Group items tagged

Earth's irregular natural satellites (NES) that are temporarily captured from the near-Earth-object (NEO) population. --> Possibly interesting for NEO exploration? http://arxiv.org/abs/1112.3781

How early could we detect these coming?

"When a control laser is fired at the crystal, a complex quantum-level reaction turns it the opaque crystal transparent. A second light source is beamed into the crystal before the control laser is shut off, returning the crystal to its opaque state. This leaves the light trapped inside the crystal, and the opacity of the crystal keeps the light trapped inside from bouncing around, effectively bringing light to a full stop." is the simple explanation, but I am not sure how this is actually possible with the current laws of physics

There are two ways to make slow light: material slow light and structural slow light, where you either change the material or the structural properties of your system. Here they used EIT to make material slow light, by inducing transparency inside an otherwise opaque material. As you change the absorption properties of a material you also change its dispersion properties, the so-called Kramers-Kronig relations. A rapid positive change in the dispersion properties of a material will give rise to slow light. To effectively stop light they switched off the control beam, bringing back the opaque state. Another control beam is then used to retrieve the probe pulse that was 'frozen' inside the medium. Light will be halted according to the population lifetime on the energy level (~ 100s). They used an evolutionary algorithm to find an optimal pulse preparation sequence to reach close to the maximum possible storage duration of 100s. Interesting paper!

So it is not real storage then in a sense, as you are stimulating an excitation population which retains the phase information of your original pulse? Still it is amazing that they could store this up to 100s and retrieve it with a probe pulse, but light has never been halted.

Elon Musk is moving forward with space based internet service...

Facebook announced they are ready to test of of their High Altitude Platform element, a drone of the size of a Boeing 737. See the new here http://phys.org/news/2015-07-facebook-ready-giant-drone-internet.html?utm_source=nwletter&utm_medium=email&utm_content=ctgr-item&utm_campaign=daily-nwletter. It seemed interesting for me that they are developing also a reliable optical communication between this element and scattered ground stations.

Nice link, that thing is huge and I would love to see a drone that size fly. Also, Facebook's Aerospace Team? :)

Following up on our coffee-time discussion, here's an Evolutionary Algorithm where you are the fitness function, and evolution is guided by your subjective artistic sense. Start from scratch, or pick an existing image in the database, and start evolving. At every generation, you are presented with the individuals/images in the population. Pick the ones you like. Those will be the parents from which the next generation will be bred. Repeat, repeat... where do you get to? If you want to learn more about the science behind this, check the tutorial below by Kenneth Stanley, who is also this site's supervisor: http://dx.doi.org/10.1145/1830761.1830920

Tokyo has a very large population and one of the smallest crime rates in the world, in fact Tokyo is known to be the safest big city in the world (w.r.t. crime). It is hard to believe that the crime rate in L.A. is in the same order of magnitude.

Asimov's Foundation meets ACT's Tipping Point Prediction?

still, some interesting thoughts in there ... "Then you have the 50-year cycles of violence. Turchin describes these as the building up and then the release of pressure. Each time, social inequality creeps up over the decades, then reaches a breaking point. Reforms are made, but over time, those reforms are reversed, leading back to a state of increasing social inequality. The graph above shows how regular these spikes are - though there's one missing in the early 19th century, which Turchin attributes to the relative prosperity that characterized the time. He also notes that the severity of the spikes can vary depending on how governments respond to the problem. Turchin says that the United States was in a pre-revolutionary state in the 1910s, but there was a steep drop-off in violence after the 1920s because of the progressive era. The governing class made decisions to reign in corporations and allowed workers to air grievances. These policies reduced the pressure, he says, and prevented revolution. The United Kingdom was also able to avoid revolution through reforms in the 19th century, according to Turchin. But the most common way for these things to resolve themselves is through violence. Turchin takes pains to emphasize that the cycles are not the result of iron-clad rules of history, but of feedback loops - just like in ecology. "In a predator-prey cycle, such as mice and weasels or hares and lynx, the reason why populations go through periodic booms and busts has nothing to do with any external clocks," he writes. "As mice become abundant, weasels breed like crazy and multiply. Then they eat down most of the mice and starve to death themselves, at which point the few surviving mice begin breeding like crazy and the cycle repeats." There are competing theories as well. A group of researchers at the New England Complex Systems Institute - who practice a discipline called econophysics - have built their own model of political violence and

It's not the scientific activity described in the article that is uninteresting, on the contrary! But the way it is described is just a bad joke. Once again the results itself are seemingly not sexy enough and thus something is sold as the big revolution, though it's just the application of the oldest scientific principles in a slightly different way than used before.

remember the discussion I tried to trigger in the team a few weeks ago ...

I love the linked article provided by Johannes! It expresses very elegantly why I still fail to understand even extremely smart and busy people in my view apparently waiting their time in playing computer games - but I recognise that there is something in games that we apparently need / gives us something we cherish .... "In fact, half a million players so far have registered to help destroy the 64 billion tiny blocks that compose that one gigantic cube, all working in tandem toward a singular goal: discovering the secret that Curiosity's creator says awaits one lucky player inside. That's right: After millions of man-hours of work, only one player will ever see the center of the cube. Curiosity is the first release from 22Cans, an independent game studio founded earlier this year by Peter Molyneux, a longtime game designer known for ambitious projects like Populous, Black & White and Fable. Players can carve important messages (or shameless self-promotion) onto the face of the cube as they whittle it to nothing. Image: Wired Molyneux is equally famous for his tendency to overpromise and under-deliver on his games. In 2008, he said that his upcoming game would be "such a significant scientific achievement that it will be on the cover of Wired." That game turned out to be Milo & Kate, a Kinect tech demo that went nowhere and was canceled. Following this, Molyneux left Microsoft to go indie and form 22Cans. Not held back by the past, the Molyneux hype train is going full speed ahead with Curiosity, which the studio grandiosely promises will be merely the first of 22 similar "experiments." Somehow, it is wildly popular. The biggest challenge facing players of Curiosity isn't how to blast through the 2,000 layers of the cube, but rather successfully connecting to 22Cans' servers. So many players are attempting to log in that the server cannot handle it. Some players go for utter efficiency, tapping rapidly to rack up combo multipliers and get more

why are video games so much different than collecting stamps or spotting birds or planes ? One could say they are all just hobbies

completely new cosmic phenomenon?

The final goodbye of a massive star collapsing to a black hole? http://www.sciencedaily.com/releases/2013/07/130705101626.htm?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+sciencedaily+%28ScienceDaily%3A+Latest+Science+News%29

Might be a useful reference for PyGMO-related works.

My daily read, a collection of blog posts related mostly to energy by UCSD prof Tom Murphy. Especially his experiments into home energy storage and his "do the math" attitude towards renewables are insightful and if not, then sometimes just plain funny.

nice one: http://physics.ucsd.edu/do-the-math/2013/09/the-real-population-problem/#more-1414

I wonder how much energy you can extract from the ocean in a responsible way... Mixing up different thermal layers would probably a quite an influence on ecology.

The last available assessment report on the ecological impact seems to date from 1981 which would need to be brought up to current standards. On the other hand, this system could have a positive influence on fish population as deep cold water brings nutrients to the surface. The cold water could also be used to lower sea surface temperatures and affect hurricane genesis!

fertility world_population

Perhaps Mister Burkeman should have read this first...

Reminds me something... :)

I check diigo for the first time since I left and my spirit is still there yeah !

the 10th is interesting, connected with our crowdsourcing experiments with the spacegame

Dario - perhaps worth giving a look to be up-to-date... There's even an article "Improving Classical and Decentralized Differential Evolution with New Mutation Operator and Population Topologies". They quote our CEC paper, but not the ParCo.

Isn't it a bit a paper-killing quote?

:) It's in the context of a review of the work that's been done about DE with island model in general, they don't evaluate. Pity they didn't refer to the ParCo article on topologies, as it was a bit more extensive and more focused on the method (as they do in the article) rather than on the problem (as was our CEC paper, if I recall well).

dark matter :-) ?? could there be loads of them?

here's something we didn't consider yesterday in the meeting on extra-solar planets!

this is because you did not read the nature paper I have posted (see post a few lines below ...)