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User: Physics+Dude

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  1. Not much of a jump at all... on Gary McKinnon Loses Extradition Appeal · · Score: 2, Insightful
    Maybe you've been living in a cave, but lately the US government has been holding people for years without even an actual charge against them, and have condoned and even defended use of torture of these "detainees".

    Also note that you can become one of these detainees, and have your constitutional rights as a citizen thrown out the door without anything more than an unsubstantiated accusation of terrorism.

    There are no checks and balances left in place to stop blatant abuse of this situation so that anyone can be at risk, and I suspect that you'd hear a lot more about this if there weren't "gag orders" and such to keep people quiet.

    With these kinds of things going on, just how far from a police state do you think we are? The current administration is trampling under foot the Constitution of the United States and people are happily pacified by their televisions and video consoles.

  2. Re:Ink on New Inkjet Technology 5 To 10 Times Faster · · Score: 2, Informative
    I have a Canon S9000 6-color inkjet and I've refilled the cartridges over and over for about two years with no problems using cheap Sam's Club refill kits. It's the cheapest printer I've used as far as ink costs go.

    I've tried to refill HP carts and it was a nightmare! I have either thrown or given away all of my HP inkjet printers. You should have a cron job to print a test page at least once a month though to keep your nozzles in use. For most of my printing I use B&W Laser though... very reliable, full duplex, high res. But when I need a nice 13"x19" photo quality, the Canon's great. ;)

  3. Re:Out of Nothing Nothing Comes on Stephen Hawking Says Universe Created from Nothing · · Score: 1
    A particle and it's anti-particle will pop out of nothing ...

    There is a widely taught and accepted tenet that you may have heard of called "Conservation of mass energy" which to my knowledge has never been found violated. Heck, they even call it a LAW! When pair production occurs it is an electromagnetic wave (photon) that the particles "pop out of" and the total energy of the prior photon and the subsequent particle and anti-particles' total relativistic energy are equal.

    I realize there are all kinds of ideas and wild theories about spontaneous particles appearing out of nothing, but I've never seen any hard **experimental** evidence to back that up. Please point me in the right direction if you have run across some. The articles that I've read that make wild and bizarre claims usually boil down to entirely theoretical physics which is inherently dangerous and by itself doesn't prove anything, or physicists with a limited scope of understanding misinterpreting their data, and their observed effects can usually be explained in a rational and simple manner. Ultimately most of these boil down to the author's interpretation which may or may not follow from the evidence.

    Anyway, that's just my take on things. Please stay tuned for my new book "Physics Refactored" which discusses these topics in much more detail. LOL ;)

  4. -1 redundant on California Joins Open Document Bandwagon · · Score: 1
    Error parsing slashdot post 18198372: User forgot to refresh article for before posting

    Oops!

  5. Please resubmit your comments... on California Joins Open Document Bandwagon · · Score: 1
    Error processing slashdot post 18194566: Line 2: tag "user" has no matching closing tag.

    ;-)

  6. Depends ... on Who Needs a Satellite Dish When You Have a Wok? · · Score: 4, Informative
    Actually the reflective efficiency depends on the power and frequency relative to the material conductivity and thickness. In order for a material to reflect an EM wave, it has to be capable of supporting the induced EM currents produce by the wave, and if I remember correctly, for maximum reflection the material has to be thicker than the skin depth at that frequency. If the thickness is much thinner than the skin depth then minimal reflection will occur and the EM wave may pass through the material or, if enough energy is absorbed by the material in the form of induced currents, the surface may be damaged.

    This is the effect you see with thin foils in a microwave oven, and has led to the extremely popular misconception that you can't put metal into a microwave. With a minimal bit of observation anyone will see that the entire microwave enclosure IS metal and reflects the microwaves just fine without significant absorption. The only problem is with thin foils which are incapable of efficiently reflecting the microwaves.

    I haven't calculated how efficiently tin-foil might reflect the high power radio waves mentioned here, but wouldn't put money either way without checking. (I haven't yet read the fine article, so I don't even know what power levels we're talking about).

  7. What's next? ... banning electric heat? on California Proposes to Ban Incandescent Lightbulbs · · Score: 1
    Some uses for incandescent lights are used as heat sources... for my pet iguana for example. Are they going to mandate I now use a gas heater for my iguana?

    I'm a fan of using the right tool for the job. When CFLs get cold, they can take a long time to get bright. I have one in my portch light and it takes quite a few minutes to get up to a reasonable brightness.

    Also, sometimes you just want different lighting for environmental effects... I want to be able to dim some lights low without them flickering and such and CLFs just don't seem to handle that.

  8. Re:Isn't this... on Diebold Security Foiled Again · · Score: 3, Interesting
    Isn't this the same key that will open mini-bars?



    Yes. From the article:

    " ... and beyond that, it could be opened with the same keys typically used with hotel minibars and jukeboxes."


  9. Re:Switching XP - Amiga on AmigaOS 4 · · Score: 1
    Okay so it's maybe stupid to be optimising a word processor in assembly or something along those lines, but ...

    A lot of the problem isn't just that things aren't being optimized in assembly, but in the design (or lack thereof) of the software. A lot of programmers just treat all memory/disk resources as a single infinite black box. If programmers would even make more of a conscious distinction between memory and filesystem we'd be half way there.

  10. Re:Can they drop the suit? on SCO Bankruptcy "Imminent, Inevitable" · · Score: 1
    Unless a "plausible" suit would be considered an asset ...

    I fail to see how what would be relevant in SCOs case. ;)

  11. Re:Call me a cynic if you like... on DARPA Challenge Prize Money Restored · · Score: 1

    Yes, one of the few areas where I think RFID *should* be used. :) You could embed RFID tags in the asphalt where passing cars could get all kinds of data... lane information, speed limits, etc. Just an idea though. ;) It would sure make our job a lot easier! Our team has a lot of work to do before the race next November!

  12. Re:Wonderful on Viral Fossil Brought Back To Life · · Score: 1

    Actually, the net force anywhere inside a symmetric spherical shell of matter is zero. Do the math. ;)

  13. Re:why would matter be dark on Dark Matter — "Alternative Gravity" Team Responds · · Score: 1
    Do high-energy (ie: high mass) photons have a gravitational effect? Or do the formulae only work given a rest mass?

    The gravitational effect is always due to relativistic mass, not rest mass. You can think of it as the total energy. So, yes, photons have a gravitational effect based on their total energy.

  14. Re:It's worse than that! on New Code Discovered in DNA? · · Score: 1

    More like 20 instructions (Amino Acids). The 4 nucleotides aren't the instructions themselves, but are more like two-bits or a single base_4 digit. Each amino acid is coded for by three nucleotides (a codon). This covers the coding of 20 amino acids with some redundancy.

  15. Re:Comments on Slashdot aren't reliable either... on VW Raises the Bar for Self-Driving Vehicles · · Score: 3, Interesting
    Right, and do you know what is the order of magnitude of those naturally occurring forms of error? Let's see: ionospheric refraction, considering scintillation activity is in the order of 1.5 meters. Tropospheric refraction is about 2.2 meters. Code multipath is 1.5 meters. Adding these we have an RMS error of 3 meters, even ignoring other factors, like antenna gain and receiver noise temperature.

    And your point is? These types of errors you list (including satelite path deviations) are presisely what DGPS corrects for if the well known GPS is in relatively close proximity to the onboard GPS. In that case, these unknown variabilities will be reasonably well correlated so they will be removed when taking the differential. (ie. satelite orbit changes, ionospheric refraction etc., though unpredictable, will be nearly exaxtly the same for both GPSs so it gets subtracted out). In my work we generally get DGPS accuracies of less than half a meter which is well below your quoted error of 3 meters RMS.

    For use with autonomous vehicles, one can generally do a lot better when the DGPS is augmented with a ground based equivalent of GPS like Terralites (XPS) which can and do routinely give accurate positions in the 1cm range.

  16. seriousness of the matter? on Library Chief Criticized for Requiring Subpoena · · Score: 4, Insightful
    " 'It was an absolute misjudgment of the seriousness of the matter,' Horn said."


    Apparently the police didn't think it was even serious enough to bother getting a subpoena.

  17. Re:Degaussing Technique on A New Technique to Quickly Erase Hard Drives · · Score: 1
    It wouldn't, but you're nearly right. Simply placing a conductive object inside a magnetic field does nothing at all. In order for something to happen there must be motion. ... Powering down the coil slowly accomplishes nothing directly

    You're nearly rightm but have you by chance ever heard of 'relativity'? Whether the magnetic field intensity is changing due to motion or due to the source intensity changing... they both can produce the same effect which is to have the hysteresis curve shrink until the dipoles are left in random states. I'll bet that with a little googling you can find a lot of articles that explain the demagnetization process. You may even be able to find a Wikipedia article on degaussing. :)

    ...or were you under the mistaken assumption that something actually moved when you hit that degauss button on your CRT monitor? ;)

  18. OT - Re:Ubuntu server on Multi-State Family Networking? · · Score: 1
    Only problem was finding FTP clients for Windows...


    Try the FireFTP extension for Firefox.

  19. Re:stop the jpegs! on The Future of Digital Camera Technology · · Score: 1

    Since posting, I've noticed that some cameras don't report true pixel counts but use interpolation to generate their output. In this case, each photo detector contributes to three pixels in the output. You have to look at the specs of each CCD technology used to determine what their "megapixel" rating actually refers to.

  20. Re:stop the jpegs! on The Future of Digital Camera Technology · · Score: -1
    Each 'pixel' in a digital camera only has one color (red, green, or blue typically, sometimes white (Sony), other colors could be used)

    That is wrong. What you're describing is often called a "sub pixel". A pixel in digital imaging is usually defined as a combination of red, green and blue sub pixels. For a Truecolor image, that means that each pixel has 24 bits (8 bits per sub pixel). For a raw 13MP image that's 39MB.

    A one megapixel camera has one million blue photo detectors, one million red photo detectors and one million green photo detectors.

    (here's another link for you)

  21. Encryption?.... on Medical Data on 365,000 Patients Stolen · · Score: 1

    So... the data was obviously encrypted, right? AFAIC that should be standard operating procedure with offsite backups of sensitive data.

  22. Re:Mitochondrial DNA! on DNA of Woolly Mammoth Fully Sequenced · · Score: 1

    "Although information can be more informative." is not a fragment?

  23. Re:that's more like it on Company Develops Microwave-powered Water Heater · · Score: 2, Interesting
    this is supposed to be an improved _electrical_ option for places that don't have gas.

    Well, it's not improved. The microwave idea is *highly* inefficient and this article sounds like someone advertising for VC. When I was in Argentina over 20 years ago they had electric on-demand heated water (at the tap). It worked fine and I expect that they have better ones now. Getting heat to the water efficiently is a pretty simple matter. You have something to increase the surface are of the heating element relative to the water just like a CPU cooler does and as long as the surface area per volume is high enough, you're fine. It's not rocket science you know.

  24. Re:Touch on Using Gravity To Tow Asteroids · · Score: 1

    My point was that a rocket engine would have to be pointed so that the rocket's exhaust avoids the asteroid, otherwise it will only result in pushing the spacecraft and asteroid apart. So at a minimum you need to have a moderate distance between the spacecraft and the asteroid (reducing your max gravitational force) and would then require multiple engines (for thrust balancing) pointed obliquely enough so the rocket exhaust misses the asteroid.

  25. Re:Sorry, but this won't work. on Using Gravity To Tow Asteroids · · Score: 1

    Thanks for the info. I need to avoid slashdot late at night when my brain's already shutting down. ;)