Практикум

А

ZERO-POINT MOTION IN A BOSE-EINSTEIN CONDENSATE has been quantitatively measured for the first time, allowing researchers, in effect, to study matter at a temperature of absolute zero. According to quantum mechanics, objects cooled to absolute zero do not freeze to a complete standstill; instead, they jiggle around by some minimum amount. MIT researchers measured such “zero-point motion” in sodium BEC, a collection of gas atoms that are collectively in the lowest possible energy state. According to Ketterle, “the condensate has no entropy and behaves like matter at absolute zero.”

The MIT physicists measured the motion (or lack thereof) by taking advantage of the fact that atoms absorb light at slightly lower (higher) frequencies if they are moving away from (towards) the light. To determine these Doppler shifts (100 billion times smaller than those of moving galaxies), the researchers used a technique known as Bragg scattering. In this technique, atoms absorb photons at one energy from a laser beam and are stimulated by a second laser to emit a photon at another energy, which can be shifted upward, or downward depending on the atoms’ motion towards or away form the lasers. Measuring the range in energies of the emitted photons allowed the researchers to determine the range of momentum values in the condensate. Multiplying this measured momentum spread (delta p) by the size of the condensate (delta x) gave an answer of approximately h-bar (Planck’s constant divided by 2 pi) – the minimum value allowed by Heisenberg’s uncertainty relation and quantum physics. While earlier BECs surely harvested this zero-pint motion, previous measurements of BEC momentum spreads were done with exploding condensates having energies hundreds of times larger than the zero-point energy.

ACCOUSTIC-DEPENDENT FRICTION. Studies of friction are often carried out at modest relative speeds: the two moving surfaces in question typically slide past each other at 1 cm/s.

However, researchers at UCLA wondered if new mechanisms might appear when surfaces slide against each other at higher velocities, such as those associated with friction between tectonic plates during earthquakes.

Observing the jerky “stick-slip” motion of a steel block riding on a rotating steel table, the researchers carefully measured the friction forces for relative velocities up to 0.35 m/s, by monitoring the expansion and compression in a spring attached to the steel block. At these high velocities, they noted that the significantly increased production of sound waves (largely neglected in past analyses) dissipates a large amount of energy, stealing away some of the energy of motion required for two surfaces to slide past each other and thereby amounting to an increase in friction. This suggests that the generation of sound waves between two sliding fault surfaces during an earthquake may provide a significant feedback mechanism that mitigates a quake’s effects, by converting energy of motion (friction which might otherwise have caused fracturing in the Earth) into sound energy.

B

What’s At Steak in the Euro-American Trade War by Ian Cooper

Whenever a quarrel erupts between the U.S. and another country, it inevitably creates a furore in the other country – with extended rants against American imperialism – but often passes with no media attention whatsoever in the U.S. itself. Americans may therefore be forgiven for being blissfully unaware that they are now in a full-blown trade war with the European Union.

Last week, in a little town in France, 150 farmers occupied a McDonald’s restaurant. I kid you not. They were protesting against the retaliatory tariffs newly imposed by the U.S. (along with Canada, alas) on some European luxury products such as foie gras, Roquefort cheese and Dijon mustard. The farmers put up posters that said, “No hormones in foie gras country.”

Without going into the – very complex – details, there are, in fact, four separate and ongoing disputes, concerning four products the Americans are selling which the Europeans don’t want to buy: hormone-treated beef (the cause of the present spat), genetically modified foods, dairy hormones, and bananas. Apparently, it is a top priority for this U.S. government to make the world sale for… drugged-up cows.

The interesting thing to me is that three of these disputes arise from a European distrust of American high-tech food; collectively they illustrate some important differences in gastronomic attitudes on either side of the Atlantic. (I cannot, however, find any deep cultural meaning in the dispute over bananas.) To defend their resistance, the Europeans cite three high-minded concerns: public health, animal welfare, and the environment. In response, the Americans assert that high-tech food is not only safe but in fact a great boon to mankind; they accuse Europe of thinly disguised protectionism.

For the record, it is my opinion that the Europeans’ stated concerns have merit; these foods have not been proven to be safe. (It should be noted also that the Europeans do not exactly have a perfect public health record, having had a number of food scares recently.) But I think that the real reason behind the European intransigence is not as high-minded as they would have us believe; on the other hand, it is not mere protectionism.

The fact is, Europeans are snobs about food. And they feel particularly superior to Americans, whom they believe to be about as discriminating as three-year-odds when it comes to what they put in their mouths. The European attitude of culinary superiority translates into a general conservatism about farming methods, and an inherent distrust of anything new-fangled, especially from the U.S.

One can’t help but suspect that the trans-Atlantic rift is more about culture than about agriculture. Europeans reject hormonally enhanced American beef not because they think it is hazardous or morally wrong but because it is tasteless. It is essentially the same reason that they reject, say, tasteless Hollywood movies with hormonally enhanced stars.

If you want proof that any European animal-welfare argument is disingenuous, then look at foie gras, one of the targets of the new American tariffs. It is a pate of goose liver, involving the “traditional” method of force-feeding the unfortunate creature until its liver balloons to many times its normal size. (Delicious, by the way; try it on toast.)

Put simply, Europeans resist pumping their cattle with hormones not because they want to make Elsie’s time on earth that much more pleasant, but because they love a good steak.

Americans do love a good steak as well; but they don’t seem to mind their steak from a pumped-up Nietzchean Supercow, or their milk from a Frankenstein Holstein, or their tomatoes from a genetic laboratory. For some reason – lack of information, lack of choice, or both – Americans have a much higher tolerance for food that has been pesticized, hybridized, genetically modified, and hormonally enhanced to the point of tastelessness.

(I exaggerate, of course. There is one group of American consumers who are very well informed about farming methods, and care deeply about the way livestock are treated. They’re called Vegetarians. Unfortunately, they are the one group, which has no leverage with beef producers.)

American attitudes may yet be changing. A growing market in organic milk (free of hormones, pesticides and antibiotics) is one indication that Americans are questioning the dubious products which agribusiness shoves down their throats.

But for now, let’s have three cheers for the European Union. Their finicky feelings about food at least provide one effective defense against the relentless juggernaut of bioengineering. I hope they keep up the fight, even if it means I have to pay a little more for fancy mustard in the meantime.

C

Top 10 Things you’ll NEVER hear a woman say, that men would love to hear

10. You know, I’ve been complaining a lot lately.

I don’t blame you for ignoring me.

9. The new girl in my office is a stripper.

I invited her over for dinner on Friday.

8. While you were in the bathroom, they went for it on fourth down and missed.

If they can hold them to a field goal, they’ll still cover.

7. Bar food again??? Kick ass!!!

6. I liked that wedding even more than ours.

Your ex-girlfriend has class.

5. I love hearing stories about your old girlfriends. Tell me more.

4. Let’s just leave the toilet seat up all the time; then you won’t have to mess with it anymore.

3. It’s only the third quarter; you should order a couple more pitchers.

2. I’m so happy with my new hairstyle, I don’t think I’ll ever change it again.

1. I love when my pillow smells like your cigars and scotch.

You passed out before brushing your teeth again, ya big silly!

A State Trooper pulls a car over on a lonely back road and approaches the blonde lady driver.

“Ma’am, is there a reason that you’re weaving all over the road?”

The woman replied, “Oh officer, thank goodness you’re here! I almost had an accident. I looked up and there was a tree right in front of me. I swerved to the left and there was another tree in front of me. I swerved to the right and there was another tree in front of me!”

Reaching through the side window to the rear view mirror, the officer replied, “Ma’am… that’s your air freshener.”

A football coach walked into the locker room before a game, looked over to his star player and said, “I’m not supposed to let you play since you failed math, but we need you in there.

So, what I have to do is ask you a math question, and if you get it right, you can play.”

The player agreed, so coach looked into his eyes intently and asked, “Okay, now concentrate hard and tell me the answer to this. What is two plus two?”

The player thought for a moment and then answered, “4”?

“Did you say 4?” the coach exclaimed, excited that he had got it right.

Suddenly all the other players on the team began screaming…, “Come on coach, give him another chance!”

School Daze

Two collage seniors had a week of exams coming up.

They decided to party instead.

Their biggest exam was on Wednesday and they showed up telling the professor that their car had broken down the night before due to a very flat tire and they needed a bit more time to study.

The professor told them that they could have another day to study.

That evening, both of the boys crammed all night until they were sure that they knew just about everything.

Arriving to class the next morning, each boy was told to go to separate classrooms to take the exam.

Each shrugged and went to two different parts of the building.

As each sat down, they read the first question.

“For 5 points, explain the contents of an atom.”

At this point, they both thought that this was going to be a piece of cake, and answered the question with ease.

Then the test continued.

“For 95 points, tell me which tire it was.”

RULES OF THE AIRWAYS

- Takeoff’s are optional. Landings are mandatory.

- Flying is not dangerous; crashing is dangerous.

- Speed is life, altitude is life insurance. No one has ever collided with the sky.

- The only time you have too much fuel is when you’re on fire.

- Flying is the second greatest thrill known to man… Landing is the first!

- Everyone knows a ‘good’ landing is one from which you can walk away. But a ‘great landing is one after which you can use the airplane again.

- The probability of survival is equal to the angle of arrival.

- Was that a landing or were we shot down?

- Learn from the mistakes of others. You won’t live long enough to make all of them yourself.

- Trust your captain.. but keep your seat belt securely fastened.

- Be nice to your fist officer, he may be your captain at your next airline.

- Any attempt to stretch fuel is guaranteed to increase head-wind.

- A pilot is a confused soul who talks about women when he’s flying, and about flying when he’s with a woman.

- Try to keep the number of your landings equal to the number of your takeoffs.

- There are old pilots, and there are bold pilots, but there are no old, bold, pilots!

- Gravity never loses! The best you can hope for is a draw!

- Gravity SUCKS!!!