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Comment: Old news, probably not dark matter (Score 5, Informative) 66

by disputationist (#48585291) Attached to: Possible Dark Matter Signal Spotted
This is really old news (at least in the particle physics cycle) and over a 100 papers have been written about this already. This is one of many papers that points out serious problems with a dark matter interpretation for this signal http://arxiv.org/abs/1408.1699 and here's a less technical blog post discussing the issues http://resonaances.blogspot.co... . I'm sick of pop-sci websites peddling stuff that particle physicists have already moved on from as the "latest exciting discovery"

+ - LUX experiment rules out low mass dark matter

Submitted by thegreatemu
thegreatemu (1457577) writes "The LUX collaboration today released the first results using their huge liquid xenon detector to search for dark matter interactions in a live webcast from South Dakota's Sanford Lab. (Here's a copy of the talk and the corresponding paper (warning: PDFs)).
Their conclusion: they see no positive evidence for any kind of dark matter. Moreover, they have pretty conclusively (by a factor of 20!) ruled out conventional dark matter as a source of the low energy signals seen by many of their dark matter competitors (CDMS, CoGeNT, CRESST, and DAMA)."

+ - Fitness bracelet with blood spectrometer->

Submitted by disputationist
disputationist (1324927) writes "Airo Heath claims that their wristband AIRO will be able to measure calories and nutritional content of food ingest using an embedded spectrometer : "As your body breaks the food down, the sensor can detect the amount of light that passes through the blood based on green, red and infrared patterns." The press release does not say how precise the device is, but in a comment the CEO says it "compares favorably to nutrition labels for about 8/10 of the foods we’ve tested". Does this seem plausible for a $150 wristband?"
Link to Original Source

Comment: Higgs has been discovered!! (Score 2) 99

by disputationist (#38319570) Attached to: LHC To Narrow Search For Higgs Boson
Both CMS and ATLAS are seeing bumps in certain Higgs channels around 125 GeV. While the bumps aren't big enough to be press-release worthy (2-3 sigma), a lot of particle physicists think that this is it. There will be an announcement on Dec 13th, and from now on it'll just be a matter of waiting till the bumps are 5 sigma and we can say for sure sure.

Comment: Re:I also noticed a link (Score 2, Insightful) 289

by disputationist (#29213223) Attached to: Obesity May Accelerate Brain Aging

A study, with so much bluster, and they studied just 94 people. Chuck a couple of zeros on that, then perhaps you have the makings of a worthwhile study and not just an anecdote.

Ugh. Not another math illiterate person complaining about the sample size. For the last time, your intuitive notions of statistics are worthless. The gamer study had a lot of people repeating this stupid objection too.

Comment: Re:Correction : Average of 552 adults 19-90 (Score 1) 439

by disputationist (#29130337) Attached to: Average Gamer Is 35, Fat and Bummed

I am increasingly sick of these kinds of studies that use a sample pool so small as to be statistically irrelevant.

No, it's just that your intuitive ideas of what kind of sample size is statistically relevant are invalid. I am sick of how many people keep saying this even though it was addressed in an earlier post http://games.slashdot.org/comments.pl?sid=1341207&cid=29120539 .

Also, the complaints about the sample size being restricted to Seattle are probably unwarranted. The sample size is large enough to provide a 95% confidence level for a reasonably small interval, and it would be highly unusual for such a general result that's true in Seattle to be significantly different for other cities.

It would imply that there was some confounding variable that's exclusive to Seattle that modifies the characteristics of gamers, which is an absurd assumption, and the only reason you would think so without other evidence is if you just didn't like the results of the study.

Comment: Re:Yeah... (Score 1) 348

by disputationist (#28227629) Attached to: String Theory Predicts Behavior of Superfluids
When people say evolution they don't just mean descent with modification, they mean the hypothesis that descent with modification (and other little things perhaps) is responsible for all the various species, and that this is how they descended from a common (and probably) single ancestor. It it this hypothesis that does not make (sufficiently) falsifiable predictions. Descent with variation is rather trivial and was known before and independent of Darwinian evolution. Anyone who breeds anything knows this.

Comment: Poster doesn't understand TFA (Score 5, Informative) 348

by disputationist (#28221941) Attached to: String Theory Predicts Behavior of Superfluids
The Maldacena duality can't be used to 'make predictions' with a string theory, its just a correspondence between a string theory and a conformal field theory. It's useful because sometimes calculations which are hard in a CFT can be made in the corresponding string theory which is sometimes easier (or vice versa). It cannot be used to support the physical validity of some string theory.

Comment: Re:Sounds neat, but I'm confused... (Score 1) 220

by disputationist (#26584635) Attached to: Scientists Teleport Information Between Ions a Meter Apart
Apparently the use of the term 'teleportation' is causing a lot of confusion. In QM, two particles that have identical states (quantum numbers) are considered indistinguishable; if they were switched, you wouldn't know. TFA describes a process that allows an entire state to be transferred instantaneously from one particle (or system) to another, and since in QM they are the same, the particle has been 'teleported'. There is nothing superluminal here, since before the state can be transferred you have to send some information across at kosher speeds.

Comment: Re:A question that maybe someone might answer... (Score 2, Informative) 220

by disputationist (#26584569) Attached to: Scientists Teleport Information Between Ions a Meter Apart
They know it was entangled because they prepared the state way. For example, if you have a spin zero particle that splits up into two particles, and you measure one as spin up, the other must be necessarily spin down, no matter how far away it is, because of the conservation of angular momentum. Or you can think of a neutral particle splitting into positive and negative ones. So I guess it is ultimately the consequence of some conservation law.

Comment: Re:Don't panic (Score 2, Interesting) 532

by disputationist (#26492813) Attached to: The Universe As Hologram

What we have is that classical mechanics is a particular approximation of general relativity, at one end of the scale, and of quantum mechanics, at the other.

Not quite, they describe different things, so you can put them on the same scale. Classical mechanics is a framework for describing the dynamics of a system once you specify the forces. QM is a different framework. But GR is a theory for describing a particular force, gravity.

A wonderful example iirc is the spinning top. In classical mechanics, the top cannot be solved exactly. But in general relativity, the top can be solved exactly in about one page

This doesn't make any sense IMO, unless you can come up with something to back it up. If you mean the precession of a top in the presence of gravity, then sure it can be solved analytically in classical mechanics, but the general two body problem has no analytical solution in GR, and I doubt the restriction to a top simplifies it enough to allow a closed form solution. But I can give you valid examples that suggest the opposite. In classical mechanics, the dynamics under a linear potential (constant force) is very simple: constant acceleration in one direction. But try solving that in quantum mechanics, and what you get are hideous Airy functions to describe the position of the particle.

The designer, then, still has the last laugh, until there is a TOE, if there ever is.

Not even then. I don't know what it means among laypeople, but for a physicist TOE means a quantum field theory that describes gravity, electroweak and strong force. I can guarantee that we will have such a theory in 100 years, and probably a lot less. I can also guarantee that this TOE will eventually be superseded by a more accurate theory.

Comment: Re:Don't panic (Score 3, Informative) 532

by disputationist (#26486121) Attached to: The Universe As Hologram

it is interesting to note that the universe is mainly built out of second order laws. This means that in many cases there are a small number of poles or zeros that can control macroscopic behaviour and often analytic solutions exist. This would be how a designer would do it.

Nope. It is just that scientists use simple models like harmonic oscillator for most systems, simply because they are easy to solve. That doesn't mean that the universe is 'built' from second order laws. The rest of your post is also similar misinterpretations of QM, optics etc

No one gets sick on Wednesdays.