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Comment: Heisenberg uncertainty (Score 1) 312

by xPsi (#45971511) Attached to: Why Standard Deviation Should Be Retired From Scientific Use
The celebrated Heisenberg uncertainty principle in quantum theory is based on statistical statements about the coupled standard deviations of position and momentum measurements (for example), not the mean deviation. The mean deviations are assumed to be zero since the means of the position and momentum distributions are exactly known for theoretical work. What matters are the fluctuations about the mean. In fairness, Taleb does allow physicists to keep using STD. But, quantum mechanics aside, it seems characterizing fluctuations about the mean, rather than fluctuations of the mean, is often an important measure depending on the nature of the investigation. Retiring the standard deviation seems a bit hasty.

Comment: Re:Electricity Pointy (Score 1) 828

by xPsi (#28035051) Attached to: I'll keep my castle secure primarily with ...
We should make the distinction between bound electrons (in a pointy stick) and free electrons (electricity). With pointy sticks, electrostatics is a player, but I'm guessing it is primarily the inertia of the massive nuclei and Pauli exclusion that are really doing damage (and breaking bonds in your skin). With electricity, it is electrodynamics, not electrostatics, which is the culprit. You may be thinking of electrostatic discharge, which isn't usually what people mean by "electricity", but, as most of us on /. know, can still be quite effective for security (and should be in the poll). Ok, sorry. Just mod me both "making crap up" and Pedantic 2+3i.
Education

+ - Daling with your advisor 1

Submitted by warrior_s
warrior_s (881715) writes "I think there are many graduate students as well as professors who read slashdot on regular basis. My question is about honesty of professors in academia.
What can a (new/junior) graduate student do when his advisor his passing on his work as the work of the more senior graduate student or a postdoc. I understand that senior graduate students are in need of good academic publications. But passing a junior student's work as someone else's work in unacceptable.
On the other hand, a junior student needs the help of faculty later on when he will be graduating. So, it is difficult to oppose this injustice. Specially in this economy, when just leaving the school is not an option for all. And changing the advisor (especially the one who is highly reputed in academia) is not seen as good thing in the department.
How can one deal with such advisors?"

Comment: NASA naming history (Score 1) 471

by xPsi (#27307383) Attached to: Colbert Wins Space Station Name Contest
NASA has a long history of naming missions and modules after rather arbitrary, but dignified sounding, things. For example, the arts (Apollo Theater, Orson Welles' Mercury theater company, etc.) as well as pseudo-scientific things like signs of the zodiac and crypto-geographic places and cryptozoological creatures. Not to mention South American countries featured in drug-oriented movies, science fiction space ships, and even abstract contestants on a game show. "Colbert" seems pretty consistent with this non sequitur trend.

Comment: Article summary (Score 1) 610

by xPsi (#27271317) Attached to: If We Have Free Will, Then So Do Electrons
"In a whimsical abuse of pedigree leading to much undeserved press, two guys who apparently understand neither philosophy nor quantum mechanics mathematically connect two of those fields' major questions in a non-peer reviewed arXiv article and simultaneously solve humanity's deepest ontological questions using a translucent haze of logic."

Comment: Bell's Inequality and entanglement (Score 4, Informative) 249

by xPsi (#26882685) Attached to: Physics Experiments To Inspire Undergraduates?

Here are a doublet of papers for an undergraduate laboratory demonstrating Bell's Inequality and and entangled photons. The whole apparatus (detailed in the second paper) is estimated to cost USD 15k circa 2002, so the optical elements have probably come down in price since then.

1. Entangled photons, nonlocality, and Bell inequalities in the undergraduate laboratory. [American Journal of Physics 70, 903 (2002)], Dietrich Dehlinger, MW Mitchell. http://arxiv.org/abs/quant-ph/0205171/

2. Entangled photon apparatus for the undergraduate laboratory. [American Journal of Physics 70, 898 (2002)], Dietrich Dehlinger, MW Mitchell. http://arxiv.org/abs/quant-ph/0205172/

Education

Physics Experiments To Inspire Undergraduates? 249

Posted by kdawson
from the describe-the-universe-and-give-two-examples dept.
PShardlow writes "I have recently been asked to propose two projects for a 1st year undergraduate teaching laboratory in the summer term this year. These are projects that a pair of students will spend 36 hours working on, and as such can be quite in-depth. A good project would include something they can build, something they can measure, and something they can calculate. Previous projects have included cloud chambers, a Jacobs ladder, a laser Doppler speed camera, laser sound detection, smoke rings, and physical random number generators. This is an opportunity to really inspire students into the joy that can be experimental physics — but it only works if we demonstrators propose interesting projects. So I ask the Slashdot community for suggestions of fascinating projects to do, things that are relevant to today's physics problems but could feasibly be completed by a pair of first-year undergraduates in 72 man hours."

Comment: Parlor games are memes too I guess (Score 1) 219

by xPsi (#26847245) Attached to: A Quantitative Study of How Memes Spread
I'm not sure why so much is being made of this '25 Random Things About Me' note on facebook. It is just a variation on an old parlor game that never really "came and went". Some people want to play, others don't. Yes, there are meme-y elements to virtually everything in a culture, but would an invitation to a kegger, superbowl party, LAN party, or a poker game be given such careful meme-y analysis? I'm not saying someone shouldn't analyze those things in this framework, but it seems this '25 Random Things About Me' note is being treated as a wild fad (some kind of canonical meme flash and burn) although it is really no different than some people at a large BBQ deciding to play poker while others play frisbee.

Comment: Re:Actually, the REAL victims IMHO (Score 2, Insightful) 219

by xPsi (#26833783) Attached to: A Quantitative Study of How Memes Spread
Be advised you are following the same meme cliche cycle by complaining about it. For every annoying decaying, witless in-joke past its glory days, there's someone who has a tired argument to remind us how annoying, witless, and cliche the in-joke really is. And similarly, there's someone like me who will boorishly complain about the complaining about it. And so on. Culture's one big recursive clicheplex. I don't think we can help it.

Comment: Re:Moon seems to have rotated in the past 400 year (Score 1) 82

by xPsi (#26681247) Attached to: The First Moon Map, and Not By Galileo
The paper rotation idea is interesting, but before assuming the moon itself rotated with respect to the earth, wouldn't it just be easier to assume he sketched it at a different time of night at, at a different latitude, and/or different season then used "towards the ground as I'm looking at it" as down in the sketch? The moon's apparent orientation wrt one's line of sight on earth depends on all those things. Perhaps knowing where he sketched it and at what time of year, one could then figure out what time of night he did his work.

Comment: Re:Clarifications (Score 1) 684

by xPsi (#26650075) Attached to: Miscalculation Invalidates LHC Safety Assurances
The probability of creating a voracious black hole at the LHC is about the same as creating a voracious 1972 Cadillac at the LHC. Indeed, it is about as probable as creating a voracious black hole next to your head right now out of the vacuum. Such doomsday ideas were utterly fabricated nonsense forged in the minds of highly fringe and misguided people. The core ideas of your paper are interesting, but your work is better applied to things that really matter, not the pseudoscience of doomsday at supercolliders. Using the doomsday mania to sex up your work is fear mongering and borders on the unethical. Getting HIV from a handshake, however insanely unlikely, is a billion times more probable than destroying the earth from collisions at the LHC, but you don't seem to have used this example. Why not? Perhaps because it would be unethical to spread such nonsense?

Physician: One upon whom we set our hopes when ill and our dogs when well. -- Ambrose Bierce

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