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Mars Base

NASA beams Mona Lisa to Lunar Reconnaissance Orbiter at the moon (w/ video) - 0 views

phys.org/...lisa-lunar-reconnaissance.html

scibyte78

shared by Mars Base on 18 Jan 13 - No Cached
  • To clean up transmission errors introduced by Earth's atmosphere (left), Goddard scientists applied Reed-Solomon error correction (right), which is commonly used in CDs and DVDs.
  • Typical errors include missing pixels (white) and false signals (black). The white stripe indicates a brief period when transmission was paused
  • As part of the first demonstration of laser communication with a satellite at the moon, scientists with NASA's Lunar Reconnaissance Orbiter (LRO) beamed an image of the Mona Lisa to the spacecraft from Earth.
  • ...19 more annotations...
  • he iconic image traveled nearly 240,000 miles in digital form from the Next Generation Satellite Laser Ranging (NGSLR) station at NASA's Goddard Space Flight Center in Greenbelt, Md., to the Lunar Orbiter Laser Altimeter (LOLA) instrument on the spacecraft.
  • By transmitting the image piggyback on laser pulses that are routinely sent to track LOLA's position, the team achieved simultaneous laser communication and tracking.
  • This is the first time anyone has achieved one-way laser communication at planetary distances
  • "In the near future, this type of simple laser communication might serve as a backup for the radio communication that satellites use
  • In the more distant future, it may allow communication at higher data rates than present radio links can provide
  • Typically, satellites that go beyond Earth orbit use radio waves for tracking and communication
  • LRO is the only satellite in orbit around a body other than Earth to be tracked by laser as well.
  • Precise timing was the key to transmitting the image
  • divided the Mona Lisa image into an array of 152 pixels by 200 pixels
  • Every pixel was converted into a shade of gray, represented by a number between zero and 4,095.
  • Each pixel was transmitted by a laser pulse, with the pulse being fired in one of 4,096 possible time slots during a brief time window allotted for laser tracking
  • he complete image was transmitted at a data rate of about 300 bits per second.
  • The laser pulses were received by LRO's LOLA instrument, which reconstructed the image based on the arrival times of the laser pulses from Earth
  • This was accomplished without interfering with LOLA's primary task of mapping the moon's elevation and terrain and NGSLR's primary task of tracking LRO.
  • The success of the laser transmission was verified by returning the image to Earth using the spacecraft's radio telemetry system.
  • Turbulence in Earth's atmosphere introduced transmission errors even when the sky was clear.
  • To overcome these effects,
  • employed Reed-Solomon coding, which is the same type of error-correction code commonly used in CDs and DVDs.
  • The next step after LLCD is the Laser Communications Relay Demonstration (LCRD), NASA's first long-duration optical communications mission.
Mars Base

Mars Science Laboratory: Curiosity Out of Safe Mode - 0 views

mars.jpl.nasa.gov/...index.cfm

scibyte110

shared by Mars Base on 17 Nov 13 - No Cached
  • received confirmation from Mars
  • Nov. 10) that the Curiosity rover has successfully transitioned back into nominal surface operations mode
  • had been in safe mode since Nov. 7,
  • ...7 more annotations...
  • when an unexpected software reboot (also known as a warm reset) occurred during a communications
  • After analyzing the data returned by the spacecraft on
  • Nov. 7
  • Curiosity operations team was able to determine the root cause. An error in existing onboard software resulted in an error in a catalog file
  • This caused an unexpected reset when the catalog was processed by a new version of flight software which had been installed on Thursday
  • The team was able to replicate the problem on ground testbeds the following day
  • Commands recovering the spacecraft were uplinked to the spacecraft early Sunday
Mars Base

ISEE-3 Reboot Project Update: BULLSEYE! and More - Space College - 0 views

spacecollege.org/...-update-bullseye-and-more.html

scibyte133 ISEE-3

shared by Mars Base on 02 Jun 14 - No Cached
  • spacecraft has two transponders,
  • transponder A and Transponder B
  • Transponder B is normally the engineering telemetry transponder and transponder A is the ranging transponder
  • ...32 more annotations...
  • The final state of the spacecraft before was to have both of the transponders transmitters active and that is what people around the world have been tracking.
  • the spacecraft is set up with a lot of redundancy so you can use either transponder A or B to send telemetry or range
  • We tried several times to command the spacecraft's B transponder at 2041.9479 MHz into the mode where it normally sends engineering telemetry
  • did not work
  • Then we tried the same process on transponder A
  • modulation from the output of the telemetry system
  • The initial command was just to turn engineering telemetry on at 512 bits/second. This was successful.
  • successfully commanded the spacecraft into engineering telemetry mode.
  • initial verification
  • later
  • through the A transponder's receiver we commanded through the B transponder's command decoder to output engineering telemetry through transponder B's transmitter
  • verified so far the following systems on the spacecraft
  • 1. Transponder A receiver
  • 2. Transponder A's Command Decoder and Data Handling Unit
  • 3. Transponder B's Command Decoder and Data Handling Unit
  • tried to command the spacecraft into 64 bits/second mode, which was a mode that is much more complicated to set up and we did not get working successfully during the limited time that the spacecraft is visible from Arecibo
  • need to do this so that the smaller dishes at Morehead State and Bochum will have a positive signal margin so that we can record several hours of data
  • neither of the ISEE-3/ICE receivers had met their specification in testing
  • for -120 dbm sensitivity
  • receiver A was tested at about -114 dbm, and Receiver B at -111 dbm
  • after our end to end systems test we had an earthquake
  • how observations could be affected by vibrations in the dome structure as it translates during an observation and then that happened
  • later processed our first day's data dump from the spacecraft and we received 49 full frames of data at a bit rate of 512 bits/second
  • there were no errors on the downlink
  • milestones related to commanding and receiving data
  • 1. Successful commanding multiple times of ISEE-3/ICE
  • 2. Received engineering telemetry from both data multiplexing units on the spacecraft
  • 3. Successful demodulation on the ground of the received data, through the output of bits
  • 4. Verification of good data at 512 bits/sec, including frame synchronization, correct number of bits/frame, and with no errors, showing a very strong 30+ db link margin through Arecibo
  • If we can maneuver the spacecraft by June 17th we get the very small delta V number
  • this starts to climb rapidly as the spacecraft gets closer to the moon
  • cannot at this time rule out a lunar impact.
Mars Base

Science Retractions: Top 5 Withdrawn Studies Of 2012 - 0 views

www.huffingtonpost.com/...ithdrawn-papers_n_2353421.html

scibyte76 Retraction

shared by Mars Base on 01 Jan 13 - No Cached
  • Hyung-In Moon is a genius, says Hyung-In Moon
  • Korean scientist Hyung-In Moon took the concept of scientific peer review to a whole new level by reviewing his own papers under various fake names
  • Moon's research — which included a study on alcoholic liver disease and another on an anticancer plant substance — can't be trusted
  • ...33 more annotations...
  • admitted to falsifying data in some of his papers
  • , 35 of his papers have been retracted in 2012.
  • Peer review is a process in which scientific peers in the same field judge the merit of a submitted journal paper
  • editors at the Journal of Enzyme Inhibition and Medicinal Chemistry grew suspicious when four of his glowing reviews came back within 24 hours. Anyone who has ever submitted a paper for peer review knows that reviewers take weeks or months to reply
  • Math paper a big, fat zero
  • "In this study, a computer application was used to solve a mathematical problem"
  • Neither the one-sentence abstract
  • nor the co-author's e-mail address, ohm@budweiser.com
  • publishing this one-page gem entitled "A computer application in mathematics"
  • published in January 2010 but not retracted until April 2012, despite silly sentences such as "Computer magnification is a Universal computer phenomenon" and "This is a problematic problem."
  • retracted the paper because it "contains no scientific content." The editors chalked it up to "an administrative error
  • Maybe his failure doesn't feel better than success
  • The Dutch social psychologist Diederik Stapel
  • has found that,
  • failure sometimes feels better than success
  • The only problem is that his research appears to be either mostly or completely fabricated
  • work has appeared in top journals
  • his good looks and clever research topics made him a media darling
  • So far, 31 papers have been retracted
  • meat eaters are absolved: One of Stapel's studies, now suspected to be fabricated, found that meat eaters are more selfish and less social than vegetarians
  • Studies proposing a link between cellphone use and cancer often rely on weak statistics. This one just used fudged data
  • in 2008, scientists published a paper
  • stating that cellphones in standby mode lowered the sperm count and caused other adverse changes in the testicles of rabbits
  • although small and published in a rather obscure journal, made the news rounds.
  • In March 2012, the authors retracted the paper
  • the lead author didn't get permission from his two co-authors and, according to the retraction notice, there was a "lack of evidence to justify the accuracy of the data presented in the article."
  • Stem-cell cure for heart disease likely faked
  • biologist Shinya Yamanaka had just won the 2012 Nobel Prize for his discovery of induced pluripotent stem cells (iPS cells), which are adult cells that can be reprogrammed to their "embryonic" stage
  • claimed at a New York Stem Cell Foundation meeting in early October to have advanced this technology to cure a person with terminal heart failure
  • Two institutions listed as collaborating on Moriguchi's related papers
  • denied that any of Moriguchi's procedures took place there
  • origuchi has admitted only to making some "procedural" mistakes
  • He is sticking to his story, however, that one patient was cured … at a Boston hospital not yet named
Mars Base

Nearby Ancient Star is Almost as Old as the Universe - 0 views

www.universetoday.com/...-almost-as-old-as-the-universe

scibyte84

shared by Mars Base on 24 Feb 13 - No Cached
  • A metal-poor star located merely 190 light-years from the Sun is 14.46+-0.80 billion years old, which implies that the star is nearly as old as the Universe
  • results emerged from a new study
  • Such metal-poor stars are (super) important to astronomers because they set an independent lower limit for the age of the Universe
  • ...21 more annotations...
  • can be used to corroborate age estimates inferred by other means
  • In the past, analyses of globular clusters and the Hubble constant
  • yielded vastly different ages for the Universe, and were offset by billions of years
  • based on the microwave background and Hubble constant, but it must have formed soon after the big bang
  • Within the errors, the age of HD 140283 does not conflict with the age of the Universe, 13.77 ± 0.06 billion years
  • Metal-poor stars can be used to constrain the age of the Universe because metal-content is typically a proxy for age
  • Heavier metals are generally formed in supernova explosions, which pollute the surrounding interstellar medium.
  • Stars subsequently born from that medium are more enriched with metals than their predecessors
  • each successive generation becoming increasingly enriched
  • HD 140283 exhibits less than 1% the iron content of the Sun, which provides an indication of its sizable age.
  • had been used previously to constrain the age of the Universe, but uncertainties tied to its estimated distance (at that time) made the age determination somewhat imprecise
  • obtain a new and improved distance for HD 140283 using the Hubble Space Telescope (HST), namely via the trigonometric parallax approach
  • distance uncertainty for HD 140283 was significantly reduced by comparison to existing estimates, thus resulting in a more precise age estimate for the star
  • The reliability of the age determined is likewise contingent on accurately determining the sample’s metal content
  • analyses of globular clusters and the Hubble constant yielded vastly different ages for the Universe
  • discrepant ages stemmed partly from uncertainties in the cosmic distance scale
  • determination of the Hubble constant relied on establishing (accurate) distances to galaxies
  • One of the key objectives envisioned for HST was to reduce uncertainties associated with the Hubble constant to <10%, thus providing an improved estimate for the age of the Universe
  • the mean implying an age near ~14 billion years
  • Determining a reliable age for stars in globular clusters is likewise contingent on the availability of a reliable distance
  • the study reaffirms that there are old stars roaming the solar neighborhood which can be used to constrain the age of the Universe
Mars Base

Drug's 'double hit' overcomes leukaemia resistance - 0 views

medicalxpress.com/...drug-leukaemia-resistance.html

Cancer GrabBag

shared by Mars Base on 13 Jul 12 - No Cached
  • drug that uses a unique ‘double hit’ to kill leukaemia cells could be a potential new treatment for patients with acute myeloid leukaemia
  • 30 per cent of patients with AML have faults in the FLT3 gene
  • linked to more aggressive leukaemias and poor survival
  • ...16 more annotations...
  • drugs that target these faults are available, the disease eventually builds resistance, leaving treatments ineffective.
  • researchers at The Institute of Cancer Research (ICR) in London
  • developed a unique drug that targets AML cells in a “double hit”.
  • blocks the protein made by the faulty FLT3 gene along with another key protein – called Aurora kinase – which are both involved in driving cancer growth
  • healthy blood cells, FLT3 sends a signal to the cells telling them when to proliferate, while Aurora kinase plays a role in cell division
  • Leukaemia cells with faulty FLT3 can proliferate out of control
  • many cancer cells have higher levels of Aurora kinase, causing errors during cell division
  • drug is also unique because it can destroy cells even if they develop new faults in the FLT3 genes that would make them resistant to other inhibitors
  • There has been great interest in using FLT3 drugs to treat AML
  • effectiveness has been limited because leukaemia cells gain new mistakes in the FLT3 gene, causing resistance.
  • new drug has the potential to overcome this and has a range of possible uses in AML
  • those over 60 who don’t tolerate chemotherapy well, and also to treat  leukaemia patients who have relapsed
  • We’re excited about the potential of our new ‘double hit’ drug and are now planning to take it into clinical trials to see if it is effective in patients
  • faults that occur in the FLT3 gene cause rapid cell division
  • Each year around 2,380 people are diagnosed with AML in the UK
  • creating cells in the lab that mimic how drug resistance develops in AML the researchers were able to show that their new drug delivers a ‘double hit’ to halt cancer cells in their tracks
Mars Base

Cloned Horses Coming to the Olympics? - 0 views

news.nationalgeographic.com/...ondon-olympics-2012-equestrian

scibyte58 horse Olympics

shared by Mars Base on 04 Aug 12 - No Cached
  • July 2012 the Féderation Equestre Internationale (FEI) lifted a ban on cloned horses and their progeny competing in the Olympic Games
  • cloning isn't easy, it isn't cheap, and there are no guarantees that the clone will match the talent of the original
  • cloning process can cost more than a hundred thousand U.S. dollars.
  • ...16 more annotations...
  • first successfully cloned horse
  • was born in 2003
  • Today, there are only a few hundred equine clones, created mainly for breeding
  • a top stallion for in vitro fertilization can go for tens of thousands of dollars
  • most male horses in high-level competitions are geldings
  • a mare can bear only so many foals
  • most common use for cloned horses is to perpetuate genetic material. The original horse can travel and compete, while its copy becomes a full-time foal-making machine
  • 2007 the FEI's general assembly decided that cloning was "potentially against the spirit of sport in that it was unfair
  • key factor in the decision was the high price of cloning, which has since come
  • federation determined that the clones were only 98 percent copies of the originals
  • the error margin of a full 2 percent was what ultimately caused the FEI to overturn the ban
  • widely agreed that environment, training, nutrition, and relationship with the rider have an incalculable impact on the horse's performance
  • American Quarter Horse Association won't allow clones
  • Neither will the Jockey Club, which registers thoroughbreds in North America
  • FEI has been careful to emphasize that cloning is a breeding technique only
  • only 300-odd horses competing in the Olympics, clones have to battle their way to the top just as traditionally bred horses do.
Mars Base

Once Again, Physicists Debunk Faster-Than-Light Neutrinos - ScienceInsider - 0 views

news.sciencemag.org/...e-again-physicists-debunk.html

scibyte50 Neutrinos

shared by Mars Base on 11 Jun 12 - No Cached
  • Five different teams of physicists have now independently verified that elusive subatomic particles called neutrinos do not travel faster than light
  • instead of the nail in the coffin of faster-than-light neutrinos, the new suite of results is more like the sod planted atop their grave
  • OPERA team also discovered that a loose fiber optic cable had introduced a delay in their timing system that explained the effect
  • ...5 more annotations...
  • A month later
  • measured the speed of neutrinos fired from CERN and found that they travel at light speed, as predicted
  • Some OPERA team members thought the whole episode had besmirched the collaboration's reputation, and in March, two of the team's elected leaders lost a vote of no confidence and tendered their resignations.
  • Gran Sasso houses four particle detectors
  • All four have now found that the neutrino's speed is consistent with the speed of light
Mars Base

Why Teenagers Are So Impulsive | Science/AAAS | News - 0 views

news.sciencemag.org/...why-teenagers-are-so-impulsive

scibyte110

shared by Mars Base on 16 Nov 13 - No Cached
  • When teenagers successfully resist an urge in a common test of impulsivity, they show increased activation in a brain region associated with restraint
  • suggesting that their brains have to work harder to avoid acting on the impulse
  • Why do teens—especially adolescent males—commit crimes more frequently than adults
  • ...20 more annotations...
  • One explanation may be that as a group, teenagers react more impulsively to threatening situations than do children or adults
  • likely because their brains have to work harder to rein in their behavior
  • teenagers have a reputation for courting danger that is often attributed to immaturity or poor decision-making
  • If immaturity or lack of judgment were the only problem, however, one would expect that children, whose brains are at an even earlier stage of development
  • younger children tend to be more cautious than teenagers, suggesting that there is something unique about adolescent brain development that lures them to danger
  • It's hard to generalize about teenage impulsivity
  • some adolescents clearly have more self-control than many adults
  • a growing body of evidence suggests that, in general, teens specifically struggle to keep their cool in social situations
  • many crimes committed during adolescence involve emotionally fraught social situations
  • to test whether teens perform badly on a common impulsivity task when faced with social cues of threat
  • recruited 83 people, ranging in age from 6 to 29, to perform a simple "Go/No-Go" task
  • they watched a series of faces making neutral or threatening facial expressions flicker past on a computer screen
  • Each time the participants saw a neutral face, they were instructed to hit a button
  • They were also told to hold back from pressing the button when they saw a threatening face
  • As the participants performed the task, the researchers monitored their brain activity with functional magnetic resonance imaging.
  • teenagers made about 15% more errors than adults and children when attempting to stop themselves from pressing the button when they saw the threatening facial expression
  • Males performed worse than females, suggesting a sex difference that fits with the disproportionate number of crimes that male teens commit,
  • adolescents who did manage to restrain themselves showed significantly higher activity in a brain region called the ventromedial prefrontal cortex (vmPFC), which is involved in top-down control of behavior
  • think of it as the break
  • the teenage brain might need to work a little harder to hold that response back
Mars Base

Study gives new meaning to 'let your fingers do the walking' - 0 views

medicalxpress.com/...2013-12-fingers.html

scibyte112

shared by Mars Base on 05 Dec 13 - No Cached
  • conclusion of a study conducted by a team of cognitive psychologists
  • When you are typing away at your computer, you don't know what your fingers are really doing
  • It found that skilled typists can't identify the positions of many of the keys on the QWERTY keyboard and that novice typists don't appear to learn key locations in the first place
  • ...19 more annotations...
  • we're capable of doing extremely complicated things without knowing explicitly what we are doing
  • The researchers recruited 100 university students and members from the surrounding community to participate in an experiment
  • The participants completed a short typing test
  • Then, they were shown a blank QWERTY keyboard and given 80 seconds to write the letters in the correct location
  • On average, they typed 72 words per minute, moving their fingers to the correct keys six times per second with 94 percent accuracy
  • By contrast, they could accurately place an average of only 15 letters on a blank keyboard.
  • The fact that the typists did so poorly at identifying the position of specific keys didn't come as a surprise
  • For more than a century, scientists have recognized the existence of automatism: the ability to perform actions without conscious thought or intention
  • Automatic behaviors of this type are surprisingly common, ranging from tying shoelaces to making coffee to factory assembly-line work to riding a bicycle and driving a car
  • What did come as a surprise, however, was evidence that conflicts with the basic theory of automatic learning which holds that it starts out as a conscious process and gradually becomes unconscious with repetition
  • According to the widely held theory, when you perform a new task or the first time, you are conscious of each action and store the details in working memory
  • Then, as you repeat the task, it becomes increasingly automatic
  • This allows you to think about other things while you performing the task but your conscious recollection of the details gradually fades away
  • researchers were surprised when they found evidence that the typists never appear to memorize the key positions, not even when they are first learning to type.
  • Evidence for this conclusion came from another experiment included in the study
  • The researchers recruited 24 typists who were skilled on the QWERTY keyboard and had them learn to type on a Dvorak keyboard, which places keys in different locations.
  • After the participants developed a reasonable proficiency with the alternative keyboard, they were asked to identify the placement of the keys on a blank Dvorak keyboard
  • On average, they could locate only 17 letters correctly, comparable to participants' performance with the QWERTY keyboard.
  • According to the researchers, the lack of explicit knowledge of the keyboard may be due to the fact that computers and keyboards have become so ubiquitous that students learn how to use them in an informal, trial-and-error fashion when they are very young
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