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santecarloni

'Superbubble' generates cosmic rays - physicsworld.com - 0 views

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    A vast bubble of hot, rarefied gas has been revealed as a source of cosmic rays - the mysterious particles that batter the Earth continuously. The observation of the so-called superbubble, measuring more than 100 light-years across, was made using gamma rays collected by NASA's Fermi satellite and sheds light on the origin of cosmic rays in regions of massive-star formation.
santecarloni

Laser gyroscope measures the Earth's 'wobble' - physicsworld.com - 2 views

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    An international team of researchers have developed a new type of gyroscope that is the first to measure the "wobble" in the rotational axis of the Earth from a ground-based laboratory. Astronomers normally track this wobble by continuously monitoring the position of distant objects, such as quasars. But this new method will provide a much simpler and cheaper alternative to these large-scale astronomical readings, the scientists claim.
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    is this of any use for spacecraft?
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    mmm it's like saying that you can replace satellite tracking by accelerometers on-board satellites... for Leo: you'd better put an atomic gyro on a spacecraft these laser gyro are huge !
LeopoldS

David Miranda, schedule 7 and the danger that all reporters now face | Alan Rusbridger ... - 0 views

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    During one of these meetings I asked directly whether the government would move to close down the Guardian's reporting through a legal route - by going to court to force the surrender of the material on which we were working. The official confirmed that, in the absence of handover or destruction, this was indeed the government's intention. Prior restraint, near impossible in the US, was now explicitly and imminently on the table in the UK. But my experience over WikiLeaks - the thumb drive and the first amendment - had already prepared me for this moment. I explained to the man from Whitehall about the nature of international collaborations and the way in which, these days, media organisations could take advantage of the most permissive legal environments. Bluntly, we did not have to do our reporting from London. Already most of the NSA stories were being reported and edited out of New York. And had it occurred to him that Greenwald lived in Brazil?

    The man was unmoved. And so one of the more bizarre moments in the Guardian's long history occurred - with two GCHQ security experts overseeing the destruction of hard drives in the Guardian's basement just to make sure there was nothing in the mangled bits of metal which could possibly be of any interest to passing Chinese agents. "We can call off the black helicopters," joked one as we swept up the remains of a MacBook Pro.

    Whitehall was satisfied, but it felt like a peculiarly pointless piece of symbolism that understood nothing about the digital age. We will continue to do patient, painstaking reporting on the Snowden documents, we just won't do it in London. The seizure of Miranda's laptop, phones, hard drives and camera will similarly have no effect on Greenwald's work.

    The state that is building such a formidable apparatus of surveillance will do its best to prevent journalists from reporting on it. Most journalists can see that. But I wonder how many have truly understood
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    Sarah Harrison is a lawyer that has been staying with Snowden in Hong Kong and Moscow. She is a UK citizen and her family is there. After the miranda case where the boyfriend of the reporter was detained at the airport, can Sarah return safely home? Will her family be pressured by the secret service? http://www.bbc.co.uk/news/world-latin-america-23759834
Dario Izzo

IPCC models getting mushy | Financial Post - 2 views

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    why am I not surprised .....
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    http://www.academia.edu/4210419/Can_climate_models_explain_the_recent_stagnation_in_global_warming A view of well-respected scientists on how to proceed from here, that was rejected from Nature. In any case, a long way to go...
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    unfortunately it's too early to cheer and burn more coal ... there is also a nice podcast associated to this paper from nature Recent global-warming hiatus tied to equatorial Pacific surface cooling Yu Kosaka & Shang-Ping Xie Nature 501, 403-407 (19 September 2013) doi:10.1038/nature12534 Received 18 June 2013 Accepted 08 August 2013 Published online 28 August 2013 Despite the continued increase in atmospheric greenhouse gas concentrations, the annual-mean global temperature has not risen in the twenty-first century1, 2, challenging the prevailing view that anthropogenic forcing causes climate warming. Various mechanisms have been proposed for this hiatus in global warming3, 4, 5, 6, but their relative importance has not been quantified, hampering observational estimates of climate sensitivity. Here we show that accounting for recent cooling in the eastern equatorial Pacific reconciles climate simulations and observations. We present a novel method of uncovering mechanisms for global temperature change by prescribing, in addition to radiative forcing, the observed history of sea surface temperature over the central to eastern tropical Pacific in a climate model. Although the surface temperature prescription is limited to only 8.2% of the global surface, our model reproduces the annual-mean global temperature remarkably well with correlation coefficient r = 0.97 for 1970-2012 (which includes the current hiatus and a period of accelerated global warming). Moreover, our simulation captures major seasonal and regional characteristics of the hiatus, including the intensified Walker circulation, the winter cooling in northwestern North America and the prolonged drought in the southern USA. Our results show that the current hiatus is part of natural climate variability, tied specifically to a La-Niña-like decadal cooling. Although similar decadal hiatus events may occur in the future, the multi-decadal warming trend is very likely to continue with greenhouse gas
LeopoldS

Testing Continues for Satellite Servicing Capabilities | NASA - 0 views

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    Engineers at NASA's Kennedy Space Center in Florida are partnering with counterparts at the agency's Goddard Space Flight Center in Maryland to develop systems to bring potential future robotic "service tow trucks" to orbiting spacecraft in need of aid
Dario Izzo

Optimal Control Probem in the CR3BP solved!!! - 7 views

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    This guy solved a problem many people are trying to solve!!! The optimal control problem for the three body problem (restricted, circular) can be solved using continuation of the secondary gravity parameter and some clever adaptation of the boundary conditions!! His presentation was an eye opener ... making the work of many pretty useless now :)
  • ...13 more comments...
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    Riemann hypothesis should be next... Which paper on the linked website is this exactly?
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    hmmm, last year at the AIAA conference in Toronto I presented a continuation approach to design a DRO (three-body problem). Nothing new here unfortunately. I know the work of Caillau, although interesting what is presented was solved 10 years ago by others. The interest of his work is not in the applications (CR3BP), but in the research of particular regularity conditions that unfortunately make the problem limited practically. Look also at the work of Mingotti, Russel, Topputo and other for the (C)RTBP. Smart-One inspired a bunch of researchers :)
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    Topputo and some of the others 'inspired' researchers you mention are actually here at the conference and they are all quite depressed :) Caillau really solves the problem: as a one single phase transfer, no tricks, no misconvergence, in general and using none of the usual cheats. What was produced so far by other were only local solutions valid for the particular case considered. In any case I will give him your paper, so that he knows he is working on already solved stuff :)
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    Answer to Marek: the paper you may look at is: Discrete and differential homotopy in circular restricted three-body control
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    Ah! with one single phase and a first order method then it is amazing (but it is still just the very particular CRTBP case). The trick is however the homotopy map he selected! Why this one? Any conjugate point? Did I misunderstood the title ? I solved in one phase with second order methods for the less restrictive problem RTBP or simply 3-body... but as a strict answer to your title the problem has been solved before. Nota: In "Russell, R. P., "Primer Vector Theory Applied to Global Low-Thrust Trade Studies," JGCD, Vol. 30, No. 2", he does solve the RTBP with a first order method in one phase.
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    I think what is interesting is not what he solved, but how he solved the problem. But, are means more important than end ... I dunno
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    I also loved his method, and it looked to me that is far more general than the CRTBP. As for the title of this post, OK maybe it is an exageration as it suggests that no solution was ever given before, on the other end, as Marek would say "come on guys!!!!!"
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    The generality has to be checked. Don't you think his choice of mapping is too specific? he doesn't really demonstrate it works better than other. In addition, the minimum time choice make the problem very regular (i guess you've experienced that solving min time is much easier than mass max, optimality-wise). There is still a long way before maximum mass+RTBP, Topputo et al should be re-assured :p Did you give him my paper, he may find it interesting since I mention the homotopy on mu but for max mass:)
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    Joris, that is the point I was excited abut, at the conference HE DID present solutions to the maximum mass problem!! One phase, from LEO to an orbit around the moon .. amazing :) You will find his presentation on line.... (according to the organizers) I gave him the reference to you paper anyway, but no pdf though as you did not upload it on our web pages and I could not find it in the web. So I gave him some bibliography I had with be from the russians, and from Russell, Petropoulos and Howell, As far as I know these are the only ones that can hope to compete with this guy!!
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    for info only, my phd, in one phase: http://pdf.aiaa.org/preview/CDReadyMAST08_1856/PV2008_7363.pdf I prefered Mars than the dead rock Moon though!
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    If you send me the pdf I can give it to the guy .. the link you gave contains only the first page ... (I have no access till monday to the AIAA thingy)
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    this is why I like this Diigo thingy so much more than delicious ...
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    What do you mean by this comment, Leopold? ;-) Jokes apart: I am following the Diigo thingy with Google Reader (rss). Obviously, I am getting the new postings. But if someone later on adds a comment to a post, then I can miss it, because the rss doesn't get updated. Not that it's a big problem, but do you guys have a better solution for this? How are you following these comments? (I know that if you have commented an entry, then you get the later updates in email.) (For example, in google reader I can see only the first 5 comments in this entry.)
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    I like when there are discussions evolving around entries
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    and on your problem with the RSS Tamas: its the same for me, you get the comments only for entries that you have posted or that you have commented on ...
Tobias Seidl

German paper chase to end : Nature News - 5 views

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    No more endless publication lists needed for grant applications. Hopefully a trend that continues.
Francesco Biscani

Open Source Software Meets Do-It-Yourself Biology - 1 views

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    "As the shift to open source software continues, computational biology will become even more accessible, and even more powerful, while intellectual property and other bureaucracies continue to hobble traditional forms of research." Spot on, I'm very glad to see this happening :)
ESA ACT

Why Sleep? | Physical Review Focus - 0 views

shared by ESA ACT on 24 Apr 09 - Cached
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    A study in the January Physical Review E suggests that a sleep-wake cycle, allowing the brain to focus on one task at a time, may be the most efficient way to operate. The researcher shows mathematically that processing a continuously changing resource--s
ESA ACT

nativeclient - Google Code - 0 views

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    After Chrome, Google continues to branch out into other territories. This is somewhere between Java and Flash and others. It seems to me (Kev) that this could be quite important (if it doesnt die like Lively did) for online apps. Can anyone check it out i
ESA ACT

Obama-Biden Transition Project: Space Solar Power (SSP) -- A Solution for Energy Indepe... - 0 views

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    in addition, the fact that Gates remains Defence Secretary might give some continuity to the Pentagon activities, -LS
Marcus Maertens

Mars likely to have enough oxygen to support life - 2 views

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    Brine deposits below the surface should in theory be able to hold enough oxygen to support microbial aerobic lifeforms. The quest continues.
johannessimon81

Creating Indestructible Self-Healing Chips - 0 views

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    Chips are able to compensate for very large damage and continue working at high performance
Ma Ru

Netherlands in Proverbs - 3 views

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    Continuing the museum theme... today's Wikipedia Picture of the Day. This might be *the* ultimate test of the knowledge of Dutch... can you name any of them? On the more ACT-like note: I wonder how the contemporary version would look like? P.S. Yes, the proverbs are listed on Wikipedia and yes, lots of them involve herring.
Marcus Maertens

Government Lab Reveals It Has Operated Quantum Internet For Over Two Years | MIT Techno... - 0 views

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    They already surfing in the quantum web...
Luke O'Connor

Google gets driverless licence - 1 views

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    Driverless cars will soon be a reality on the roads of Nevada after the state approved America's first self-driven vehicle licence. The first to hit the highway will be a Toyota Prius modified by search firm Google, which is leading the way in driverless car technology.
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    makes me think of the trend years ago to promote car-pooling and avoid 1 driver per car. The trend continues!
johannessimon81

3D-solar cells much more efficient - 1 views

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    3-dimensional silicon solar cell produces at least 250% of the power of a basic silicon solar cell.
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    Any idea of the technology behind ... Sounds too much advertisement what is in the article " Now, our near term objective is to continue to improve the fabrication process and the power output, as we optimize the cost of manufacturing. We believe that the result will be a 50% reduction in the cost of solar electricity. Perhaps the installed system cost savings will be even greater"
Lionel Jacques

String-theory calculations describe 'birth of the universe' - 0 views

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    Researchers in Japan have developed what may be the first string-theory model with a natural mechanism for explaining why our universe would seem to exist in three spatial dimensions if it actually has six more. According to their model, only three of the nine dimensions started to grow at the beginning of the universe, accounting both for the universe's continuing expansion and for its apparently three-dimensional nature. ... The team has yet to prove that the Standard Model of particle physics will show up in its model,...
Luís F. Simões

Poison Attacks Against Machine Learning - Slashdot - 1 views

  • Support Vector Machines (SVMs) are fairly simple but powerful machine learning systems. They learn from data and are usually trained before being deployed.
  • In many cases they need to continue to learn as they do the job and this raised the possibility of feeding it with data that causes it to make bad decisions. Three researchers have recently demonstrated how to do this with the minimum poisoned data to maximum effect. What they discovered is that their method was capable of having a surprisingly large impact on the performance of the SVMs tested. They also point out that it could be possible to direct the induced errors so as to produce particular types of error.
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    http://arxiv.org/abs/1206.6389v2 for Guido; an interesting example of "takeover" research
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