Since sapphire is already 100% aluminium oxide, but arranged in a crystal lattice I think it should be stable in contact with mercury unless the mercury disrupts the lattice (a possibility--my physical chemistry is weak).

An example: say we want to know how a drug affects cognition. We give a simple test to a bunch of people on and off it, blinded, etc. The control group's average score is 74, and the test group's average score is 72. We can use a t test to see if there's a statistical difference, and find there isn't. We can't conclude anything about the drug.

Now imagine we have exactly that same data, but we were careful to give two tests to each person (in a random order, and different tests, of course). We take another look at the data and find out that every single participant scored lower when they were on the drug. With even a fairly small sample size this provides strong evidence that the drug impairs cognition, and probably tells us quite a bit about how much it does.

The article is probably talking about multivariate regression; the more important number comes a few sentences later---"retention was related more strongly to manager quality than to seniority, performance, tenure, or promotions". So presumably, they did the same sort of analysis, carefully pairing people who were similar in as many ways as possible, and found out that good managers are more important than seniority in terms of employee retention. The more variables you have, the more even large differences can hide in raw group averages.

A huge number of Chrome users go to google.com to search for things; if the new page looks like the Google search page, and it moves your cursor to the address bar, Google hopes these users will learn that you can just search from there. Maybe it's an experiment that will fail, but it seems like it might work.

Gmail ad targeting isn't a bit of JavaScript that can run in real time in the background. It's a series of huge map reduces touching data sets larger than any client computer could store. Just indexing a pre-prepared list of mothership ads would result in a horrible user experience (far poorer ad targeting).

Google has a vested interest in only showing you ads you might be interested in; it doesn't work as well as it should, but it works magnitudes better than the state of the art 10 years ago.

You only have to prove people know you by a name if you want to go by "#RS", "Albert Einstein", or "GreenLife Rx"; all three of those are likely name violations for reasons that have absolutely nothing to do with knowing who you are.

Someone who habitually sleeps 6 hours a night but never feels tired is probably fine. Someone who habitually sleeps 8 hours a night but always feels tired should try sleeping more, and if that doesn't work they should seek advice from a doctor.

I expect there is a large segment of people who suffer from sleep deficit and would be more effective if they slept more, but don't know that it would help them. I don't think this is the correct way to reach such people, or the correct message to give them.

"Alcoholism was the main cause of divorce between the Grant Study men and their wives"

Don't really give us that much of a clue about how alcoholism (for instance) affects everyone else. I suspect it's similar; but this doesn't give us any data on anyone who isn't in a very very specific group.

The delivery windows go as late as 9pm, so I'm sure they will try to push back the last time at which you can order and still get it delivered same-day.

ETA response to the second question: I'm very happy with the display. That's probably as much as I should say, and I don't know the actual details anyway.

I think the danger comes from people who get text messages while they're driving and want to look at a shared photo. That should be disabled while driving, which glass can make a pretty good guess at.

Comments URL: https://news.ycombinator.com/item?id=5180684

Points: 10

# Comments: 1

Just my experience; I started at the beginning of 2012.