We learned in grade school that it works because a lot of liquids, especially water, stick together. The water going downward pulls the water upwards because the whole amount in the hose is bonded together. THAT is how it works.

But if you fill a large diameter pipe with water then the water falls out of the pipe even if you keep the top end closed. Put a piece of card across the low end though and air pressure will hold the water in.

Based on looking at a drip, I'd guess that water doesn't have enough tensile strength to support anything more than a couple of mm of itself.

The claim in the paper (linked from one of the first comments) is that it's the tensile strength of water that allows the siphon to work.

For the case of water I think that's garbage. Water doesn't have enough tensile strength to support more than a very low siphon. It's air pressure that allows siphons of usable height. Because of it's relatively high vapour pressure while a liquid it's going to be hard to prove anything either way using water though.

Mercury would be a better bet. It has a very low vapour pressure.

If you set up a siphon so that no mercury is flowing (source and destination reservoirs are at the same pressure) then you can make it flow either way by lifting or lowering the reservoirs relative to one another. (You can do this with water too)

I predict that if you were to then move the apparatus to a vacuum chamber, the mercury in the siphon tube would come out due to gravity and there would be a vacuum in the tube too. Raising and lowering the reservoirs would then not cause any mercury to flow either way.

The energy captured in coal, gas, and oil is the result of many millions of years of sunshine. How, exactly, does one reasonably maintain an expectation that our releasing that in a matter of a couple decades should have no significant effects?

Except that the energy being released by burning all that fossil fuel is trivial.

Google gives me 144000TWh in 2008 world energy consumption. Call it 2x10^17Wh

Solar flux at Earths surface is around 2x10^17W. Geothermal is around 5x10^13W.
Almost 10^5 hours in a year, so Geothermal heating is about 4x10^18Wh/year

The heating from burning all that fossil fuel is small in comparison to the heating due to natural radioactivity in the Earth's crust which, in turn, is negligible in comparison to the energy from the Sun.

It's the CO2 that is the problem. Even though it traps a tiny extra fraction of that incoming solar radiation, a tiny fraction adds up to a lot of energy and it's year in, year out.

In order to test among our theoretical traditions, ... the policy preferences of economic elites (measured by policy preferences at the 90th income percentile); ...

That says that "economic elites" in their study are the top 10% not the top 0.1% or so.

They later say (page 18)

What we cannot do with these data is distinguish definitively among different versions of elite theories. We cannot be sure whether we are capturing the political influence of the wealthiest Americans (the top 1% of wealth-holders? the top 1/10th of 1%?), or, conceivably, the less affluent but more numerous citizens around the 90th income percentile whose preferences are directly gauged by our measure.

I'm not sure why you think the study talks about the 0.1% when they explicitly state that they're capturing the preferences of the 90th income percentile and they cannot distinguish the different versions of "elite theories".

Presumably to limit the opportunity for known plaintext attacks.

I don't know when this is used but I guess it's the only traffic on an otherwise quiescent connection.

But the question is, given that any musician's ultimate target is to eventually have an audience, shouldn't how an instrument sounds to them be the quintessential point of evaluating the quality of an instrument?

Not just that. Performing is totally intertwined with feeling and mood. It's quite possible that someone can play better on a $1M violin than on a $30K violin even when objectively, they're equivalent.

ISTR a study that found that watching the performances was more important than hearing them when picking out the eventual competition winners.

Found a reference:
http://www.bbc.co.uk/news/scie...

Also, these ancient strads have stood the test of time. Even if a modern violin is as great now - will it still be as great at the end of a virtuoso's career? Or perhaps it will improve with age. I would guess that the ancient violins are probably more stable (assuming equivalent care regime)

I'm not sure you really need 1-2 minute charging.

Assuming an all electric infrastructure.

Cars would start the day fully charged - no need to "fill up" on the way to work - because of an overnight charge and it's reasonable to assume that will be sufficient for a typical day for most people.

The remaining obstacle is long distance driving. A 30 minute charge time every 4-6 hours wouldn't be unreasonable but that would only work if there wasn't a queue before you got to start charging. That's going to mean a lot of charging points - and probably there would have to be batteries at each charging point so that the load on the grid can be smoothed.

And why is this a problem?

I'm looking to sell say 50K on two exchanges - and I need to sell so I'm going to accept the best bid.

markets A and B are both offering 1.00 bid with a 1.02 ask. 20K on market A and 30K on market B are available.

I put in my 20K to market A. and I get my $20K. HFT trader with wow whiz algorithm spots my 20K order on A and races ahead to get a 30K 1.01 ask on B before I get there.

I get $30.3K on market B. Your greedy evil HFT has just made me keep more of my money and give less of it to those greedy bank market makers with their excessively wide spreads.

Not really. That used to be possible but there are now so many people doing it that there aren't sufficient arbitrage opportunities to make enough money to cover your costs.

Instead it's more like this:

Consider a hypothetical stock that is worth exactly $1.

What used to happen was that the market makers would have a bid/ask of 0.95/1.05. (For a modern market that still trades with those sorts of spreads, look at gold metal. For small investors, a 5-10% bid/ask spread is fairly typical)

Someone came along and said, hey, I can make money even if I under cut the banks on both sides. So they started offering 0.96/1.04, another competitor, 0.97/1.03 until eventually you end up at 1.00/1.01.

Of course, in real life it's not quite that simple, the price actually moves. While the banks were offering 0.95/1.05, excepting exceptional circumstances, they don't need to update their prices all that often in order to avoid losing money. Of course, they do want to update their prices but it's a fairly leisurely process.

HFT traders can keep their spreads so low because they update their bid/ask prices constantly.

They make money, not by having a big margin, but by having tiny margins but capturing a lot of trade by having the best price. HFT has taken money from the banks and given it back to the investor.. The banks hate it and would love to see it stopped.

That said, there are things that (some) HFT firms are allegedly doing that aren't ideal. One of the things is to enter a new bid/ask into the order book and then cancel it again so quickly that nobody else can take advantage of it.

For example, current market 0.99/1.01. HFT puts in a 1.00 bid and then instantly cancels it again. People see that 1.00 order and try to move towards it - for example the person with the 1.01 ask might cancel it and enter a 1.00 ask instead to try and match the 1.00 only to find it's been cancelled in the 50us it took to react to it. The 1.00 ask now gets cancelled again but the HFT has now entered a 1.01 ask and is now front of the order book.

I have no idea how prevalent this is but if it is, it's easily preventable (orders have to be good in the market for a minimum (short) length of time before they can be cancelled) without having to lose all that is good in HFT.

The religious right are NEVER going to accept science

I'm in the UK and we don't really have a "religious right" here. I don't think we have as bad a problem as the US but the impression I get is that scientific illiteracy is something that people in the UK are less ashamed of than say people in Germany.

But the fundamental problem isn't the "religious right" it's that people are very emotionally tied to opinions they hold and it's very hard to accept that you are wrong.

(Good) scientists fight this natural human tendency all the time. I'm sure everyone who has ever done any sort of statistical analysis has got a result they didn't like (expect) and then pored over the calculations for hours looking for the mistake. Ditto, they've got the result they expected and then had to eat humble pie when someone else points out that they've slipped a decimal point somewhere.

Scientists, with all their training to look at things objectively and derive conclusions from the data, find this hard to do. How much harder must it be for people who can't repeat the calculations and just have to accept it when a scientist says "you're wrong".

Because science (nature) is brutal. It doesn't care what your opinions, hopes, beliefs are. It will trample over them as effortlessly as it will support them and with as little feeling.

there is lots 'coding around the problem' with special cases and branches all over the place

While this is undoubtedly the case, part of the cause is that the world is full of special cases.

The other half of the problem is that many programmers struggle to distinguish between a defect report that is due to a bad assumption about the general case and a defect report that is due to a special case that the general case doesn't handle.

So you get two possible issues - either they change the general case to handle a special case - and break something else along the way (which then gets fixed in its own peculiar way), or they add special case handling and fail to fix the general case. After 20 years of acquiring "bad" fixes like this the code becomes almost unmanageable and even identifying the special cases that would need to be handled in a rewrite are hard to impossible to determine.

Your post sounds to me like one of those "I'm ideologically opposed to the proposal, so I'll think of some problem that it has and invest zero thought into possibilities of how the problem could be solved, because I'm just waiting for you shut up about this issue that I wish we wouldn't even be talking about."

Ha! Precisely the opposite.

But I'm one of those completely state school (free/public for those in the US) educated bods who made it to Oxbridge.

http://www.telegraph.co.uk/edu...

My school advised me (prior to applying to Oxbridge) to drop further maths so I could concentrate on my other exams (which I refused to do). Of course, when I got my offer (Physics) I needed to pass further maths. I probably wouldn't even have got an interview if I'd dropped further maths and I'd have had no idea (nor the school). Quite frankly, I don't think I'd have survived the course without having done further maths in the sixth form.

Well, whether or not there was sexual harassment (illegal as hell, BTW, so that's a serious charge), it sounds like some bully (or bullies) found her achilles' heel, and exploited it.

Sexual harassment, like all other instances of harassment is not the case of "something really bad that should never have happened." That would come under sexual assault, or assault if it isn't sexual.

Harassment is when there's a prolonged course of incidents that individually are not particularly serious but when viewed as a whole, make someone uncomfortable and feel unsafe.

You're allowed to ask that co-worker out. You're allowed to say someone is looking lovely. But you'd better be sensitive to whether that comment is well received because constantly repeating it when it's not appreciated could constitute harassment. And if you cannot tell whether it's well received or not then better to not start at all.

Harassment is Chinese water torture. One drip never hurt anyone.

The problem isn't giving gifted children the opportunity to take advantage of their gifts.

The problem is that the wealthy will use their wealth to coach, and otherwise promote their average or slightly above average children so that they get into those places for gifted children in preference to the gifted poor child who can only score as average or slightly above average due to lack of opportunity and education.

I'm sure the same problem happens in the Asian cultures where this is the norm. There is possibly a difference in that educational excellence is seen as something to boast about and so a poor uneducated peasant who has an exceptional child will still want to see them enrolled in a gifted child program unlike in the west where ignorance is sometimes seen as a badge of honour.

The laws are reasonable - they allow costs to be offset when calculating profits.

The problem occurs because
A can sell to B at cost who can sell to C at the price that C finally sells for and the only person making any profit is B.

Perhaps the market is very competitive, A cannot sell above cost. C cannot buy at below the price B will sell at. (obviously in the real world A and C would need to make some profit but it's not inconceivable that A and C are working with margins of less that 5% while B is working with a 40% margin.)

Or perhaps A, B and C are all subsidiary companies of the same parent. It's still possible that A and C are in a very competitive market, or it's possible that the company is artificially moving profits to where they would prefer them to be.