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# Slashdot: News for Nerds

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### MIT Wristband Is a Personal Climatizer

while the extra centripetal acceleration draws blood out closer to my fingertips.

I think you mean "centrifugal force". Note that a centripetal acceleration/force would be pulling your blood back inwards from your fingertips; you're looking for the equal and opposite force that is pulling the blood away.

Physics teachers who say that there is no such thing as centrifugal force are lying; it is every bit as real as gravity. It is a white lie, with the point of avoiding accelerating non-inertial reference frames. Such physics classes will show that centrifugal force is entirely explained by inertia in a reference frame undergoing centripetal acceleration. That's great.

Here's the problem: those same classes will regularly describe gravity as a force. The thing is, once you study general relativity you realize that gravity (and in particular the 9.8 m/s^2 acceleration you feel downward) has exactly the same explanation; space-time is curved by the mass of the Earth such that the surface of the Earth needs to accelerate upwards at 9.8 m/s^2 in order to remain "in place".

In other words, centrifugal force is entirely as real as gravity. If it is centrifugal force that makes your blood move out, don't be afraid to say it.

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Putting money in every paycheck is great and exactly the way to go, but isn't "dollar cost averaging". Dollar cost averaging is something else and entirely bogus.

Suppose you get \$120K. DCA advocates would tell you to invest, say, \$10K of it every month into your preferred asset allocation, rather than investing it all at once.

On the other hand, suppose your cat walks over your keyboard while you're logged into your brokerage and sells \$120K of stock. Do you invest it \$10K at a time or do you just reverse your transaction immediately? Hopefully it is obvious that you do the latter -- but this scenario is exactly equivalent to the first one.

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### Wireless Charging Start-Up Claims 30-Foot Radius

Just because something is done by 9th graders doesn't necessarily mean its flawed

The study isn't flawed because it was done by 9th graders. The study is flawed because it didn't control for a bunch of obvious things which would explain their result.

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### Ask Slashdot: Experiences Working At a High-Profile Game Studio?

The starting salary for a new college grad software engineer at the big tech companies in the SF Bay area is well over \$70K.

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### Senate To Vote On Internet Sales Tax (For Real This Time)

Re:This is a Constitutional tax (326 comments)

There are a number of fringe arguments that the sixteenth amendment, allowing an income tax, wasn't properly ratified.

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### Sony Launches Internet Service Offering Twice the Speed of Google Fiber

Re:And it's in Japan (268 comments)

If you're going to do a comparison like this you really need to count just the 23 special wards (14,485 per square kilometer). Tokyo the prefecture-equivalent "metropolis" includes a lot of areas which are essentially suburban sprawl west of Tokyo -- the Tama area. I don't think anyone would really consider, for example, Hachioji to be part of Tokyo the city, but it is a substantial fraction of Tokyo metropolis -- and if you're coming up with a number as low as 6,810 you're including it.

This is complicated by the fact there is no longer a government for Tokyo City, which is what used to be the 23 wards. The wards themselves are cities, somewhat comparable to a more independent and smaller form of NYC Boroughs. Conversely, Tokyo metropolis would be something like a separate State of New York City which includes both the Boroughs and Long Island and a couple of small islands in the Caribbean.

With that said, there's no ward of Tokyo which is as dense as Manhattan. mostly because there aren't a lot of tall buildings. The technology to build earthquake resistant skyscrapers is relatively new compared to a lot of the construction.

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### Tax Peculiarities Mean Facebook Paid No Net Taxes For 2012

You don't need to itemize to deduct student loan interest -- and conversely, the amount of student loan interest you deduct doesn't affect whether you'd itemize or not.

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### What's In Steve Ballmer's Inbox?

This is a standard strategy, which I've seen referred to as "turboing", which is particularly effective when standard channels fail. The key point is that, really, you're not trying to speak to senior management, you're trying to speak to the PA of someone in senior management.

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### Ask Slashdot: How Do I De-Dupe a System With 4.2 Million Files?

[citation needed]

A bug in your script is far more likely than a collision between two files in full 128 bit md5, barring a deliberate attack on md5 to create the collision.

about a year and a half ago
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### Travelling Salesman, Thriller Set In a World Where P=NP

Cracking a key is NP hard

No it isn't. It might not be in P, but it almost certainly is not NP hard. (Barring something like P=NP that would imply everything in P is NP hard)

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### Faster-Than-Fast Fourier Transform

This result was rather interesting for SODA because it wasn't an improvement in time complexity over the best known algorithm. There are asymptotically faster previously known algorithms for computing sparse FFTs, but they aren't actually faster than the current (extremely optimized) FFT implementations unless the output is extremely sparse.

This algorithm isn't quite as asymptotically fast but it has a much better constant factor, so it is more likely to be effective in practice on inputs which are not extremely large and/or outputs which are not extremely sparse.

more than 2 years ago
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### Faster-Than-Fast Fourier Transform

Posting a story about how a presentation will be given at SODA... about a day after SODA ended.

I actually went to this talk, which was scheduled for the first 8:30 AM timeslot as part of their evil conspiracy to get me to wake up early. The approach seemed remarkably straightforward, but I haven't gotten around to actually reading the paper yet -- I was too busy sightseeing around Kyoto.

more than 2 years ago
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### Siemens To Exit Nuclear Power Business

Re:Lessor of two evils... (400 comments)

will probably cause the premature deaths of several times that number

[citation needed]

(see: guardian.co.uk)

[lol]

more than 2 years ago
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### Teen Builds Nuclear Bomb Detector

Fusors are a standard neutron source, and they're fairly straightforward to build.

The idea that you could throw hydrogen ions at each other with enough energy to fuse is fairly obvious. It turns out that the obvious ways of doing so are orders of magnitude short of generating net power, but they do generate neutrons.

more than 2 years ago
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### No, We're Not Headed For a New Ice Age

Huh? Hereby nominated for stupidest /. comment ever.

You must be new here.

more than 2 years ago
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### Local Currencies To Replace Dollar For 5 Countries' Dealings

Re:you've been duped, it is 10% (519 comments)

Right, I've been duped into looking at the prices of things people actually buy, rather than their more expensive 1990 equivalents.

more than 2 years ago
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This is a standard definition of "regret" in an economics context.

more than 2 years ago
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### New Quantum Record: 14 Entangled Bits

No.

You can't use separated entangled qubits to send information faster than light. It doesn't work that way. There are a bunch of tricks and operations you can do, but none of them result in the other end being able to distinguish a change of state.

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### Senate Panel Backs Patent Overhaul Bill

Re:Who's law do you want to use? (243 comments)

This "harmoization" of US law with other countries is getting really old. We need to decide what we stand for and do it. Others can do as they wish. Why don't we just dump our whole government and put the states under some other one? Since we think adopting all their rules is a good idea... That is the stupidest reason I've ever seen for changing a law, and it gets used more often than a stupid idea should come up.

Eliminating arbitrary differences in regulation is stupid?

more than 3 years ago

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