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Joris _

Six days left for Hayabusa: A recap of the mission - The Planetary Society Blog | The P... - 1 views

www.planetary.org/...00002530

MAD

shared by Joris _ on 09 Jun 10 - Cached
  • Joris _ on 09 Jun 10
     
    a nice recap' of Hayabusa mission
Friederike Sontag

Retooling the ocean conveyor belt - 1 views

www.sciencedaily.com/...100618102646.htm

ocean_circulation

shared by Friederike Sontag on 23 Jun 10 - Cached
  • Climate Ecosystems Reference Ocean current Atmospheric circulation Gulf Stream Mid-ocean ridge In a paper in the June 18 issue of Science, a Duke University oceanographer reviews the growing body of evidence that suggests it's time to rethink the conveyor belt model. "The old model is no longer valid for the ocean's overturning, not because it's a gross simplification, but because it i
  • Friederike Sontag on 23 Jun 10
     
    "The old model is no longer valid for the ocean's overturning, not because it's a gross simplification, but because it ignores crucial elements such as eddies and the wind field. The concept of a conveyor belt for the overturning was developed decades ago, before oceanographers had measured the eddy field of the ocean and before they understood how energy from the wind impacts the overturning,"
Giusi Schiavone

The importance of stupidity in scientific research. - 10 views

jcs.biologists.org/...1771

shared by Giusi Schiavone on 07 Sep 10 - Cached
  • Giusi Schiavone on 07 Sep 10
     
    I suggest you this easy reading ( is on a peer-reviewed scientific journal, IF = 6.14) 'We just don't know what we're doing!!!'
  • ...2 more comments...
  • LeopoldS on 08 Sep 10
     
    as a start of a peer reviewed paper this is an interesting first paragraph: "I recently saw an old friend for the first time in many years. We had been Ph.D. students at the same time, both studying science, although in different areas. She later dropped out of graduate school, went to Harvard Law School and is now a senior lawyer for a major environmental organization. At some point, the conversation turned to why she had left graduate school. To my utter astonishment, she said it was because it made her feel stupid. After a couple of years of feeling stupid every day, she was ready to do something else."
  • Ma Ru on 08 Sep 10
     
    Hilarious! Mr Schwartz, who made a PhD at Stanford(!) and apparently is working as a postdoc now, has finally discovered what science is about!!! Quote: "That's when it hit me: nobody did. That's why it was a research problem." And he seems so excited about it! I think he should not only get published in 6.14 journal, but also get the Nobel Prize immediately! Seriously, after reading something like this, how one may not have superstitions about the educational system in the US?
  • LeopoldS on 10 Sep 10
     
    I tend to agree with you but I think that you are too harsh - its still only an "essay" and one of his points of making sure that education at post graduate level is not about indoctrinating what we know already is valid ...
  • Francesco Biscani on 20 Sep 10
     
    I think this quote by Richard Horton is relevant to the discussion: "We portray peer review to the public as a quasi-sacred process that helps to make science our most objective truth teller. But we know that the system of peer review is biased, unjust, unaccountable, incomplete, easily fixed, often insulting, usually ignorant, occasionally foolish, and frequently wrong." :P
pacome delva

Penrose claims to have glimpsed universe before Big Bang - 0 views

physicsworld.com/...44388

phy cosmology

shared by pacome delva on 22 Nov 10 - No Cached
LeopoldS liked it
  • According to Penrose and Gurzadyan, these circles allow us to "see through" the Big Bang into the aeon that would have existed beforehand. The circles, they say, are the marks left in our aeon by the spherical ripples of gravitational waves that were generated when black holes collided in the previous aeon.
  • Julian Barbour, a visiting professor of physics at the University of Oxford, says that these circles would be "remarkable if real and sensational if they confirm Penrose's theory". They would, he says, "overthrow the standard inflationary picture", which, he adds, has become widely accepted as scientific fact by many cosmologists. But he believes that the result will be "very controversial" and that other researchers will look at the data very critically. He says there are many disputable aspects to the theory
  • pacome delva on 22 Nov 10
     
    hehe, a nice controversy? or completely overinterpreted results...?
  • LeopoldS on 23 Nov 10
     
    what the heck is this? sounds strange to me ... would I understand the original paper?
Giusi Schiavone

Telomerase reactivation reverses tissue degeneration in aged telomerase-deficient mice ... - 0 views

www.nature.com/...nature09603.html

tissue degeneration

shared by Giusi Schiavone on 16 Dec 10 - No Cached
  • Nature | Letter Previous article Next article Telomerase reactivation reverses tissue degeneratio
Dario Izzo

Probabilistic Logic Allows Computer Chip to Run Faster - 3 views

www.azonano.com/news.asp

INF MAD probabilistic computing AI

shared by Dario Izzo on 07 Dec 09 - Cached
  • Dario Izzo on 07 Dec 09
     
    Francesco pointed out this research one year ago, we dropped it as noone was really considering it ... but in space a low CPU power consumption is crucial!! Maybe we should look back into this?
  • ...6 more comments...
  • Ma Ru on 07 Dec 09
     
    Q1: For the time being, for what purposes computers are mainly used on-board?
  • Dario Izzo on 07 Dec 09
     
    for navigation, control, data handling and so on .... why?
  • Ma Ru on 07 Dec 09
     
    Well, because the point is to identify an application in which such computers would do the job... That could be either an existing application which can be done sufficiently well by such computers or a completely new application which is not already there for instance because of some power consumption constraints... Q2 would be then: for which of these purposes strict determinism of the results is not crucial? As the answer to this may not be obvious, a potential study could address this very issue. For instance one can consider on-board navigation systems with limited accuracy... I may be talking bullshit now, but perhaps in some applications it doesn't matter whether a satellite flies on the exact route but +/-10km to the left/right? ...and so on for the other systems. Another thing is understanding what exactly this probabilistic computing is, and what can be achieved using it (like the result is probabilistic but falls within a defined range of precision), etc. Did they build a complete chip or at least a sub-circiut, or still only logic gates...
  • Dario Izzo on 07 Dec 09
     
    Satellites use old CPUs also because with the trend of going for higher power modern CPUs are not very convenient from a system design point of view (TBC)... as a consequence the constraints put on on-board algorithms can be demanding. I agree with you that double precision might just not be necessary for a number of applications (navigation also), but I guess we are not talking about 10km as an absolute value, rather to a relative error that can be tolerated at level of (say) 10^-6. All in all you are right a first study should assess what application this would be useful at all.. and at what precision / power levels
  • Joris _ on 07 Dec 09
     
    The interest of this can be a high fault tolerance for some math operations, ... which would have for effect to simplify the job of coders! I don't think this is a good idea regarding power consumption for CPU (strictly speaking). The reason we use old chip is just a matter of qualification for space, not power. For instance a LEON Sparc (e.g. use on some platform for ESA) consumes something like 5mW/MHz so it is definitely not were an engineer will look for some power saving considering a usual 10-15kW spacecraft
  • Dario Izzo on 07 Dec 09
     
    What about speed then? Seven time faster could allow some real time navigation at higher speed (e.g. velocity of a terminal guidance for an asteroid impactor is limited to 10 km/s ... would a higher velocity be possible with faster processors?) Another issue is the radiation tolerance of the technology ... if the PCMOS are more tolerant to radiation they could get more easily space qualified.....
  • Joris _ on 08 Dec 09
     
    I don't remember what is the speed factor, but I guess this might do it! Although, I remember when using an IMU that you cannot have the data above a given rate (e.g. 20Hz even though the ADC samples the sensor at a little faster rate), so somehow it is not just the CPU that must be re-thought. When I say qualification I also imply the "hardened" phase.
  • Francesco Biscani on 08 Dec 09
     
    I don't know if the (promised) one-order-of-magnitude improvements in power efficiency and performance are enough to justify looking into this. For once, it is not clear to me what embracing this technology would mean from an engineering point of view: does this technology need an entirely new software/hardware stack? If that were the case, in my opinion any potential benefit would be nullified. Also, is it realistic to build an entire self-sufficient chip on this technology? While the precision of floating point computations may be degraded and still be useful, how does all this play with integer arithmetic? Keep in mind that, e.g., in the Linux kernel code floating-point calculations are not even allowed/available... It is probably possible to integrate an "accelerated" low-accuracy floating-point unit together with a traditional CPU, but then again you have more implementation overhead creeping in. Finally, recent processors by Intel (e.g., the Atom) and especially ARM boast really low power-consumption levels, at the same time offering performance-boosting features such as multi-core and vectorization capabilities. Don't such efforts have more potential, if anything because of economical/industrial inertia?
pacome delva

Fruit Fly Aerial Maneuver Explained - 1 views

focus.aps.org/st13

bio biomimicry fruit_fly

shared by pacome delva on 12 Apr 10 - Cached
LeopoldS liked it
  • Insects can execute flying feats more impressive than fighter jets, and a team of researchers has now learned the trick behind one of them. They used high speed video cameras and a new 3D reconstruction technique to show how fruit flies execute their acrobatic turns. As they report in the 9 April Physical Review Letters, despite the complex wing motions, a fly can execute quick pirouettes by adjusting just a single parameter that controls the difference between the way its left and right wings oscillate. The results may be relevant for engineers designing flight control strategies for tiny robotic insects for search-and-rescue and surveillance.
pacome delva

Physicists study how moral behaviour evolved - 2 views

physicsworld.com/...42540

phy ia cooperation

shared by pacome delva on 07 May 10 - Cached
  • A statistical-physics-based model may shed light on the age-old question "how can morality take root in a world where everyone is out for themselves?" Computer simulations by an international team of scientists suggest that the answer lies in how people interact with their closest neighbours rather than with the population as a whole.
  • pacome delva on 07 May 10
     
    Reminds me something... :)
  • nikolas smyrlakis on 07 May 10
     
    I check diigo for the first time since I left and my spirit is still there yeah !
Luís F. Simões

William Shatner Wakes Up Crew for Final Discovery Mission - Slashdot - 1 views

idle.slashdot.org/...ew-for-Final-Discovery-Mission

Space shuttle sci-fi Star Trek fun

shared by Luís F. Simões on 07 Mar 11 - No Cached
  • The Space Shuttle Discovery left the International Space Station this morning for the last time. To commemorate the ship's accomplishments over 27 years of service, the crew was greeted to a morning wake-up message from Capt. Kirk. "Space, the final frontier," Shatner said in a prerecorded message. "These have been the voyages of the space shuttle Discovery. Her 30-year mission: to seek out new science, to build new outposts, to bring nations together on the final frontier, to boldly go and do what no spacecraft has done before."
  • Luís F. Simões on 07 Mar 11
     
    here's a recording of the transmission: http://ia600406.us.archive.org/13/items/STS-133/03-07-11_STS-133_FD12_Crew_Wakeup.mp3 to quote from the thread at reddit: "When the space shuttle first flew, 55 americans were being held hostage in the embassy in Iran, and Ronald Reagan had just become president. That same year Prince Charles would marry Lady Diana, the HIV virus would be first identified, Post-It notes were invented, and a small company called Microsoft released it's new operating system MS-DOS."
  • Francesco Biscani on 07 Mar 11
     
    Speaking of William Shatner, the legendary "Rocket Man": http://www.youtube.com/watch?v=5hARDXYz2io
ESA ACT

Three-dimensional left-handed material lens - 0 views

scitation.aip.org/...GetabsServlet

PHY Photonics optics

shared by ESA ACT on 24 Apr 09 - No Cached
  • ESA ACT on 24 Apr 09
     
    A model is provided for the image formation by a three-dimensional lens with negative index of refraction (n) and compared with results for an array of split-ring resonators (SRRs) and wires. For n=−1, a linear decrease in image distance r is expected w
Luís F. Simões

AI, Robotics, and the Future of Jobs | Pew Research Center's Internet & American Life P... - 0 views

www.pewinternet.org/...future-of-jobs

AI robotics

shared by Luís F. Simões on 05 Sep 14 - No Cached
Paul N liked it
  • Some 1,896 experts responded to the following question: The economic impact of robotic advances and AI—Self-driving cars, intelligent digital agents that can act for you, and robots are advancing rapidly. Will networked, automated, artificial intelligence (AI) applications and robotic devices have displaced more jobs than they have created by 2025?
  • Paul N on 08 Sep 14
     
    I mainly see neural networks in this... maybe some evolutionary stuff :))
annaheffernan

Acoustic topological insulator could hide submarines - 2 views

physicsworld.com/...nsulator-could-hide-submarines

technology science PHY

shared by annaheffernan on 30 Mar 15 - No Cached
  • annaheffernan on 30 Mar 15
     
    Researchers have proposed a new "acoustic topological insulator" that could help alleviate sound scattering problems by transmitting sound in certain directions without any backscattering.
  • Athanasia Nikolaou on 30 Mar 15
     
    If I understood correctly the triangular structure would channel the incident sound wave to a unique direction between two options, according to the rotation direction of the cylinders included in its mesh. So, one (possibly two) directions left to detect the hypothetical submarines? Very interesting though, I hope no oceanographers take measurements simultaneously to the signals as climate models will get even more wrong...!
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