Follow Slashdot stories on Twitter


Forgot your password?
For the out-of-band Slashdot experience (mostly headlines), follow us on Twitter, or Facebook. ×

Comment: 5% seems really unlikely (Score 2) 117 117

There is some loss of laminar flow, but 5% seems wildly optimistic for eliminating bugs under any normal sort of operation. I only fly piston planes so maybe someone flying jets can comment, but 5% is enough to affect your fuel reserve calculations and I've never heard of a "bug" correction.

Comment: Re:How frequency-specific (Score 1) 64 64

Looks like they have seen 99% reflectivity. Q must be on the order of 100 (give or take a pi and a 2). That is OK, but mirrors above 99.99% are commonly available at a single wavelength and I think they can get down to a few ppm with enough effort (and in clean conditions). I haven't worked with low loss mirrors in decades, so I don't know where the state of the art is now.

Comment: Re:What I find most disturbing is... (Score 1) 327 327

Good presentations are valuable. They convey important information. Bad presentations are a waste of time.

Powerpoint makes it easy to produce bad presentations, but it allows you to produce good ones.

Bullet points are useless if they contain no information "Improve product market share!". "Reduce failures".

Bullet points are valuable if they remind the audience of specific points: "Balance IP3 and Noise at each stage of the RF chain". "Using too high a gain in the first stage of a RF receiver is the most common mistake".

Used incorrectly, fancy graphics can be useless or distracting.

Used correctly, fancy graphics can illustrate a complex process such as the operation of a transverse deflection cavity for femtosecond timing measurements .

Comment: Re:And in other news (Score 1) 295 295

The question is *why* more men than women want a career in science (if that is true).

Is it due to some innate biological difference? Is it due to discrimination or harassment when they try to enter science? Is it due to a wide range of subtle societal pressures that are difficult to quantify?

I think the best we can do is to look for and eliminate any detectable discrimination and try to ensure that women have the same opportunities as men.

One thing to do is to study why the ratio of men to women is quite different in different technical fields.

Comment: Re:I was working at IBM at the time (Score 1) 387 387

I was an OS/2 user for a while. The problem I found was that major applications (like Lotus123) were more expensive on OS/2 and were often older variants. Since OS/2 had a windows compatibility mode I used that to use cheaper / newer apps. The compatibility mode seemed no more stable than windows itself (not really surprising). so I eventually decided running OS/2 was just an affectation and went back to windows.

By the time OS2 came out, IBM just didn't have the muscle to drive the entire market anymore. I suspect it would have also died if it did not have a compatibility mode, but I think windows compatibility doomed it for sure.

Comment: Re:The data (Score 1) 173 173

How does this work?
Hackers claim they have a huge database of embarrassing information. How do they prove that they didn't simply invent the information?

I have a "database" showing that Senator XYX has as thing for furries and garden implements. See - here I have a text file with Senator XYZ's name and a list of preferences......

You could take any list of names and add arbitrary kinks, then threaten to release them. How do you show that this is the *real* database and not one you made up?

Comment: Death is too much publicity (Score 1) 649 649

He is a murderer and some will say he deserves to die. But - a death sentence will keep his name in the news for a long time. Better that he be locked up and forgotten.

Personally I do not support the death penalty. It is too rare to be a deterrent. Too irreversible if there is a mistake. Too barbaric for a civilized society.

Comment: Re:No (Score 1) 515 515

That is why I go by rail not air in Europe China, Japan, Korea - even though it is often more expensive than air.

The key will be whether we can avoid the PITA issues in California HSR. If they want TSA, cheked luggage, 1 hour prior check-in and advanced reserved seats for reasonable prices, then I'll just fly. The flight itself is so short that the discomfort really isn't an issue. Its all the end effects that matter.

Comment: Re:This again? (Score 1) 480 480

There are still a lot of ways for the experiment to get the wrong result in vacuum. The force is really quite tiny.

Their "hard" vacuum was 1e-6 torr scale. That might still be enough to to produce some force. There can be effects from temperature causing anomolus forces in the suspension mechanism. There can be magnetic field effects from power cables. Torque from RF cables getting warm.

This would be a very difficult experiment to do correctly. Without details, it is much more likely that they got it wrong, than that they have found a violation of conservation of momentum.

As an aside, quantum mechanics still conserves energy and momentum. The pushing on virtual particles from the vacuum doesn't work unless you add enough energy to turn them into real particles - and then you just have a photon drive variant (which would produce far less thrust).

Comment: Re:Enough of this (Score 2) 250 250

Even though this bug isn't a direct threat, it could interact with other future software changes. If it is a counter overflow there is a risk that the counter would run at a higher rate in some future version where more functionality is needed. If 248 days went to 2.48 days, it might not be caught in testing, but could (rarely) happen in real life.

Comment: Re:Science requires a certain agnosticism (Score 2) 480 480

There is an old saying that you should keep your mind open, but not so open that your brains leak out.

When someone claims a violation of very well tested physical laws, AND that violation is not under some new unusual condition, it is very reasonable to be skeptical.

It this was seen with TeV protons at LHC, or in ultra-strong electric fields, or in strong gravity, or other unusual conditions it would be different. Physicists paid attention to the (later dis-proven) FTL neutrinos from CERN because that experiment was a new measurement under different conditions (very high energy neutrinos). We all expected (correctly as it turned out) that the effect was an instrumentation error, but we paid a lot of attention because it was possibly it was something extraordinary. This isn't.

Philosophy: A route of many roads leading from nowhere to nothing. -- Ambrose Bierce