Physical Review Letters.

Quantum cryptography is, in principle, a foolproof way to prevent hacking. It ensures that any attempt by an eavesdropper to read encoded communication data will lead to disturbances that can be detected by the legitimate users...

Images capture split personality of dense suspensions

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(Mar. 30, 2012) — Stir lots of small particles into water, and the resulting thick mixture appears highly viscous. When this dense suspension slips through a nozzle and forms a droplet, however, its behavior momentarily reveals a decidedly non-viscous side. University of Chicago physicists recorded this surprising behavior in laboratory experiments using high-speed photography, which can capture action taking place in one hundred-thousandths of a second or less.

UChicago...

Honeycombs of magnets could lead to new type of computer processing

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(Mar. 30, 2012) — Scientists have taken an important step forward in developing a new material using nano-sized magnets that could ultimately lead to new types of electronic devices, with greater processing capacity than is currently feasible, in a study published recently in the journal Science.

Many modern data storage devices, like hard disk drives, rely on the ability to manipulate the properties of tiny individual magnetic sections, but their overall design is limited by...

Microprocessors from graphene: Discoveries may advance electronic circuit technology

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(Mar. 30, 2012) — Graphene could become the next big thing in the quest for smaller, less power-hungry electronics. Physicists are making discoveries that may advance electronic circuit technology.

Resembling chicken wire on a nano scale, graphene -- single sheets of graphite -- is only one atom thick, making it the world's thinnest material. Two million graphene sheets stacked up would not be as thick as a credit card.

The tricky part physicists have yet to figure out...