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Not a scratch - 7 views

shared by pandomilla on 12 Apr 12 - No Cached
LeopoldS liked it
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    I hate scorpions, but this could be a nice subject for a future Ariadna study! This north African desert scorpion, doesn't dig burrows to protect itself from the sand-laden wind (as the other scorpions do). When the sand whips by at speeds that would strip paint away from steel, the scorpion is able to scurry off without apparent damage.
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    Nice research, though they have done almost all the work that we could do in an Ariadna, didnt they? "To check, they took further photographs. In particular, they used a laser scanning system to make a three-dimensional map of the armour and then plugged the result into a computer program that blasted the virtual armour with virtual sand grains at various angles of attack. This process revealed that the granules were disturbing the air flow near the skeleton's surface in ways that appeared to be reducing the erosion rate. Their model suggested that if scorpion exoskeletons were smooth, they would experience almost twice the erosion rate that they actually do. Having tried things out in a computer, the team then tried them for real. They placed samples of steel in a wind tunnel and fired grains of sand at them using compressed air. One piece of steel was smooth, but the others had grooves of different heights, widths and separations, inspired by scorpion exoskeleton, etched onto their surfaces. Each sample was exposed to the lab-generated sandstorm for five minutes and then weighed to find out how badly it had been eroded. The upshot was that the pattern most resembling scorpion armour-with grooves that were 2mm apart, 5mm wide and 4mm high-proved best able to withstand the assault. Though not as good as the computer model suggested real scorpion geometry is, such grooving nevertheless cut erosion by a fifth, compared with a smooth steel surface. The lesson for aircraft makers, Dr Han suggests, is that a little surface irregularity might help to prolong the active lives of planes and helicopters, as well as those of scorpions."
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    What bugs me (pardon the pun) is that the dimensions of the pattern they used were scaled up by many orders of magnitude, while "grains of sand" with which the surface was bombarded apparently were not... Not being a specialist in the field, I would nevertheless expect that the size of the surface pattern *in relation to* to size of particles used for bombarding would be crucial.
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'Designer' graphene makes its debut - physicsworld.com - 1 views

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    Researchers in the US have created the first artificial samples of graphene with electronic properties that can be controlled in a way not possible in the natural form of the material.
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Tests of Parents Are Used to Map Genes of a Fetus - NYTimes.com - 0 views

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    "For the first time, researchers have determined virtually the entire genome of a fetus using only a blood sample from the pregnant woman and a saliva specimen from the father."
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Sex differences in the structural connectome of the human brain - 0 views

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    it seems that there are indications that we are differently wired .... Sex differences in human behavior show adaptive complementarity: Males have better motor and spatial abilities, whereas females have superior memory and social cognition skills. Studies also show sex differences in human brains but do not explain this complementarity. In this work, we modeled the structural connectome using diffusion tensor imaging in a sample of 949 youths (aged 8-22 y, 428 males and 521 females) and discovered unique sex differences in brain connectivity during the course of development. Connection-wise statistical analysis, as well as analysis of regional and global network measures, presented a comprehensive description of network characteristics. In all supratentorial regions, males had greater within-hemispheric connectivity, as well as enhanced modularity and transitivity, whereas between-hemispheric connectivity and cross-module participation predominated in females. However, this effect was reversed in the cerebellar connections. Analysis of these changes developmentally demonstrated differences in trajectory between males and females mainly in adolescence and in adulthood. Overall, the results suggest that male brains are structured to facilitate connectivity between perception and coordinated action, whereas female brains are designed to facilitate communication between analytical and intuitive processing modes.
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    I like this abstract: sex, sex, sex, sex, SEX, SEX, SEX, SEX...!!! I wonder if the "sex differences" are related to gender-specific differences...
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Soundsnap.com: Find and Share Free Sound Effects and Loops - 0 views

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    "Soundsnap is the best platform to find and share free sound effects and loops- legally. It is a collection of original sounds made or recorded by its users, and not songs or sound FX found on commercial libraries or sample CD's."
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OpenBCI - 5 views

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    "The OpenBCI Board is a versatile and affordable analog-to-digital converter that can be used to sample electrical brain activity (EEG), muscle activity (EMG), heart rate (EKG), and more" Perhaps some work or ideas on brainwave analysis would be interesting ? (User interfaces, mood classifier, detection of various alertness levels )
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    lets get one? And then link to the Oculus Rift to control it with my brain.. I want to think about running on Mars and then be doing it :)
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    It's not worth it for $400... The chips are seriously nothing special and you can get a lot better for a lot cheaper. I would just get the electrodes and link them to a RPi or an Odroid or something.
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    True, but the selling feature here is that they take care of that stuff and sell it for 400$. Lets say the hardware is 100USD, then an RF-grade person here here has to do the coding, interfacing, testing within roughly (300/16eur/hour) 20 hours to break even and even then the interface is much nicer in their case.
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Accelerated search for materials with targeted properties by adaptive design - 0 views

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    There has been much recent interest in accelerating materials discovery. High-throughput calculations and combinatorial experiments have been the approaches of choice to narrow the search space. The emphasis has largely been on feature or descriptor selection or the use of regression tools, such as least squares, to predict properties. The regression studies have been hampered by small data sets, large model or prediction uncertainties and extrapolation to a vast unexplored chemical space with little or no experimental feedback to validate the predictions. Thus, they are prone to be suboptimal. Here an adaptive design approach is used that provides a robust, guided basis for the selection of the next material for experimental measurements by using uncertainties and maximizing the 'expected improvement' from the best-so-far material in an iterative loop with feedback from experiments. It balances the goal of searching materials likely to have the best property (exploitation) with the need to explore parts of the search space with fewer sampling points and greater uncertainty.
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NASA investigates sending CubeSats to Phobos and back - 3 views

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    NASA's Innovative Advanced Concepts Program provides funding to study a small number of highly advanced spaceflight concepts, with the goal of understanding the technological possibilities which will guide the development of future space missions. Under this program, a JPL (Jet Propulsion Laboratory) researcher has proposed the use of a pair of CubeSats for an autonomous mission to retrieve samples from Phobos, Mars' larger moon.
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[1107.5728] The network of global corporate control - 1 views

  • Abstract: The structure of the control network of transnational corporations affects global market competition and financial stability. So far, only small national samples were studied and there was no appropriate methodology to assess control globally. We present the first investigation of the architecture of the international ownership network, along with the computation of the control held by each global player. We find that transnational corporations form a giant bow-tie structure and that a large portion of control flows to a small tightly-knit core of financial institutions. This core can be seen as an economic "super-entity" that raises new important issues both for researchers and policy makers.
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Snake Robots for Exploration - 1 views

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    The researchers are busy working on a feasibility study assigned to them by the ESA. The idea is that by combining a rover that can navigate over large distances with a snake robot that can crawl along the ground and can get into inaccessible places, so many more possibilities could be opened up, e.g. collecting samples from tight spots that the rovers cannot reach.
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Science on Mars and Mars on Science - 0 views

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    Some sort of organic carbon has been detected by the sampling of Curiosity; the contamination source was isolated and the signal persists. The scientists suggest as a source meteorites transporting interstellar matter, or maybe some sort of ancient life whose biomass production only survived cosmic radiation as it was buried underground. a big deal: six relevant articles were published simultaneously online: http://www.sciencemag.org/site/extra/curiosity/index.xhtml?utm_content=&utm_medium=Facebook&utm_campaign=Science&utm_source=shortener
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Plant sciences: Plants drink mineral water : Nature : Nature Publishing Group - 1 views

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    Here we go: we might not need liquid water after all on mars to get some nice flowering plants there! ... and terraform ? :-) Thirsty plants can extract water from the crystalline structure of gypsum, a rock-forming mineral found in soil on Earth and Mars.

    Some plants grow on gypsum outcrops and remain active even during dry summer months, despite having shallow roots that cannot reach the water table. Sara Palacio of the Pyrenean Institute of Ecology in Jaca, Spain, and her colleagues compared the isotopic composition of sap from one such plant, called Helianthemum squamatum (pictured), with gypsum crystallization water and water found free in the soil. The team found that up to 90% of the plant's summer water supply came from gypsum.

    The study has implications for the search for life in extreme environments on this planet and others.

    Nature Commun 5, 4660 (2014)
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    Very interesting indeed. Attention is to be put on the form of calcium sulfate that is found on Mars. If it is hydrated (gypsum Ca(SO4)*2(H2O)) it works, but if it is dehydrated there is no water for the roots to take in. The Curiosity Rover tries to find out, but has uncertainty in recognising the hydrogen presence in the mineral: Copying : "(...) 3.2 Hydration state of calcium sulfates Calcium sulfates occur as a non-hydrated phase (anhydrite, CaSO4) or as one of two hydrated phases (bassanite, CaSO4.1/2H2O, which can contain a somewhat variable water content, and gypsum, CaSO4.2H2O). ChemCam identifies the presence of hydrogen at 656 nm, as already found in soils and dust [Meslin et al., 2013] and within fluvial conglomerates [Williams et al., 2013]. However, the quantification of H is strongly affected by matrix effects [Schröder et al., 2013], i.e. effects including major or even minor element chemistry, optical and mechanical properties, that can result in variations of emission lines unrelated to actual quantitative variations of the element in question in the sample. Due to these effects, discriminating between bassanite and gypsum is difficult. (...)"
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Space capsule probed for asteroid dust : Nature News - 1 views

  • They have clearly shown us the path forward to the inevitable large-scale exploration of the near-Earth asteroid population
  • Interest in asteroid missions has also been on the rise in the United States. In June, US President Barack Obama called for a manned trip to an asteroid. And late last year, the OSIRIS-REx project, also a sample-return mission targeting a carbon-rich asteroid, was selected as a finalist in NASA's New Frontiers Program,
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Hayabusa Sample Return Capsule Entry - Airborne Observing Campaign - 0 views

  • An attempt will be made to provide a live video feed of the Hayabusa Re-Entry in the minutes around the re-entry at 13:51 UT, Sunday June 13. The video will be chosen from cameras operated onboard NASA's DC-8 Airborne Laboratory
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    After reading the Hayabusa's story posted by Joris a while ago, I think that the only adequately epic final to conclude this awesome mission is that the capsule will land safely. And empty.
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JAXA releases pictures of dust found in Hayabusa space probe sample capsule - The Maini... - 1 views

  • The capsule was not empty, and it means a lot.
  • 10 particles of about 1 millimeter in size
  • The detected particles will be compared with terrestrial materials
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OpenLuna Picks Up Where NASA's Moon Mission Leaves Off - 0 views

  • The ambitious project will tap the resources of private enterprise to build several small scout rovers that will be shipped to the south pole of the moon via a single lander. Rock and earth samples will be returned to Earth for testing, then auctioned off to secure funding for the next phase of the plan
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Probabilistic Logic Allows Computer Chip to Run Faster - 3 views

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    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?
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    Q1: For the time being, for what purposes computers are mainly used on-board?
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    for navigation, control, data handling and so on .... why?
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    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...
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    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
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    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
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    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.....
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    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.
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    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?
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Animal personalities: Unnatural selection | The Economist - 0 views

  • the first time that differences in personality have been shown in wild birds
  • hese analyses are based on the assumption that the animals collected represent a randomly selected and thus representative sample of the population.
  • Instead it looks as if such trapping studies are selecting the bravest individuals.
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    What if heuristic algorithms (PSO, DE, ...) do not actually simulate flocking birds or school gish beahviour ?!
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Interfacing Silicon Nanowires with Mammalian Cells - 0 views

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    The title says it all - now we just need to make nerve cells and establish electric circuits.
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