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jaihobah

The Nanodevice Aiming to Replace the Field Effect Transistor - 2 views

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    very nice! "For a start, the wires operate well as switches that by some measures compare well to field effect transistors. For example they allow a million times more current to flow when they are on compared with off when operating at a voltage of about 1.5 V. "[A light effect transistor] can replicate the basic switching function of the modern field effect transistor with competitive (and potentially improved) characteristics," say Marmon and co. But they wires also have entirely new capabilities. The device works as an optical amplifier and can also perform basic logic operations by using two or more laser beams rather than one. That's something a single field effect transistor cannot do."
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    The good thing about using CdSe NW (used here) is that they show a photon-to-current efficiency window around the visible wavelengths, therefore any visible light can in principle be used in this application to switch the transistor on/off. I don't agree with the moto "Nanowires are also simpler than field effect transistors and so they're potentially cheaper and easier to make." Yes, they are simple, yet for applications, fabricating devices with them consistently is very challenging (being the research effort not cheap at all..) and asks for improvements and breakthroughs in the fabrication process.
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    any idea how the shine the light selectively to such small surfaces?
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    "Illumination sources consisted of halogen light, 532.016, 441.6, and 325 nm lasers ported through a Horiba LabRAM HR800 confocal Raman system with an internal 632.8 nm laser. Due to limited probe spacing for electrical measurements, all illumination sources were focused through a 50x long working distance (LWD) objective lens (N.A. = 0.50), except 325 nm, which went through a 10x MPLAN objective lens (N.A. = 0.25)." Laser spot size calculated from optical diffraction formula 1.22*lambda/NA
LeopoldS

PLOS ONE: Galactic Cosmic Radiation Leads to Cognitive Impairment and Increas... - 1 views

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    Galactic Cosmic Radiation consisting of high-energy, high-charged (HZE) particles poses a significant threat to future astronauts in deep space. Aside from cancer, concerns have been raised about late degenerative risks, including effects on the brain. In this study we examined the effects of 56Fe particle irradiation in an APP/PS1 mouse model of Alzheimer's disease (AD). We demonstrated 6 months after exposure to 10 and 100 cGy 56Fe radiation at 1 GeV/µ, that APP/PS1 mice show decreased cognitive abilities measured by contextual fear conditioning and novel object recognition tests. Furthermore, in male mice we saw acceleration of Aβ plaque pathology using Congo red and 6E10 staining, which was further confirmed by ELISA measures of Aβ isoforms. Increases were not due to higher levels of amyloid precursor protein (APP) or increased cleavage as measured by levels of the β C-terminal fragment of APP. Additionally, we saw no change in microglial activation levels judging by CD68 and Iba-1 immunoreactivities in and around Aβ plaques or insulin degrading enzyme, which has been shown to degrade Aβ. However, immunohistochemical analysis of ICAM-1 showed evidence of endothelial activation after 100 cGy irradiation in male mice, suggesting possible alterations in Aβ trafficking through the blood brain barrier as a possible cause of plaque increase. Overall, our results show for the first time that HZE particle radiation can increase Aβ plaque pathology in an APP/PS1 mouse model of AD.
Ma Ru

Error Undoes Faster-Than-Light Neutrino Results - 3 views

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    :-)
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    And this guy is 200 bucks ahead http://xkcd.com/955/
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    Well, it's not yet confirmed... That error would be worse than the magnetic moment of the muon about 10 years ago. There, it was "at least" a conflict of conventions used in the computer codes!
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    In a statement based on an earlier press release from the OPERA collaboration, CERN said two possible "effects" may have influenced the anomalous measurements. One of them, due to a possible faulty connection between the fiber-optic cable bringing the GPS signals to OPERA and the detector's master clock, would have caused the experiment to underestimate the neutrinos' flight time, as described in the original story. The other effect concerns an oscillator, part of OPERA's particle detector that gives its readings time stamps synchronized to GPS signals. Researchers think correcting for an error in this device would actually increase the anomaly in neutrino velocity, making the particles even speedier than the earlier measurements seemed to show. CERN's statement says OPERA scientists are studying the "potential extent of these two effects" but doesn't indicate which source of error (if either) is likely to outweigh the other. However, Lucia Votano, director of the Gran Sasso laboratory, says the "main suspicion" focuses on the optical-fiber connection. She adds that OPERA researchers deserve credit for "having tenaciously followed this particular evidence via checks completed in the last few days." The two effects will get a new round of tests in May, when the two labs are scheduled to make velocity measurements with short-pulsed beams designed to give readings much more precise than scientists have achieved so far.
Athanasia Nikolaou

Nature Paper: Rivers and streams release more CO2 than previously believed - 6 views

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    Another underestimated source of CO2, are turbulent waters. "The stronger the turbulences at the water's surface, the more CO2 is released into the atmosphere. The combination of maps and data revealed that, while the CO2 emissions from lakes and reservoirs are lower than assumed, those from rivers and streams are three times as high as previously believed." Alltogether the emitted CO2 equates to roughly one-fifth of the emissions caused by humans. Yet more stuff to model...
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    This could also be a mechanism to counter human CO2 emission ... the more we emit, the less turbulent rivers and stream, the less CO2 is emitted there ... makes sense?
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    I guess there is a natural equilibrium there. Once the climate warms up enough for all rivers and streams to evaporate they will not contribute CO2 anymore - which stops their contribution to global warming. So the problem is also the solution (as always).
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    "The source of inland water CO2 is still not known with certainty and new studies are needed to research the mechanisms controlling CO2 evasion globally." It is another source of CO2 this one, and the turbulence in the rivers is independent of our emissions in CO2 and just facilitates the process of releasing CO2 waters. Dario, if I understood correct you have in mind a finite quantity of CO2 that the atmosphere can accomodate, and to my knowledge this does not happen, so I cannot find a relevant feedback there. Johannes, H2O is a powerful greenhouse gas :-)
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    Nasia I think you did not get my point (a joke, really, that Johannes continued) .... by emitting more CO2 we warm up the planet thus drying up rivers and lakes which will, in turn emit less CO2 :) No finite quantity of CO2 in the atmosphere is needed to close this loop ... ... as for the H2O it could just go into non turbulent waters rather than staying into the atmosphere ...
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    Really awkward joke explanation: I got the joke of Johannes, but maybe you did not get mine: by warming up the planet to get rid of the rivers and their problems, the water of the rivers will be accomodated in the atmosphere, therefore, the greenhouse gas of water.
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    from my previous post: "... as for the H2O it could just go into non turbulent waters rather than staying into the atmosphere ..."
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    I guess the emphasis is on "could"... ;-) Also, everybody knows that rain is cold - so more water in the atmosphere makes the climate colder.
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    do you have the nature paper also? looks like very nice, meticulous typically german research lasting over 10 years with painstakingly many researchers from all over the world involved .... and while important the total is still only 20% of human emissions ... so a variation in it does not seem to change the overall picture
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    here is the nature paper : http://www.nature.com/nature/journal/v503/n7476/full/nature12760.html I appreciate Johannes' and Dario's jokes, since climate is the common ground that all of us can have an opinion, taking honours from experiencing weather. But, the same as if I am trying to make jokes for material science, or A.I. I take a high risk of failing(!) :-S Water is a greenhouse gas, rain rather releases latent heat to the environment in order to be formed, Johannes, nice trolling effort ;-) Between this and the next jokes to come, I would stop to take a look here, provided you have 10 minutes: how/where rain forms http://www.scribd.com/doc/58033704/Tephigrams-for-Dummies
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    omg
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    Nasia, I thought about your statement carefully - and I cannot agree with you. Water is not a greenhouse gas. It is instead a liquid. Also, I can't believe you keep feeding the troll! :-P But on a more topical note: I think it is an over-simplification to call water a greenhouse gas - water is one of the most important mechanisms in the way Earth handles heat input from the sun. The latent heat that you mention actually cools Earth: solar energy that would otherwise heat Earth's surface is ABSORBED as latent heat by water which consequently evaporates - the same water condenses into rain drops at high altitudes and releases this stored heat. In effect the water cycle is a mechanism of heat transport from low altitude to high altitude where the chance of infrared radiation escaping into space is much higher due to the much thinner layer of atmosphere above (including the smaller abundance of greenhouse gasses). Also, as I know you are well aware, the cloud cover that results from water condensation in the troposphere dramatically increases albedo which has a cooling effect on climate. Furthermore the heat capacity of wet air ("humid heat") is much larger than that of dry air - so any advective heat transfer due to air currents is more efficient in wet air - transporting heat from warm areas to a natural heat sink e.g. polar regions. Of course there are also climate heating effects of water like the absorption of IR radiation. But I stand by my statement (as defended in the above) that rain cools the atmosphere. Oh and also some nice reading material on the complexities related to climate feedback due to sea surface temperature: http://journals.ametsoc.org/doi/abs/10.1175/1520-0442(1993)006%3C2049%3ALSEOTR%3E2.0.CO%3B2
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    I enjoy trolling conversations when there is a gain for both sides at the end :-) . I had to check upon some of the facts in order to explain my self properly. The IPCC report states the greenhouse gases here, and water vapour is included: http://www.ipcc.ch/publications_and_data/ar4/wg1/en/faq-2-1.html Honestly, I read only the abstract of the article you posted, which is a very interesting hypothesis on the mechanism of regulating sea surface temperature, but it is very localized to the tropics (vivid convection, storms) a region of which I have very little expertise, and is difficult to study because it has non-hydrostatic dynamics. The only thing I can comment there is that the authors define constant relative humidity for the bottom layer, supplied by the oceanic surface, which limits the implementation of the concept on other earth regions. Also, we may confuse during the conversation the greenhouse gas with the Radiative Forcing of each greenhouse gas: I see your point of the latent heat trapped in the water vapour, and I agree, but the effect of the water is that it traps even as latent heat an amount of LR that would otherwise escape back to space. That is the greenhouse gas identity and an image to see the absorption bands in the atmosphere and how important the water is, without vain authority-based arguments that miss the explanation in the end: http://www.google.nl/imgres?imgurl=http://www.solarchords.com/uploaded/82/87-33833-450015_44absorbspec.gif&imgrefurl=http://www.solarchords.com/agw-science/4/greenhouse--1-radiation/33784/&h=468&w=458&sz=28&tbnid=x2NtfKh5OPM7lM:&tbnh=98&tbnw=96&zoom=1&usg=__KldteWbV19nVPbbsC4jsOgzCK6E=&docid=cMRZ9f22jbtYPM&sa=X&ei=SwynUq2TMqiS0QXVq4C4Aw&ved=0CDkQ9QEwAw
LeopoldS

CREAX - Function Database - 0 views

shared by LeopoldS on 24 Jun 09 - Cached
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    Functional classification of knowledge is a very effective way of stripping away boundaries between different industries and scientific disciplines. The function database provides descriptions, examples and animations for all known effects that can produce a function.
ESA ACT

Rendering for an Interactive 360 Degree Light Field Display - 0 views

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    Intrinsic 3-d effect are enabling for effective virtual reality systems......
LeopoldS

Prepare and transmit electronic text - American Institute of Physics - 2 views

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    new revTex version available ... what do they mean by this? how do they use XML and latex to XML? would this also be an option for acta futura? "While we appreciate the benefits to authors of preparing manuscripts in TeX, especially for math-intensive manuscripts, it is neither a cost-effective composition tool (for the volume of pages AIP currently produces) nor is it a format that can be used effectively for online publishing."
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    Dunno really, they may have some in-house process that converts LaTeX to XML for some reason. Probably they are using some subset of SGML, the standard generalized markup language from which both HTML and XML derive. Don't think is really relevant for Acta Futura, and the rest of the world seems to get along with TeX just fine...
jcunha

Experimental evidence for new Flexo-electric nanomaterial - 1 views

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    A new experiment proved the existence of a new effect in nanomaterials: flexo-electric effect. The material has built-in mechanical tension that changes shape when you apply electrical voltage, or that generates electricity if you change its shape and was theorized some decades ago. Now, SrTiO3 allowed to observe this new effect, being comparable with piezoelectric effect.
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    My old twente university group! :)
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    Isn't muscle wire quite old technology though?
johannessimon81

Exotic Quantum Effects Could Follow from Compound Now Confirmed to Conduct Only at Surface - 1 views

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    Samarium hexaboride seems to be a topological insulator as a bulk material. It conducts electricity only at its surface, i.e., in a 2D layer (like graphene). This might allow all kinds of exotic (quantum) effects...
santecarloni

How Likely Is a Runaway Greenhouse Effect on Earth? - Technology Review - 1 views

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    Sometime in the last few billion years, disaster struck one of Earth's nearest neighbours. Planetary geologists think there is good evidence that Venus was the victim of a runaway greenhouse effect which turned the planet into the boiling hell we see today. A similar catastrophe is almost certain to strike Earth in about 2 billion years, as the Sun increases in luminosity.
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    the actual paper: http://arxiv.org/abs/1201.1593 just wondering if their conclusion that the long term solution is to change the orbit of Earth is really the ultimate wisdom ...
santecarloni

How To Build A Speech Jamming Gun - Technology Review - 1 views

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    he drone of speakers who won't stop is an inevitable experience at conferences, meetings, cinemas and public libraries.  Today, Kazutaka Kurihara at the National Institute of Advanced Industrial Science and Technology in Tskuba and Koji Tsukada at Ochanomizu University, both in Japan, present a radical solution: a speech jamming device that forces recalcitrant speakers into submission. 
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    ...must...not...make...the...obvious...ACT...meeting...joke...
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    Unfortunately it won't work when it is most needed .... Read this: "Their tests also identify some curious phenomena. They say the gun is more effective when the delay varies in time and more effective against speech that involves reading aloud than against spontaneous monologue. Sadly, they report that it has no effect on meaningless sound sequences such as "aaaaarghhh".
Isabelle Dicaire

Measuring height by connecting clocks - 2 views

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    They were able to compare the ticking rates of two optical clocks separated by 2000 km, with the objective of computing sea level based on the effect gravity has on the clock ticking rate. They did the experiment using glass optical fibers, but I wonder if we could one day do the same from orbit, to measure the gravitational field around Earth.
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    isn't this is effectively what pacome has been doing with his time for the last few years? e.g. http://arxiv.org/pdf/1308.6766v1.pdf also mentioning the ACES experiment
LeopoldS

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. (...)"
ESA ACT

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."
Marcus Maertens

[1806.03856] Computing the minimal crew for a multi-generational space travel towards P... - 5 views

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    How many people to we actually need put on that ship?
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    We should invite these people to the AF special issue
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    sounds really interesting. their simulations don't account for biological issues (mutation, migration, selection, drift, founder effect) though, so the numbers are very low. this paper (https://ac.els-cdn.com/S0094576513004669/1-s2.0-S0094576513004669-main.pdf?_tid=6bec2a5c-f05f-4024-b4de-af78ab06fd42&acdnat=1531827379_d4f0be1b193873890d6e5b4574e82f2e) takes those effects and their implications on genetic composition of populations into account, but the numbers are enormous. do you have an idea why they (marin and beluffi) wouldn't put those effects into the simulations?
anonymous

Impact: Earth! - 4 views

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    A website that lets you simulate the effects of a specified asteroid impact on earth.
santecarloni

Virtual phonons get real - physicsworld.com - 0 views

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    An acoustic analogue of the dynamical Casimir effect (DCE) has been demonstrated for the first time.
dejanpetkow

Holo-Deck 1.0 - YouTube - 3 views

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    Another Star Trek technology :) Might have an positive psychological effect if astronauts on long term missions could virtually escape their confinement - walking through a labyrinth with the blue sky above them. Ok, ISS does not provide enough space, but on Moon or Mars...
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    Is there not a risk that while walking in circles this way the cable I keep dragging behind will eventually strangle me?
Daniel Hennes

CubeSat Ambipolar Thruster - 2 views

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    "Cast your name into deep space in style!"
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    Interesting approach, but with 99.9% probability they will miserably fail (at least in terms of their time schedule) simply because the technology is untested. I haven't read the refs (which miss by the way important works of E. Ahedo et al. on magnetic nozzle acceleration by ambipolar effects), but 1. using water means that you produce oxygen radicals which will erode chamber walls (ionisation efficiency is not 100% and experimental tests haven't been performed yet). 2. Electronic excitation (and radiation), rotational excitation, vibrational excitation, and dissociation are all processes which consume energy and reduce ionisation efficiency drastically. 3. It is a miniaturised Helicon thruster. Theoretical analysis probably does not consider near field effects. Far field models are probably not applicable due to the size of the thruster. I expect some surprises during thruster testing. In any case - good luck!
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    Apparently, there is only one qualification constraint regarding CubeSat propulsion which is related to volatile propellant. Since they use water as propellant and are also the owner of the CubeSat it is actually up to them how they qualify their thruster. Given that it is also possible to qualify the thruster within 18 months - since they define what "qualification" means.
jaihobah

Breakthrough method means CRISPR just got a lot more relevant to human health - 0 views

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    "scientists at Harvard University say they've modified the CRISPR method so it can be used to effectively reverse mutations involving changes in one letter of the genetic code. That's important because two-thirds of genetic illness in humans involve mutations where there's a change in a single letter."
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    "Efficient introduction of specific homozygous and heterozygous mutations using CRISPR/Cas9" http://www.nature.com/nature/journal/vaop/ncurrent/full/nature17664.html?WT.ec_id=NATURE-20160428&spMailingID=51249830&spUserID=MTEzODM0NjYzMzgS1&spJobID=903461217&spReportId=OTAzNDYxMjE3S0 As posted here previously, the number and importance of CRISPR is growing steadily, but still plenty of work to make it a reliable tool. Maybe, next work for the Molecular Engineering RF?
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