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 .

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.

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.

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?

But that isn't how we execute people. We spend millions of dollars and pay to keep them in prison for many years. In the end it can be more expensive than a life sentence.

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.

No, they checked. In the video you can see it goes dim then black when it gets out of sunlight.

It was worth checking though.....

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.

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).

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.

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.

I have spent my life (or at least 35 years) studying physics and doing experiments, many of which include high power microwaves.

There are a lot of ways for them to have gotten this wrong, and it violates very fundamental physics principals. They can publish in a refereed journal with enough details to satisfy other physicists if they really have something.

If you use energy to create real particles out of virtual ones, you are building something very like a photon drive. Its just like an LED converting electricity to matter (photons). Those photons produce thrust - but the thrust / power is extremely tiny. This limit applies to any sort of particles you might produce.

There are a number of concepts for accelerator driven nuclear reactors. Nothing fundamentally crazy, just none have been made practical yet. I don't know if there is enough room to increase the efficiency of generating and collecting neutrons - it may be that you just can't quite get there. Similar situation to muon catalyzed fusion. It *almost* works, but the muons stick to the helium after it is formed and you can't quite come up with a scheme where it is a net energy producer.

Theses sorts of concepts are being looked at - they may eventually get one to be practical, but so far no.

Its not easy to measure 50 micro-newtons of force when you change a power level by 50 watts.

Currents cause magnetic forces. Things get hot and outgas producing thrust. RF power cables get hot and distort causing a force.

Think about it. The device weighs something like 5Kilos. That is 50 newtons gravitational force. So a 1 micro-radian tilt will cause a 50 micro-newton force. Walking across the lab floor could cause that amount of deflection. If the chamber is 1 meter across, a 0.1 degree temperature change on one side of the chamber (from a nearby power supply) could cause that much tilt.

There of course could be force just from photons - but that is a simple and well understood photon drive - known for at least 50 years now - basically a light-sail.

This is a very difficult experiment to do correctly, and they have not published in enough detail.

Meanwhile: conservation of momentum has been tested under conditions ranging from ultra-cold gas atoms to 100GeV particle collisions, to orbiting neutron stars. The RF fields they use are very modest. At SLAC we run hundreds of megawatts, not 50 watts. We have superconducting cavities where we easily see the deflection caused by the momentum in the microwave fields - operating at many thousands of times higher power than this experiment - we see nothing unexpected.

So: Difficult experiment. No unusual physical conditions. Apparent violation of one of the most carefully tested conservation laws in all of science.

It it literally more likely that the sun will not rise tomorrow (since that is also based on conservation of momentum) than that this experiment was correct.