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Thu, 03 Jul 2008 23:04:27 GMT

Drosanthemum bicolor

Drosanthemum bicolor
Nhu Nguyen, aka xerantheum@Flickr is the photographer behind today''s image (original via BPotD Flickr Group Pool).Thank you!

The common name for Drosanthemum is dew-flower, which also happens to a literal translation of the name of the genus (drosos meaning dew and anthos meaning flower). This is in reference to the glistening papillae found on branches and flowering stems -- you can see this phenomenon in today''s photograph with a close look at the topmost unopened flower bud.

Although native to South Africa, one species of Drosanthemum (not D. bicolor) has naturalized in California, so the Flora of North America has an entry on the genus: Drosanthemum.

Posted by: Daniel Mosquin      Read more     Source


Thu, 03 Jul 2008 15:46:57 GMT

Yucca brevifolia

Yucca brevifolia
By special request (from a conversation with a friend on the weekend), here''s an infrared photograph of Yucca brevifolia (along with a non-IR photograph of the inflorescence).

Joshua trees have made a previous appearance on BPotD in a brief entry on Joshua Tree National Park. In the comments section, Bill Hooker of Open Reading Frame suggested this article by Chris Clarke on Creek Running North: Joshua trees and extinction. In a bit of coincidence, during the same month that Chris wrote his piece, a journal article came out that suggested things are a bit more hopeful for the Joshua tree than was thought at the time. See: Vander Wall et al. 2006. Joshua tree (Yucca brevifolia) seeds are dispersed by seed-caching rodents. Ecoscience. 13(4): 539-543.

Since it''s a well-known plant from California (and also Arizona, Utah, Nevada and Baja California), excellent resources for more information exist: Calphotos, the Fire Effects Information System factsheet, and the Flora of North America: Yucca brevifolia.

Posted by: Daniel Mosquin      Read more     Source


July 1, 2008, 9:59 PM CT

New DNA weapon against avian flu

New DNA weapon against avian flu
Scientists at the University of Pennsylvania School of Medicine have identified a potential new way to vaccinate against avian flu. By delivering vaccine via DNA constructed to build antigens against flu, along with a minute electric pulse, scientists have immunized experimental animals against various strains of the virus. This approach could allow for the build up of vaccine reserves that could be easily and effectively dispensed in case of an epidemic. This study was published last week in PLoS ONE

"This is the first study to show that a single DNA vaccine can induce protection against strains of pandemic flu in a number of animal models, including primates," says David B. Weiner, Ph.D., Professor of Pathology and Laboratory Medicine. "With this type of vaccine, we can generate a single construct of a pandemic flu vaccine that will give much broader protection".

Traditional vaccines expose a formulation of a specific strain of flu to the body so it can create immune responses against that specific strain. On the other hand, a DNA vaccine becomes part of the cell, giving it the blueprint it needs to build antigens that can induce responses that target diverse strains of pandemic flu.

Avian flu is tricky. Not only is it deadly, but it mutates quickly, generating different strains that escape an immune response targeted against one single strain. Preparing effective vaccines for pandemic flu in advance with either live or killed viruses, which protect against only one or few cross-strains, is therefore very difficult. How to predict which strain of avian flu may appear at any time is difficult. "We are always behind in creating a vaccine that can effectively protect against that specific strain," notes Weiner.........

Posted by: Nora      Read more         Source


June 26, 2008, 8:35 PM CT

Porous Nanostructures For Better Fuel Cells

Porous Nanostructures For Better Fuel Cells
Computer simulation, left, shows how platinum nanoparticles will fuse into a structure with tiny pores after the polymers that guide them into position are removed. Right, electron microscope photo of the actual structure.
For 5,000 years or so, the only way to shape metal has been to "heat and beat." Even in modern nanotechnology, working with metals involves carving with electron beams or etching with acid.

Now, Cornell scientists have developed a method to self-assemble metals into complex nanostructures. Applications include making more efficient and cheaper catalysts for fuel cells and industrial processes and creating microstructured surfaces to make new types of conductors that would carry more information across microchips than conventional wires do.

The method involves coating metal nanoparticles -- about 2 nanometers (nm) in diameter -- with an organic material known as a ligand that allows the particles to be dissolved in a liquid, then mixed with a block co-polymer (a material made up of two different chemicals whose molecules link together to solidify in a predictable pattern). When the polymer and ligand are removed, the metal particles fuse into a solid metal structure.

"The polymer community has tried to do this for 20 years," said Ulrich Wiesner, Cornell professor of materials science and engineering, who, with colleagues, reports on the new method in the June 27 issue of the journal Science. "But metals have a tendency to cluster into uncontrolled structures. The new thing we have added is the ligand, which creates high solubility in an organic solvent and allows the particles to flow even at high density".........

Posted by: John      Read more         Source


June 26, 2008, 8:29 PM CT

Standards Set for Energy-Conserving LED Lighting

Standards Set for Energy-Conserving LED Lighting
These solid-state lights are powered by energy-efficient light emitting diodes and are among the first ones of a new generation expected to cut energy needed for lighting by 50 percent by 2027.
Researchers at the National Institute of Standards and Technology (NIST), in cooperation with national standards organizations, have taken the lead in developing the first two standards for solid-state lighting in the United States. This new generation lighting technology uses light-emitting diodes (LEDs) instead of incandescent filaments or fluorescent tubes to produce illumination that cuts energy consumption significantly.

Standards are important to ensure that products will have high quality and their performance will be specified uniformly for commerce and trade. These standards-the most recent of which published last month-detail the color specifications of LED lamps and LED light fixtures, and the test methods that manufacturers should use when testing these solid-state lighting products for total light output, energy consumption and chromaticity, or color quality.

Solid-state lighting is expected to significantly reduce the amount of energy needed for general lighting, including residential, commercial and street lighting. "Lighting," explains NIST scientist Yoshi Ohno, "uses 22 percent of the electricity and 8 percent of the total energy spent in the country, so the energy savings in lighting will have a huge impact".

Solid-state lighting is expected to be twice as energy efficient as fluorescent lamps and 10 times more efficient than incandescent lamps, eventhough the current products are still at their early stages. Ohno chaired the task groups that developed these new standards.........

Posted by: John      Read more         Source


June 23, 2008, 7:00 PM CT

Discovery could enable development of faster computers

Discovery could enable development of faster computers
Sketch of a ferromagnet/semiconductor structure. When the MgO interface is very thin, spin up electrons, represented in this image with an arrow to the right, are reflected back to the semiconductor. At an intermediate thickness of the interface, spin down electrons are reflected back to the semiconductor, resulting in a "spin reversal" that can be used to control current flow.

Credit: Kawakami lab, UC Riverside
Physicists at UC Riverside have made an accidental discovery in the lab that has potential to change how information in computers can be transported or stored. Dependent on the "spin" of electrons, a property electrons possess that makes them behave like tiny magnets, the discovery could help in the development of spin-based semiconductor technology such as ultrahigh-speed computers.

The researchers were experimenting with ferromagnet/semiconductor (FM/SC) structures, which are key building blocks for semiconductor spintronic devices (microelectronic devices that perform logic operations using the spin of electrons). The FM/SC structure is sandwich-like in appearance, with the ferromagnet and semiconductor serving as microscopically thin slices between which lies a thinner still insulator made of a few atomic layers of magnesium oxide (MgO).

The researchers found that by simply altering the thickness of the MgO interface they were able to control which kinds of electrons, identified by spin, traveled from the semiconductor, through the interface, to the ferromagnet.

Study results appear in the June 13 issue of Physical Review Letters

Experimental results:

The spin of an electron is represented by a vector, pointing up for an Earth-like west-to-east spin; and down for an east-to-west spin.........

Posted by: John      Read more         Source


June 19, 2008, 9:15 PM CT

Tiny refrigerator taking shape to cool future computers

Tiny refrigerator taking shape to cool future computers
Miniature refrigeration system
Researchers at Purdue University are developing a miniature refrigeration system small enough to fit inside laptops and personal computers, a cooling technology that would boost performance while shrinking the size of computers.

Unlike conventional cooling systems, which use a fan to circulate air through finned devices called heat sinks attached to computer chips, miniature refrigeration would dramatically increase how much heat could be removed, said Suresh Garimella, the R. Eugene and Susie E. Goodson Professor of Mechanical Engineering.

The Purdue research focuses on learning how to design miniature components called compressors and evaporators, which are critical for refrigeration systems. The researchers developed an analytical model for designing tiny compressors that pump refrigerants using penny-size diaphragms and validated the model with experimental data. The elastic membranes are made of ultra-thin sheets of a plastic called polyimide and coated with an electrically conducting metallic layer. The metal layer allows the diaphragm to be moved back and forth to produce a pumping action using electrical charges, or "electrostatic diaphragm compression".

In related research, the engineers are among the first to precisely measure how a refrigerant boils and vaporizes inside tiny "microchannels" in an evaporator and determine how to vary this boiling rate for maximum chip cooling.........

Posted by: John      Read more         Source


April 28, 2008, 5:27 PM CT

'Sticky nanotubes' hold key to future technologies

'Sticky nanotubes' hold key to future technologies
Nanotube attached to a "microcantilever"
Scientists at Purdue University are the first to precisely measure the forces mandatory to peel tiny nanotubes off of other materials, opening up the possibility of creating standards for nano-manufacturing and harnessing a gecko's ability to walk up walls.

So-called "peel tests" are used extensively in manufacturing. Knowing how much force is needed to pull a material off of another material is essential for manufacturing, but no tests exist for nanoscale structures, said Arvind Raman, an associate professor of mechanical engineering at Purdue.

Scientists are trying to learn about the physics behind the "stiction," or how the tiny structures stick to other materials, to manufacture everything from nanoelectronics to composite materials, "nanotweezers" to medical devices using nanotubes, nanowires and biopolymers such as DNA and proteins, he said.

Flexible carbon nanotubes stick to surfaces differently than larger structures because of attractive forces between individual atoms called van der Waals forces.

"Operating in a nanoscale environment is sort of like having flypaper everywhere because of the attraction of van der Waals forces," Raman said. "These forces are very relevant on this size scale because a nanometer is about 10 atoms wide".........

Posted by: John      Read more         Source


April 10, 2008, 8:06 PM CT

Waterman Award to UCLA's 'Mozart of Math'

Waterman Award to UCLA's 'Mozart of Math'
The National Science Foundation (NSF) is proud to announce that 32-year-old Terence Tao, a professor of mathematics at the University of California at Los Angeles, will receive its 2008 Alan T. Waterman Award. Called a "supreme problem-solver," and named one of "the Brilliant 10" researchers by Popular Science (October 2006), Tao's extraordinary work, much of which has been funded by NSF through the years, has had a tremendous impact across several mathematical areas. He will receive the award at a black tie dinner program at the U.S. Department of State on May 6.

The annual Waterman award recognizes an outstanding young researcher in any field of science or engineering supported by NSF. Candidates may not be more than 35 years old, or seven years beyond receiving a doctorate, and must stand out for their individual achievements. In addition to a medal, the awardee receives a grant of $500,000 over a 3-year period for scientific research or advanced study in their field.

Terence Tao was born in Adelaide, Australia, in 1975. His genius at mathematics began early in life. He started to learn calculus when he was 7 years old, at which age he began high school; by the age of 9 he was already very good at university-level calculus. By the age of 11, he was thriving in international mathematics competitions. Tao was 20 when he earned his doctorate from Princeton University, and he joined UCLA's faculty that year. UCLA promoted him to full professor at age 24. Tao now holds UCLA's James and Carol Collins Chair in the College of Letters and Science. He is also a fellow of the Royal Society and the Australian Academy of Sciences (corresponding member).........

Posted by: John      Read more         Source


March 18, 2008, 4:54 AM CT

Fake Diamonds Help Jet Engines Take The Heat

Fake Diamonds Help Jet Engines Take The Heat
Ohio State University engineers are in the process of developing a technology to coat jet engine turbine blades with zirconium dioxide -- usually called zirconia, the stuff of synthetic diamonds -- to combat high-temperature corrosion.

The zirconia chemically converts sand and other corrosive particles that build up on the blade into a new, protective outer coating. In effect, the surface of the engine blade constantly renews itself.

Ultimately, the technology could enable manufacturers to use new kinds of heat-resistant materials in engine blades, so that engines will be able to run hotter and more efficiently.

Nitin Padture, professor of materials science and engineering at Ohio State, said that he had military aircraft in mind when he began the project. He was then a professor at the University of Connecticut.

"In the desert, sand is sucked into the engines during takeoffs and landings, and then you have dust storms," he said. "But even commercial aircraft and power turbines encounter small bits of sand or other particles, and those particles damage turbine blades".

Jet engines operate at thousands of degrees Fahrenheit, and blades in the most advanced engines are coated with a thin layer of temperature-resistant, thermally-insulating ceramic to protect the metal blades. The coating -- referred to as a thermal-barrier coating -- is designed like an accordion to expand and contract with the metal.........

Posted by: John      Read more         Source


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