Fact of the day!
Today’s science fact is about the Texan Horned Lizard.
This lizard deters predators by shooting its own blood into their face. Out of its eyes. Apparently the blood taste......Learn More!
The NASA Mars rover Curiosity this week is driving within a shallow depression called "Yellowknife Bay," providing information to help researchers choose a rock to drill.
The NASA Mars rover Curiosity used its left Navigation Camera to record this view of the step down into a shallow depression called "Yellowknife Bay." (Credit: NASA/JPL-Caltech)
Yellowknife Bay is within a different type of terrain from what the rover has traversed since landing inside Mars' Gale Crater on Aug. 5, PDT (Aug. 6, UTC). The terrain Curiosity has entered is one of three types that intersect at a location dubbed "Glenelg," chosen as an interim destination about two weeks after the landing.Using Curiosity's percussive drill to collect a sample from the interior of a rock, a feat never before attempted on Mars, is the mission's priority for early 2013. After the powdered-rock sample is sieved and portioned by a sample-processing mechanism on the rover's arm, it will be analyzed by instruments inside Curiosity.
Curiosity reached the lip of a 2-foot (half-meter) descent into Yellowknife Bay with a 46-foot (14-meter) drive on Dec. 11. The next day, a drive of about 86 feet (26.1 meters) brought the rover well inside the basin. The team has been employing the Mast Camera (Mastcam) and the laser-wielding Chemistry and Camera (ChemCam) for remote-sensing studies of rocks along the way.
On Dec. 14, Curiosity drove about 108 feet (32.8 meters) to reach rock targets of interest called "Costello" and "Flaherty." Researchers used the Alpha Particle X-Ray Spectrometer (APXS) and Mars Hand Lens Imager (MAHLI) at the end of the rover's arm to examine the targets. After finishing those studies, the rover drove again on Dec. 17, traveling about 18 feet (5.6 meters) farther into Yellowknife Bay. That brings the mission's total driving distance to 0.42 mile (677 meters) since Curiosity's landing.
One additional drive is planned this week before the rover team gets a holiday break. Curiosity will continue studying the Martian environment from its holiday location at the end point of that drive within Yellowknife Bay. The mission's plans for most of 2013 center on driving toward the primary science destination, a 3-mile-high (5-kilometer) layered mound called Mount Sharp.
NASA's Mars Science Laboratory Project is using Curiosity during a two-year prime mission to assess whether areas inside Gale Crater ever offered a habitable environment for microbes. NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the project for NASA's Science Mission Directorate in Washington.
More information about Curiosity is online athttp://www.jpl.nasa.gov/msl , http://www.nasa.gov/msl andhttp://mars.jpl.nasa.gov/msl/ . You can follow the mission on Facebook at: http://www.facebook.com/marscuriosity and on Twitter at: http://www.twitter.com/marscuriosity .
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NASA completed the latest in a series of parachute tests for its Orion spacecraft Thursday at the U.S. Army Yuma Proving Ground in southwestern Arizona, marking another step toward a first flight test in 2014. The test verified Orion can land safely even if one of its two drogue parachutes does not open during descent.
A mockup Orion capsule is poised to drop from a plane 25,000 feet above the U.S. Army Yuma Proving Ground in Arizona to test the parachute design for the spacecraft that will take humans farther than they’ve ever been before – and return them to Earth at greater speeds than ever before. (Credit: NASA)
Orion will take humans farther into space than ever before, but one of the most challenging things the multipurpose vehicle will do is bring its crew home safely. Because it will return from greater distances, Orion will reenter Earth's atmosphere at speeds of more than 20,000 mph. After re-entry, the parachutes are all that will lower the capsule carrying astronauts back to Earth.
"The mockup vehicle landed safely in the desert and everything went as planned," said Chris Johnson, a NASA project manager for Orion's parachute assembly system. "We designed the parachute system so nothing will go wrong, but plan and test as though something will so we can make sure Orion is the safest vehicle ever to take humans to space."Orion will take humans farther into space than ever before, but one of the most challenging things the multipurpose vehicle will do is bring its crew home safely. Because it will return from greater distances, Orion will reenter Earth's atmosphere at speeds of more than 20,000 mph. After re-entry, the parachutes are all that will lower the capsule carrying astronauts back to Earth.
Orion uses five parachutes. Three are main parachutes measuring 116 feet wide and two are drogue parachutes measuring 23 feet wide. The 21,000-pound capsule needs only two main parachutes and one drogue. The extra two provide a backup in case one of the primary parachutes fails.
To verify Orion could land safely with only one drogue parachute, engineers dropped a spacecraft mockup from a plane 25,000 feet above the Arizona desert and simulated a failure of one of the drogues. About 30 seconds into the mockup's fall, the second drogue parachute opened and slowed the mockup down enough for the three main parachutes to take over the descent.
The next Orion parachute test is scheduled for February and will simulate a failure of one of the three main parachutes.
In 2014, an uncrewed Orion spacecraft will launch from Cape Canaveral Air Force Station in Florida on Exploration Flight Test-1. The spacecraft will travel 3,600 miles above Earth's surface. This is 15 times farther than the International Space Station's orbit and farther than any spacecraft designed to carry humans has gone in more than 40 years. The main flight objective is to test Orion's heat shield performance at speeds generated during a return from deep space.
For information about Orion, visit: http://www.nasa.gov/orion
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University of Toronto Faculty of Medicine researchers have uncovered a genetic basis for fundamental differences between humans and other vertebrates that could also help explain why humans are susceptible to diseases not found in other species.
Wild Chimpanzee. (Credit: © UryadnikovS / Foto
The team sequenced and compared the composition of hundreds of thousands of genetic messages in equivalent organs, such as brain, heart and liver, from 10 different vertebrate species, ranging from human to frog. They found that alternative splicing -- a process by which a single gene can give rise to multiple proteins -- has dramatically changed the structure and complexity of genetic messages during vertebrate evolution.Scientists have wondered why vertebrate species, which look and behave very differently from one another, nevertheless share very similar repertoires of genes. For example, despite obvious physical differences, humans and chimpanzees share a nearly identical set of genes.
The results suggest that differences in the ways genetic messages are spliced have played a major role in the evolution of fundamental characteristics of species. However, the same process that makes species look different from one another could also account for differences in their disease susceptibility.
"The same genetic mechanisms responsible for a species' identity could help scientists understand why humans are prone to certain diseases such as Alzheimer's and particular types of cancer that are not found in other species," says Nuno Barbosa-Morais, the study's lead author and a computational biologist in U of T Faculty of Medicine's Donnelly Centre for Cellular and Biomolecular Research. "Our research may lead to the design of improved approaches to study and treat human diseases."
One of the team's major findings is that the alternative splicing process is more complex in humans and other primates compared to species such as mouse, chicken and frog.
"Our observations provide new insight into the genetic basis of complexity of organs such as the human brain," says Benjamin Blencowe, Professor in U of T's Banting and Best Department of Research and the Department of Molecular Genetics, and the study's senior author.
"The fact that alternative splicing is very different even between closely related vertebrate species could ultimately help explain how we are unique."
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Baylor University researchers are one step closer to understanding the algae that causes a substantial number of fish deaths in more than 18 states.
The study was published in the December issue of Harmful Algae.Golden algae, Texas Tide orPrymnesium parvum, as it is known by its scientific name, produces toxins that can severely impact aquatic organisms. Over the past decade, golden algae blooms have been responsible for the death of tens of millions of fish in Texas reservoirs.
Bryan W. Brooks, Ph.D., professor of environmental science and biomedical studies at Baylor and director of the environmental science graduate program and the environmental health science program, and his research team found that neutral pH levels prevented the algae's bloom development and the toxicity of the algae was greatly diminished.
"Our novel findings identify that surface water pH is a very important factor influencing whether harmful algal blooms of Prymnesium parvum will even occur in a lake or reservoir," Brooks said. "In addition to better understanding the ecology and toxicology of this invasive species, this new information promises to support more sustainable environmental management of fisheries and drinking water supplies."
Brooks and his research team conducted two experiments -- one during pre-bloom period and another during bloom development -- over 21 days to gauge the effect of pH 7 and 7.5 on toxicity of golden algae. The study -- in Lake Granbury, Texas, a common site of destructive golden algae blooms -- also included untreated lake water with pH of 8.5.
"In the bloom development experiment, acute toxicity to fish was observed in the untreated lake water (pH 8.5) and in the pH 7.5 treatment level as early as Day 7. However, the pH 7 treatment levels remained free from acute toxicity throughout the 21-day study," said Krista N. Prosser, Baylor environmental science graduate student and lead author of the study.
Researchers can now better identify when and where harmful blooms may occur and develop solutions to minimize the impact of golden algae.
"Because golden algae blooms appears to originate in coves that experience lower inflows than the main reservoir stems, coves may represent more reasonable management units to create refuge habitats and potentially preempt bloom formation," Brooks said.
Golden algae can be found in the following states: Ala., Ariz., Ark., Calif., Fla., Hawaii, La., Maine, Miss., N.C., N.M., Okla., Pa., S.C., Texas, Wash., W.Va. and Wyo.
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Dec. 23, 2012 — Peatlands (bogs, turf moors) are among the most important ecosystems worldwide for the storage of atmospheric carbon and thus for containing the climate warming process. In the last 30 to 50 years the peat (Sphagnum) mosses, whose decay produces the peat (turf), have come under pressure by vascular plants, mostly small shrubs.
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| A set of biogeochemical feedbacks between soil microbes and vascular plants can explain the expansion of small shrubs in peatlands in response to climate warming. (Credit: Luca Bregazza / WSL) |
The findings in a nutshell
A new study by scientists from the Swiss Federal Institute for Forest, Snow and Landscape Research WSL and from the Ecole Polytechnique Fédérale de Lausanne (Switzerland) describes for the first time what lies behind this change in vegetation and explains why vascular plants are at an advantage over peat (Sphagnum ) mosses in a warmer climate.
The research team closely monitored four peatland sites at altitudes ranging from 600 m to 1900 m over a period of three years. The selected altitudinal gradient reflects the expected changes in climate conditions for the year 2050[1] in northern Switzerland. They observed that the increase of shrub cover and soil temperature along the altitudinal gradient were responsible for a decrease of almost 50% of the production of new litter by peat mosses, the main contributors to peat accumulation.
The analysis showed that vascular plants can increase the availability of soil nitrogen (a primary nutrient for plant growth) by means of specific compounds contained in their leaves. They exploit the nutrient for their growth through the mediation of specific fungal symbiosis at root level (the mycorrhiza), a process that becomes more and more frequent when soil temperature increases. At the same time, with higher soil temperature vascular plants release a greater amount of organic matter into the soil through their roots (the so called "root exudates") and this stimulates the decomposition activity of soil microbes.
As fewer peat mosses grow, there will be less new peat to store atmospheric carbon. In addition, the increased decomposition activity of soil microbes accelerates the decomposition of old peat. Thus, carbon that might otherwise be kept in storage for millennia can be released into the atmosphere. This situation casts a black shadow on the capacity of peatlands to continue to accumulate atmospheric carbon. As a consequence, peatlands can turn from carbon sinks to carbon sources, thus intensifying the climate warming instead of contributing to reducing it.
Peatlands play a central role in climate protection
Although peatlands are estimated to cover only 3% of the world land surface, they store about 30% of all soil organic matter, an amount equivalent to about 50% of the atmospheric CO2. On global scale, peatlands stock an amount of carbon which is twice the carbon stock of all forest biomass. In this sense, peatlands can be considered as "hot spots" of carbon accumulation and they have contributed, over millennia, to cool the climate by retrieving greenhouse gases from the atmosphere.
In Switzerland, peatlands have become known to the general public because of the Rothenturm initiative, which was followed by an article in the Swiss Constitution in 1987 to save peatlands from destruction.
In peatlands, the accumulation of peat is primarily promoted by a peculiar group of plants called "peat mosses" (technically, Sphagnum mosses), whose litter has antibiotic properties that hamper the decomposing activity of soil microbes. In addition, the presence of abundant water in peatland soil not only promotes the growth of peat mosses (which do not have roots, like vascular plants), but also creates anoxic conditions that further reduce the decomposition of plant litter. In a typical peatland, peat mosses dominate the landscape.
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Story Source:
The above story is reprinted from materials provided bySwiss Federal Institute for Forest, Snow and Landscape Research WSL.Note: Materials may be edited for content and length. For further information, please contact the source cited above.
Journal Reference:
- Luca Bragazza, Julien Parisod, Alexandre Buttler, Richard D. Bardgett. Biogeochemical plant–soil microbe feedback in response to climate warming in peatlands. Nature Climate Change, 2012; DOI:10.1038/nclimate1781
Dec. 21, 2012 — Galactan is a polymer of galactose, a six-carbon sugar that can be readily fermented by yeast into ethanol and is a target of interest for researchers in advanced biofuels produced from cellulosic biomass. Now an international collaboration led by scientists at the U.S. Department of Energy (DOE)'s Joint BioEnergy Institute (JBEI) has identified the first enzyme capable of substantially boosting the amount of galactan in plant cell walls.
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| JBEI researchers Henrik Scheller and April Liwanag led a study in which the first enzyme capable of increasing the biosynthesis of galactan was identified. (Credit: Image courtesy of DOE/Lawrence Berkeley National Laboratory) |
"We have confirmed the identity of the GT92 enzyme as the first enzyme shown to increase the biosynthesis of galactan," says Henrik Scheller, vice president for JBEI's Feedstocks Division and director of its Cell Wall Biosynthesis group. "This identification of the first β-1,4-galactan synthase provides an important new tool for the engineering of advanced bioenergy fuel crops."Unlike ethanol, advanced biofuels synthesized from the sugars in plant cells walls could replace gasoline, diesel and jet fuels on a gallon-for-gallon basis and be dropped into today's engines and infrastructures with no modifications required. Also, adanced biofuels have the potential to be carbon-neutral, meaning they could be burned without adding excess carbon to the atmosphere. Among the key challenges to making advanced biofuels cost competitive is finding ways to maximize the amount of plant cell wall sugars that can be fermented into fuels.
Scheller, who also holds an appointment with DOE's Lawrence Berkeley National Laboratory (Berkeley Lab), is the corresponding author of a paper in the journal Plant Cell that describes this work. The paper is titled "Pectin Biosynthesis: GALS1 in Arabidopsis thaliana is a β-1,4-Galactan β-1,4-galactosyltransferase." Co-authors were JBEI's April Liwanag, Berit Ebert, Yves Verhertbruggen, Emilie Rennie, Carsten Rautengarten, and Ai Oikawa, plus Mathias Andersen and Mads Clausen of the Technical University of Denmark.
Galactans are polysaccharide components of pectin, the sticky sugar substance that binds together the individual cells in plant cell walls and is used to make jellies and jams. The β-1,4-galactan component of pectin is especially abundant in the "tension wood" that forms in cell walls in response to mechanical stress from wind or snowfall.
"Galactans are composed of hexoses, which in contrast to pentoses, are easily utilized by fermenting microorganisms for the production of biofuels and other compounds," Scheller says. "It would be advantageous to develop plants with increased galactan content instead of hemicelluloses consisting largely of pentoses."
GT92 is a family of glycosyltransferase proteins whose genes are found in all plants that have been genetically sequenced. An increased expression of GT92 genes has been observed in studies of tension wood. This observation combined with the knowledge that tension wood is rich in β-1,4-galactan led Scheller and his colleagues to investigate the function of GT92 proteins in Arabidopsis thaliana, a small flowering relative of mustard that serves as a model organism for plant studies.Arabidopsis has three members of GT92, which Scheller and his colleagues designated as GALACTAN SYNTHASE 1,2 and 3 (GALS1, GALS2 and GALS3). While loss-of-function mutants in all three genes were found to be galactan deficient, Scheller and his colleague isolated and tested GALS1.
"Overexpression of GALS1 resulted in plants with 50-percent higher β-1,4-galactan content and no adverse phenotype," Scheller says. "We expect that the results for GALS2 and GALS3 overexpressors will be similar though we have yet to test them."
Given that all three Arabidopsis GALS genes showed overlapping but not identical expression, Scheller and his colleagues are now combining mutations of GALS genes to better understand the role of β-1,4-galactan in plants. They're also carrying out basic studies on these enzymes, including crystallization and structural analysis. In addition, they're overexpressing the GALS proteins in different combinations to determine if even higher production of β-1,4-galactan results.
"As β-1,4-galactan is an ancient invention, the function of GT92 as a galactan synthase in Arabidopsis should also be applicable to switchgrass, Miscanthus, poplar and other plants being considered as crops for advanced biofuels," Scheller says. "We do not anticipate any difficulty in being able to overexpress GT92 genes in these plants."
This research was funded by the DOE Office of Science, and by the Danish Strategic Research Council.
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Dec. 19, 2012 — A carbon-nanotube-coated lens that converts light to sound can focus high-pressure sound waves to finer points than ever before. The University of Michigan engineering researchers who developed the new therapeutic ultrasound approach say it could lead to an invisible knife for noninvasive surgery.
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| With a new technique that uses tightly-focused sound waves for micro-surgery, University of Michigan engineering researchers drilled a 150-micrometer hole in a confetti-sized artificial kidney stone. (Credit: Hyoung Won Baac) |
The beams that today's technology produces can be unwieldy, says Hyoung Won Baac, a research fellow at Harvard Medical School who worked on this project as a doctoral student in Guo's lab.Today's ultrasound technology enables far more than glimpses into the womb. Doctors routinely use focused sound waves to blast apart kidney stones and prostate tumors, for example. The tools work primarily by focusing sound waves tightly enough to generate heat, says Jay Guo, a professor of electrical engineering and computer science, mechanical engineering, and macromolecular science and engineering. Guo is a co-author of a paper on the new technique published in the current issue of Nature's journal Scientific Reports.
"A major drawback of current strongly focused ultrasound technology is a bulky focal spot, which is on the order of several millimeters," Baac said. "A few centimeters is typical. Therefore, it can be difficult to treat tissue objects in a high-precision manner, for targeting delicate vasculature, thin tissue layer and cellular texture. We can enhance the focal accuracy 100-fold."
The team was able to concentrate high-amplitude sound waves to a speck just 75 by 400 micrometers (a micrometer is one-thousandth of a millimeter). Their beam can blast and cut with pressure, rather than heat. Guo speculates that it might be able to operate painlessly because its beam is so finely focused it could avoid nerve fibers. The device hasn't been tested in animals or humans yet, though.
"We believe this could be used as an invisible knife for noninvasive surgery," Guo said. "Nothing pokes into your body, just the ultrasound beam. And it is so tightly focused, you can disrupt individual cells."
To achieve this superfine beam, Guo's team took an optoacoustic approach that converts light from a pulsed laser to high-amplitude sound waves through a specially designed lens. The general technique has been around since Thomas Edison's time. It has advanced over the centuries, but for medical applications today, the process doesn't normally generate a sound signal strong enough to be useful.
The U-M researchers' system is unique because it performs three functions: it converts the light to sound, focuses it to a tiny spot and amplifies the sound waves. To achieve the amplification, the researchers coated their lens with a layer of carbon nanotubes and a layer of a rubbery material called polydimethylsiloxane. The carbon nanotube layer absorbs the light and generates heat from it. Then the rubbery layer, which expands when exposed to heat, drastically boosts the signal by the rapid thermal expansion.
The resulting sound waves are 10,000 times higher frequency than humans can hear. They work in tissues by creating shockwaves and microbubbles that exert pressure toward the target, which Guo envisions could be tiny cancerous tumors, artery-clogging plaques or single cells to deliver drugs. The technique might also have applications in cosmetic surgery.
In experiments, the researchers demonstrated micro ultrasonic surgery, accurately detaching a single ovarian cancer cell and blasting a hole less than 150 micrometers in an artificial kidney stone in less than a minute.
"This is just the beginning," Guo said. "This work opens a way to probe cells or tissues in much smaller scale."
The researchers will present the work at the SPIE Photonics West meeting in San Francisco. The research was funded by the National Science Foundation and the National Institutes of Health.
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