Science & Tech News
NASA, ATK successfully test largest and most powerful solid rocket motor
Washington, Sept 1: NASA and ATK Aerospace Systems have successfully completed a two-minute, full-scale test of the largest and most powerful solid rocket motor designed for flight.
The stationary firing of the first-stage development solid rocket motor, dubbed DM-2, was the most heavily instrumented solid rocket motor test in NASA history.
To verify the performance of new materials and assess motor performance at low temperatures, the solid rocket motor was cooled to 40 degrees Fahrenheit.
"Ground-testing at temperature extremes pushes this system to its limits, which advances our understanding of five-segment solid rocket motor performance." said Alex Priskos.
The five-segment development motor includes several upgrades and technology improvements implemented by NASA and ATK engineers.
Motor upgrades from a shuttle booster include the addition of a fifth segment, a larger nozzle throat, and upgraded insulation and liner. The motor cases are flight-proven hardware used on shuttle launches for more than three decades. The cases used in this ground test have collectively launched 59 previous missions, the earliest being STS-3.
After more testing, the first-stage solid rocket motor will be certified to fly at temperature ranges between 40-90 degrees Fahrenheit. (ANI)
Is it possible to predict future climate change?
Washington, Aug 31: Climate change is a topic for hot debate across countries right now, but is it possible to predict future climate change?
Researchers at Niels Bohr Institute at the University of Copenhagen said that climate change probably occurs as a result of different chaotic influences and as a result would be difficult to predict.
The most pronounced climate shifts besides the end of the ice age is a series of climate changes during the ice age where the temperature suddenly rose 10-15 degrees in less than 10 years. The climate change lasted perhaps 1000 years, then - bang - the temperature fell drastically and the climate changed again.
This sudden change is called the tipping point and researchers have not been able to simulate it in their labs.
"We have made a theoretical modelling of two different scenarios that might trigger climate change. We wanted to investigate if it could be determined whether there was an external factor which caused the climate change or whether the shift was due to an accumulation of small, chaotic fluctuations", explained Peter Ditlevsen, a climate researcher at the Niels Bohr Institute.
According to Ditlevsen, in one scenario the climate is like a seesaw that has tipped to one side. If sufficient weight is placed on the other side the seesaw will tip - the climate will change from one state to another.
In the second scenario the climate is like a ball in a trench, which represents one climate state. Turmoil in the climate system such as storms, heat waves, heavy rainfall and the melting of ice sheets may finally push the ball over into the other trench, which represents a different climate state.
Currently, an increase in the atmospheric content of CO2 may be triggering a shift in the climate again.
"The Earth has not had such a high CO2 content in the atmosphere since more than 15 million years ago, when the climate was very warm and alligators lived in England," he said.
"This could mean that the climate might not just slowly gets warmer over the next 1000 years, but that major climate changes theoretically could happen within a few decades", Ditlevsen added, but stressed that his research only deals with investigating the climate of the past and not predictions of the future climate.
The results have just been published in Geophysical Research Letters. (ANI)
Malaria mosquitoes ‘use several kinds of odour sensors’
Washington, September 1, 2010: In what may help develop more effective repellents, scientists claim to have discovered that malaria mosquitoes use several different kinds of odour sensors to sniff out their human prey.
For years, it’s known that Anopheles gambiae -- the species of mosquito that spreads malaria which infects 250 million and kills 900,000 people annually -- use one family of odour sensors to track its human prey.
Now, a team at Vanderbilt University has found that the mosquitoes possess a second set of olfactory sensors that are fundamentally different from the set of sensors which was known to researchers for the last 10 years, the latest edition of the ‘Public Library of Science Biology’ journal reported.
According to the scientists, they also have preliminary evidence that the mosquito’s olfactory system may include additional families of sensors as well.
“It’s not at all surprising that the mosquito’s olfactory system is more sophisticated than thought. Olfaction is absolutely essential to the mosquito. If the female cannot find a host for a blood meal she cannot reproduce.
“As a result, mosquitoes have developed an uncanny ability to detect odours. This is true of all species of mosquitoes, not just Anopheles.
“So it is highly likely that the mosquitoes that spread West Nile, dengue fever, yellow fever and encephalitis also have similar odour sensors,” Laurence Zwiebel, who led the team, said.
According to the scientists, the discovery may help explain a puzzling question that has been plaguing researchers trying to develop new and more effective forms of mosquito lures and repellents.
“The odorant receptors that were identified in the lab before don’t respond to a lot of human odours. Now that we have a new set of receptors we may be able to fill in the picture,” team member Chao Liu said.
There is a good chance that this new set of receptors may be specifically tuned to detect a number of the odorants given off by humans, added team member R Jason Pitts.
“If this is the case then it is quite likely that it will play a critical role in attempts to develop improved lures and repellents to control the spread of malaria,” he said.
In their research, the scientists combined gene-silencing techniques with a new behavioural assay to confirm that DEET, the most commonly used commercial insect repellent, activates of a specific AgOR.
Although the synthetic compound appears to effect mosquitoes in several different ways, there is no doubt that this olfactory effect explains much of its effectiveness as a repellent, say the scientists.
They identified genes that code for about 50 versions of the new type receptor. The new receptors appear to have a slightly different structure from that of AgORs -- they are called “ionotropic receptors” and they closely resemble the type of receptor found in the brain that responds to the common neurotransmitter, glutamate.
At this point, the researchers can only speculate about what effect this structural difference has on the way that the AgIRs function as odour detectors. However, they have managed to associate an AgIR with butylamine, a human odorant that AgORs do not appear to identify.
Culprit behind severe allergic asthma discovered
London, Aug 30: Researchers from Cincinnati Children's Hospital Medical Center have identified the key culprit behind severe asthma-like symptoms in mice.
The disease can be triggered in susceptible people by a variety of environmental contaminants - such as cigarette smoke, allergens and airborne pollution.
Dr. Marsha Wills-Karp and her colleagues have identified the pro-inflammatory protein, interleukin-17 (IL-17A), as the molecular tipping point that upsets a delicate balance between underlying mild disease and more severe asthma, reports Nature.
Airway exposure to environmental allergens causes dysfunctional regulation of a gene called complement factor 3 (C3). This leads to overzealous production of IL-17A by airway cells and sets off what the scientists describe as an "amplification loop," when IL-17A in turn induces more C3 production at the airway surface.
The amplification loop perpetuates increasing inflammatory responses as well as airway hyper-responsiveness and airflow obstruction.
As the team continues their research, they will study the relationship between C3 and IL-17A in severe asthmatics, and explore the effectiveness of targeting either the C3 or IL-17A pathways for the treatment of severe asthma.
The study is published in the latest Nature Immunology. (ANI)
Star Trek theme song ruling NASA's space song poll
Melbourne, Aug 31: Alexander Courage's Star Trek Theme Song is leading the way in NASA's space song poll.
NASA is currently running an online poll to let the public choose two wake-up songs to be played to the crew of flight STS-133, due to launch on November 1.
Voters can choose from 40 tracks played to previous NASA crews, including galactic-themed pop songs like Frank Sinatra's recording of 'Fly Me To The Moon' and 'Here Comes The Sun' by The Beatles.
But the most popular choice is the Star Trek theme by Courage with 400,000 votes, reports News.com.au.
On the other hand, its sci-fi flick rival, Theme From Star Wars Trilogy by John Williams, has just 10,000 votes.
The other most voted-for songs offer a peek into the music taste of space nerds, with Steppenwolf's Magic Carpet Ride and Countdown by Rush coming in at number two and three.
STS-133 will be NASA's 113th space shuttle flight.
The crew will travel aboard Discovery to the International Space Station to deliver spare components and install a new module.
Other than letting people choose which songs will be played on flight STS-133, the space agency is calling on songwriters to submit original work for the next flight.
Entrants have until January 10 to submit a song of their creation to be played to the crew of STS-134. (ANI)
|
