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December 7, 2007, 9:33 PM CT

James Webb Space Telescope Testing

James Webb Space Telescope Testing
A model of the James Webb Space Telescope's Mid-InfraRed Instrument will be tested before Christmas at the Rutherford Appleton Laboratory in Oxfordshire, England to ensure the final instrument can see infrared light.

Observing the universe in the infrared light portion of the spectrum is important because a number of objects researchers want to observe in space are far too cold to radiate at shorter wavelengths that can be seen as visible light, but they radiate strongly in infrared light.

The Mid-InfraRed Instrument (MIRI) is one of four sophisticated instruments onboard the Webb telescope which will study the early universe and properties of materials forming around new born stars in unprecedented detail. It will also be able to image directly massive planets orbiting other stars.

Speaking at the 3rd Appleton Space Conference on Dec. 6, European Consortium Lead for MIRI, Dr. Gillian Wright from the U.K. Astronomy Technology Centre (ATC) in Edinburgh said, "It is extremely exciting, after working on the project since 1998, to begin to test a complete instrument. This will provide researchers with real data which they can use to understand the best ways of making discoveries with the instrument".

MIRI's development is an effort between NASA and the European Space Agency (ESA). NASA's Jet Propulsion Laboratory in Pasadena (JPL), Calif, leads the NASA effort and is responsible for the development of MIRI's detectors, its cryocooler, and flight software.........

Posted by: Edwin      Read more         Source


November 27, 2007, 10:17 PM CT

Fatigue effects in silicon

Fatigue effects in silicon
Optical micrographs of contact damage in silicon from cyclic stress show progressive damage after (a) 1,000 cycles, (b) 5,000 cycles, (c) 20,000 cycles and (d) 85,000 cycles. Color added for clarity, white circle shows computed size of the contact circle.

Credit: NIST

Scientists at the National Institute of Standards and Technology (NIST) have demonstrated a mechanical fatigue process that eventually leads to cracks and breakdown in bulk silicon crystalsa phenomenon thats especially interesting because it long has been thought not to exist. Their recently published* results have important implications for the design of new silicon-based micro-electromechanical system (MEMS) devices that have been proposed for a wide variety of uses.

Siliconthe backbone of the semiconductor industryis one the worlds most heavily studied materials, and it has long been thought to beimmune to fatigue from cyclic stresses because of the nature of its crystal structure and chemical bonds. And indeed, conventional tests have validated this. Recent research into silicon MEMS devices, however, has revealed that these microscopic systems that incorporate tiny gears, vibrating reeds and other mechanical features do seem to develop stress-induced cracks that can lead to failure. Why this happens at the microscopic scale is a matter of debate. One school of thought holds that the effect is purely mechanical, due to friction, and the other argues that it essentially is caused by corrosiona chemical effect. Because the effect has only been noticed at submicrometer scales, it has been difficult to determine which theory is correct.........

Posted by: John      Read more         Source


Tue, 20 Nov 2007 01:48:28 GMT

Lupinus breweri var. breweri

Lupinus breweri var. breweri
Thank you again to one of the good folks at the University of Colorado at Boulder for today''s image and write-up. Janice Forbis is the assistant manager of the greenhouse in U of C''s Department of Ecology and Evolutionary Biology. A big thank you to you, Janice!

Janice writes:

“Lupinus breweri var. breweri is native to the western USA (Oregon, California and Nevada) and found in open montane forests at higher elevations of the alpine. It is a member of the Fabaceae or bean family, the third largest family in the number of species. Brewer''s lupine is a low-growing mat-forming plant, with silvery-silky leaves and densely hairy blue to violet petals. Alpine plants are strongly adapted to extreme conditions at high altitudes. The mat-forming or cushion habit is an advantage in wind resistance and avoiding damage from repetitive snowfalls. Hairy leaves are a way of limiting water loss in alpine areas which have free draining soils, frequent winds and high temperatures in the summer months.”

“This photo was taken during a week-end workshop, Flora of Mt. Ashland and the Eastern Siskiyous, part of The University of California at Berkeley Jepson Herbarium Weekend Workshop series.”

“It is always interesting to know where a plant name comes from. There are websites and exhibits, such as the one currently at the University of Colorado Museum titled “What''s in a Name? Understanding the World of Plants”. The name breweri is in honor of William Henry Brewer (1828-1910), an American botanist and professor. He was a botanical explorer of the California and Pacific Coast and his recommendations about Alaska led to its purchase by the United States in 1867 (source of plant name information: Michael Charters'' Plant Names).”

Posted by: Daniel Mosquin      Read more     Source


November 18, 2007, 8:56 PM CT

Local sources major cause of US near-ground aerosol pollution

Local sources major cause of US near-ground aerosol pollution
A new NASA study estimates that most ground-level particulate pollution in the United States stems from regional sources in North America and only a small amount is brought to the country from other parts of the world.

Scientists using an innovative global aerosol tracking model have for the first time produced a global estimate of sources and movements of aerosols near the ground where they can affect human health and run afoul of environmental regulations. Previously, scientists studying aerosols moving between continents focused primarily on tracking a single type of aerosol, such as dust or black carbon, or measuring their quantities throughout the atmosphere. This left gaps in understanding where ground-level particulate pollution comes from.

"This is the first study to comprehensively consider the origin, composition and type of fine particles over the United States and connect them to both domestic and foreign sources." said Mian Chin, an atmospheric scientist at NASAs Goddard Space Flight Center, Greenbelt, Md., and lead author of the study.

Aerosols are airborne particles that arise from both human sources such as burning fossil fuels, and natural sources such as fires, dust and volcanoes. They are also a major source of near-ground pollution. Since 1970, particulate matter has been regulated in the United State s by the Clean Air Act. A more recent concern has been aerosols that arrive here from distant shores carried by the wind.........

Posted by: Nora      Read more         Source


November 18, 2007, 8:45 PM CT

Seven-year-old becomes 'scientist for a day'

Seven-year-old becomes 'scientist for a day'
Seven-year-old Juliana Bach uses drops of dye and floating beads to study the pattern of water movement in a shallow basin.
When I grow up, I want to be a scientist. How a number of MIT students uttered these words when they were children? Though not an MIT student, Juliana Bach, a 7-year-old from Miami, discovered her passion for science at a young age. On Tuesday, Nov. 13, MIT, in conjunction with the Make-A-Wish Foundation, made her wish to be a scientist come true.

As Juliana works in the lab, she looks like a miniature scientist, wearing a white lab coat with her name stitched across the front. With her earnest demeanor and straight posture, Juliana exhibits all the characteristics of an eager science student. The only indications of her young age are the pink pants peeking out from below her lab coat, the high ponytail swinging on top of her head, and her tiny infectious giggle. What her physical appearance and positive demeanor cannot tell you, however, is that Juliana has leukemia.

Juliana's parents approached the Make-A-Wish Foundation about her desire to be to a scientist and were promptly directed to MIT, which was delighted to host her on campus. Juliana's requests while at MIT were to experiment with chemical reactions, discover how liquids change color, find out why there are different colors of sand, and make "goop."

Juliana first met with Heidi Nepf, director of the Environmental Fluid Mechanics Lab and professor of civil and environmental engineering. Nepf worked with Juliana to demonstrate aspects of how water moves in rivers, lakes and the coastal zone. The experiments were all based on prior or current research in Nepf's laboratory, but scaled down in size and concept to be understandable to a 7-year-old.........

Posted by: Nora      Read more         Source


November 18, 2007, 8:42 PM CT

'Noah's flood' kick-started European farming

'Noah's flood' kick-started European farming
Image courtesy of Noahs Ark Floor Puzzle
The flood thought to bebehind the Noahs Ark myth kick-started European agriculture, as per new research by the Universities of Exeter, UK and Wollongong, Australia. Reported in the journal Quaternary Science Reviews, the research paper assesses the impact of the collapse of the North American (Laurentide) Ice Sheet, 8000 years ago. The results indicate a catastrophic rise in global sea level led to the flooding of the Black Sea and drove dramatic social change across Europe. The research team argues that, in the face of rising sea levels driven by contemporary climate change, we can learn important lessons from the past.

The collapse of the Laurentide Ice Sheet released a deluge of water that increased global sea levels by up to 1.4 metres and caused the largest North Atlantic freshwater pulse of the last 100,000 years. Before this time, a ridge across the Bosporus Strait dammed the Mediterranean and kept the Black Sea as a freshwater lake. With the rise in sea level, the Bosporus Strait was breached, flooding the Black Sea. This event is now widely thought to bebehind the various folk myths that led to the biblical Noahs Ark story. Archaeological records show that around this time there was a sudden expansion of farming and pottery production across Europe, marking the end of the Mesolithic hunter-gatherer era and the start of the Neolithic. The link between rising sea levels and such massive social change has previously been unclear.........

Posted by: Nora      Read more         Source


November 14, 2007, 9:22 PM CT

effects of low dose arsenic on development

effects of low dose arsenic on development
Jennifer Davey and Joshua Hamilton (photo by Joseph Mehling '69)
A team of Dartmouth Medical School (DMS) scientists has determined that low doses of arsenic disrupt the activity of a hormone critical in development. The finding is further evidence that arsenic at low doses (at levels found in U.S. drinking water in some areas) can be harmful. The study appeared in the Oct. 26, 2007, online edition of the journal Environmental Health Perspectives (EHP), and it will be published in a forthcoming issue of the journal.

"Arsenic is a natural, yet pervasive, chemical in the environment; we can't seem to escape it," says Joshua Hamilton, one of the authors on this study and the director of the Center for Environmental Health Sciences at Dartmouth and Dartmouth's Superfund Basic Research Program on Toxic Metals. "By learning how it adversely affects biological processes and at what levels we should be concerned, we will hopefully someday be able to mitigate its impact on human health." Hamilton is also a professor of pharmacology and toxicology at DMS.

Hamilton and his team, in prior work, have learned that arsenic at low doses appears to suppress the ability of all critical steroid receptors, including those for estrogen and testosterone, to respond to their normal hormone signals. Chemicals that disrupt steroid hormone receptor signaling are called endocrine disruptors. Arsenic can disrupt these hormone pathways at extremely low doses equivalent to what a number of people in the U.S. have in their drinking water.........

Posted by: Nora      Read more         Source


October 24, 2007, 7:27 PM CT

NASA Views Southern California Fires and Winds

NASA Views Southern California Fires and Winds
With a click of the mouse button, the public can see NASA views from space, including some at Google Earth, of Southern California's raging wildfires and the ferocious Santa Ana winds that are driving them.

Images taken by the Moderate Resolution Imaging Spectroradiometer (Modis) on NASA's Terra and Aqua satellites are processed daily and made available by the JPL OnEarth Web Map Server, and at Google Earth. This effort is part of an ongoing collaboration with JPL, Google Earth, and NASA Ames Research Center, Moffett Field, Calif., to make remote satellite imagery available to the public and decision makers. Latest Modis fire images at onearth.jpl.nasa.gov/socalfires.........

Posted by: Edwin      Read more         Source


October 23, 2007, 10:04 PM CT

Fifty Times sharper than Hubble

Fifty Times sharper than Hubble
The Inner Jet of the Radio Galaxy M87 located in the Virgo cluster. The angular resolution of this false-color radio image observed by the VLBA at 2 cm wavelength is approximately one milli-arcsecond, fifty times better than that of the Hubble Space Telescope at optical wavelengths. The image shows a limb brightened jet and a faint counter-jet. The central gap is consistent with the presence of a fast inner jet which is beamed away from the observer surrounded by a slower moving outer plasma seen by the VLBA.
Image: Y.Y. Kovalev, MPIfR Bonn
M87, the central galaxy of the Virgo cluster in a distance of only 50 million light years, was observed by Yuri Kovalev from the Max Planck Institute for Radio Astronony (MPIfR) in Bonn and colleagues with the VLBA (Very Long Baseline Array) at 2 cm wavelength. The resulting image provides details down to a resolution of one milli-arcsecond, corresponding to a linear resolution of only three light months. The new image of the inner radio jet of M87 shows a highly collimated jet which appears limb-brightened, and also a faint counter-jet. It is unprecedented in its combination of sensitivity and spatial resolution.

The observations were performed with the Very Long Baseline Array (VLBA) of the National Radio Astronomy Observatory (NRAO), consisting of ten radio antennas in North America including Hawaii and Virgin Island and an additional telescope from the Very Large Array (VLA) near Socorro, New Mexico. The Effelsberg 100m radio telescope is regularly used for transatlantic baselines extending the VLBA observations. "With the 100m radio telescope, we plan to increase the spatial resolution and provide an even more detailed image of the M87 jet", says Yuri Kovalev.........

Posted by: Edwin      Read more         Source


September 17, 2007, 10:37 PM CT

Volatile Organic Compounds In Water And Air

Volatile Organic Compounds In Water And Air
Boris Mizaikoff, an associate professor in Georgia Tech's School of Chemistry and Biochemistry, and graduate student Yuliya Luzinova inspect a microsensor chip coated with polymer layers under a microscope.

Credit: Gary Meek

Scientists at the Georgia Institute of Technology have developed a miniature sensor that uses polymer membranes deposited on a tiny silicon disk to measure pollutants present in aqueous or gaseous environments. An array of these sensors with different surface coatings could be used during field-testing to rapidly detect a number of different chemicals.

Since this new sensor allows water and air samples to be analyzed in the field, it is an improvement over classical techniques that require samples be carried back to the laboratory for analysis. This research, funded by the National Science Foundation, was presented on August 20 at the American Chemical Societys 234th National Meeting.

The heart of the disk-shaped sensor is a microbalance that measures the mass of pollutant molecules.

When pollutant chemicals get adsorbed to the surface of the sensor, a frequency change of the vibrating microbalance provides a measure of the associated mass change, said Oliver Brand, associate professor in Georgia Techs School of Electrical and Computer Engineering.

Cantilever-type balances, which move up and down like a diving board, are common when measuring the amount of a chemical in the gas phase. However, the mechanical vibrations of the balance used to detect the mass changes are damped in liquids, causing the sensitivity of the balance to decrease. Thus, Brand and graduate students Jae Hyeong Seo, Stuart Truax and Kemal Safak Demirci searched for structures whose vibrations were less affected by the surrounding medium.........

Posted by: Nora      Read more         Source


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