Can the defendant even be compelled to open a safe? Suppose you have a case in which the defendant has either specifically disclaimed ownership of the safe in question or disclaims any knowledge of the combination or has flatly refused to either confirm or deny ownership of the safe or knowledge of its combination on fifth amendment grounds. I'm no lawyer, but I suspect the standard procedure in such cases is that the judge issues a warrant that permits police to access the contents of the safe and no burden is placed on the defendant to do anything at all. Rather, because they have a warrant for the contents of the safe, the police are entitled to open it and they do just that, using a locksmith or mechanical means to force it open. The analogous situation with respect to encrypted data would be that the police are welcome to crack the encryption themselves by whatever means they deem appropriate, but the defendant isn't required to do their work for them.

The problem is that the people assigned to cover science for the mainstream press generally don't understand what they are writing about and, I strongly suspect, because they operate under constant deadline pressure they never even read the scientific literature. They just interview the scientist who did the research and interview another scientist in the field for another perspective and report the most interesting "sound bites" from those two interviews along with a bunch of horribly naive (and often flatly wrong) conjectures about what it all means. You can't really blame them. They're journalists. Most of them majored in journalism, English literature, political science, or history in college and probably never took a science course above the 100-level at any time in their entire undergraduate program. What we need is more Richard Dawkinses, Michio Kakus, and Carl Sagans - academics who take on the task of explaining science to non-scientists. The way you get that is by creating the funding apparatus to make it happen. Academics are quite sensitive to the priorities of funding agencies - they rapidly become very interested in research topics for which funding exists. :) If funding exists for a professorship focused on enhancing the public understanding of science, there will inevitably be plenty of academics competing to fill that position.

Page hits isn't a very good metric if you're trying to get feedback about what viewers actually thought of the videos. A lot of people have heard of Khan Academy through the news or may land there via a search engine. How many of them watch the video all the way through? How many stick around and watch parts II, III, etc.? I could be totally wrong about this (please correct me if that is the case), but my suspicion is that YouTube's stats probably aren't sufficiently granular to distinguish between a page visit in which the viewer watches the video in its entirety (suggesting that the video was perceived as worthwhile) and a visit in which the viewer watches for a little while and then bails (indicating that it was not perceived as a valuable experience). User comments are subject to a great deal of self-selection bias. Viewers who thought the video was the best thing since sliced bread are way more likely to take the time to login (if already registered) or register and login (if not already a registered YouTuber) than those who thought it was a waste of time.

There's also a more fundamentally important question to consider: Did the viewer actually learn the material or were they simply duped into a false belief in their own competency? HN regularly features posts about interviewing techniques aimed at sorting out real programmers who can write code proficiently from people who simply possess a false belief that they are programmers. Sound pedagogical methods require some means of verifying that the student has, in fact, built a valid mental model of the subject matter and, of particular importance in the sciences, is capable of applying their knowledge to reason about novel situations. How do you know that your students actually understand the material? Do you have any way of distinguishing between students who have had a previous formal learning experience with the subject matter and are simply looking for a refresher course, students who are concurrently receiving other instruction (the teacher is using Khan Academy as a supplement), and students who have had no prior exposure to the material?

result = (A-B)./A*100;

Now I can just use the isfinite function to produce a matrix of logical values that tells me which pixel locations have valid values (simultaneously handling the case of numerical overflow). Granted, this doesn't do much to simplify the code above. We could have just checked beforehand to find the pixels of A that had zero values. However, if you have a complicated expression involving multiple divisions, logarithms, or other functions that are undefined for some portion of the real numbers, treating these situations as "recoverable" in some sense allows you to write cleaner, more readable code if your implementation language permits you to just do the operation and check for NaN values (+Inf and -Inf too) afterward.

BTW, it would have been nice if the journalist had bothered to consistently spell the doctor's name correctly (it's Siegel, not Siegal).