Friday, April 29, 2011

Large Experiments

When an experiment takes a decade to build, or involves more than a couple hundred people, or the people are spread out over wide areas, understanding is lost.

When I was a graduate student, it was still quite common for a student to build part of the apparatus, write or help write the software for unpacking the data, and do analysis and simulation.

Now the subdetectors are generally too big for one person to build, and so you need engineers and a team of technicians and an experienced supervisor (at least I hope you get one!), and it takes several years to do.

So what does the graduate student do? Write software. Simulations, analysis, monitoring, sometimes data acquisition. It has been startling to see some of the reports students present at the local group meeting. Their professors are experienced and on the ball, and correct them appropriately, fortunately; but most of the students had no feeling for what noise and failures would do to their ideal projections ("find a Z-prime signal in the first month"). A week or two with a prototype chamber and readout would give them a lively distrust for the answers computers come up with.

And, of course, the time to build takes so long that it now takes several generations of graduate students before they start seeing real data—and the unlucky ones have to find something to write up for a dissertation in the meantime. Something is missing when students only sample the output end of experiment. I know it seems ideal: come up with an idea, somebody else funds it, builds it, runs it, and you get to just analyze the results. Still, the friction tells you something important.

I do not know why it is so, but you share much more information face to face than over a video link, and of course far more than with email exchanges. There is no substitute for sitting down in the same room with a colleague and a sheaf of notes and maybe a laptop or two to show diagrams on.

My colleagues are on several continents. Just the trip from Wisconsin to Fermilab is an impediment to real ease of communication; being in different time zones cuts hard into the sharing. The rule has always been that the experiment site/headquarters is the place to be.

I’m glad CERN’s wireless service in the cafeteria is slow. It has always been a famous place to talk and learn, and frequently much better than the Powerpoint presentations in the working groups, and it is sad to see people hunched in isolation.

In the working group meetings, everyone has a laptop. Some with less than spectacular eyesight, or with some question about one slide or another, are reading the presenter’s slides. Many are answering email or writing presentations of their own, or some analysis project. Some I’ve seen buying airline tickets, reading the news, and the grad students often read online comics (amazing what you can see from the back of the room). Rarely are the presentations self-contained—they are almost invariably updates on existing work. If you show up as a newbie you will be at sea for the first few meetings.

And that is a serious problem. Because experiments like CMS are so large you need many teams of people to manage the subdetectors and figure out how to process the data and work around the problems. So typically a scientist will be an expert on one aspect of one or two subdetectors, and have only a general notion of how the others are performing. It doesn’t help to show up at meetings for the other working groups—there aren’t enough hours in the day, and they don’t have time to explain everything from scratch at every meeting. CMS has tried to deal with this by selecting people whose job is to communicate to other subgroups—but it really helps if you are at CERN. And most of us aren’t. (Especially not me after that last budget cut. And the Tevatron shuts down 1-Oct unless it breaks early.)

IceCube had a collaboration meeting/inaugural celebration this week. They’d finished drilling and installing all 86 strings of detectors in Antarctica, and everybody was happy. I found the plenary talks wonderful—they explained what was going on, and the meaning of the historical datasets that I’m trying to get into the data warehouse, and what they’d been trying to do and were planning to do next. Reeder noted that it was quite an accomplishment to build such a large detector and have the top people all still speaking to each other, and apparently still liking each other. And on time and on budget.

Halzen had a wild idea, and enthusiasm and drive and a skill for explaining what it was about to funders, politicians, and the man in the street—and now the largest detector in the world is buried in the ice and being used to attack dozens of questions. OK, it will take years of data collection to detect some of the types of signals they want, unless a star in our galaxy decides to cooperate and go supernova for us, and there are still no unambiguous extraterrestrial neutrinos. But still.

The place to be is not the South Pole (although most folk want to have been there—except Halzen himself). I don’t know yet if there is a center—I’ll learn more as I work here. Germany, Sweden, Belgium, New Zealand, USA? I wonder what difference it will make to be so decentralized. Perhaps the apparently somewhat laissez faire physics coordination comes from being a distributed culture.

Wednesday, April 27, 2011


For the record.

Sunday, April 24, 2011

Beating back malaria

Researchers hope to breed mosquitoes which are not infected by malaria, in hopes that these, spreading through the wild, will displace the infectable ones. No infected mosquitoes means no infected people. Similarly, fewer infected mosquitoes should mean fewer cases.

They were able to get a gene to spread to half the population in several different (captive) environments. That's good; other groups have developed some malaria-resistant mosquito strains. One can hope.

There's a slight fly in the ointment, though--minor compared to the hope of getting rid of malaria, but not entirely trivial: Unless the gene gives the mosquito an advantage, the gene will likely disappear. Better mosquitoes?

The group thinks they found a way around this; they use a (already known) gene that makes a chemical which, when the cell repair machinery starts up, cuts at that site on the DNA and uses the location as a template. So the gene always winds up present, no matter how the gametes divide. So we don't get super-mosquitoes. One can hope.

Laser Sparkplugs

BBC reports on a new proposal to use lasers as more efficient sparkplugs. They are now tiny enough that they can fit, and the light would cause more efficient ignition all along the laser path and not just right next to the spark.

Except: three things come to mind: shock stresses, heat stresses (they claim the ceramics are more robust than normal lasers, but still), and carbon/ash buildup on the optics. Can you imagine how often you'd have to clean your plugs if your rings got scored and you started burning oil? I'm finding it harder and harder to get at the spark plugs, thanks to space-saving engine compartment designs.

Saturday, April 23, 2011

High Speed Passenger Rail? Not so fast

From the Economist

America’s railways are the mirror image of Europe’s. Europe has an impressive and growing network of high-speed passenger links, many of them international, like the Thalys service between Paris and Brussels or the Eurostar connecting London to the French and Belgian capitals. These are successful—although once the (off-balance-sheet) costs of building the tracks are counted, they need subsidies of billions of dollars a year. But, outside Germany and Switzerland, Europe’s freight rail services are a fragmented, lossmaking mess. Repeated attempts to remove the technical and bureaucratic hurdles at national frontiers have come to nothing.

Amtrak’s passenger services are sparse compared with Europe’s. But America’s freight railways are one of the unsung transport successes of the past 30 years. They are universally recognised in the industry as the best in the world.

Apparently passenger lines mung up scheduling for freight, and I've heard that passenger lines never were profitable for the railroads even in their heyday. I'd not bother with a passenger line to Milwaukee--its faster to drive, and if I didn't have a car I'd take the bus (cheaper).

Thursday, April 21, 2011

Singleness of Purpose

We don’t multitask well, say the experts. I’m afraid my experience supports their claims. And Feynman found that some people could talk and mentally count at the same time, and others could not—he was one who couldn’t.

Some tasks partition well enough that we can come close to multitasking. When a knitter is expert enough she can concentrate on talking while her hands do the automatic motions.

Some tasks go together naturally—listening to music and joining in with song or dance, for example. Eating with friends makes the food and conversation better.


Gandhi is said to have believed so strongly in the dignity of work that he respected the effort that went into the making of each pencil—respected it strongly enough that he would not throw away that piece of work until the nub was too small to hold in his fingers.

Back before the University in its infinite wisdom redid the windows (it now gets colder in my office than it used to) I could pick up some radio stations and I’d sometimes listen to music while I worked. And then one day I realized I was missing half the detail while concentrating on something else. Sitting in a concert hall and doing nothing but listening brought out aspects I’d never heard before in a piece I’d heard dozens of times.

Apple pie can be great. Apple pie a la mode is a good contrast of flavors and textures and temperatures. Apple pie a la mode with chocolate drizzle and candy sprinkles? We’re not just talking diminishing returns here; the complex dessert is worse than the simpler one and the pie maker could justly complain about what we’ve done to her creation.

In order to hear consistently above the background noise of the road or the waiting room, music needs to be flattened dynamically. That leaves us with less to listen to in the first place. With some musician/singers in the family, and from listening to practice at church, I know the care that goes into getting each bit right—often my untrained ears can’t tell the difference—and I wonder what they think of their effort being treated so carelessly.

"Money can’t buy happiness," nor even rent it for long; the thrill passes and you need a bigger one, and a bigger—the handful of M&Ms isn’t enough anymore, you need a 8-oz bar, or perhaps even the "TurnGreen" 24-oz of chocolate stuffed with caramel and peanuts and coconut and drizzled with white chocolate, leisurely devoured while soaking in a whirlpool and listening to your favorite band and watching videos on the big screen and getting a neck rub.

’Tis the gift to be simple. One of the things we enjoy in children is their focus on the moment. Their "moments" don’t always last long—long term dedication is more of an adult attribute—but they’re often thoroughly involved while it lasts. It seems like a useful discipline to cultivate—doing one thing at at time. Life militates against it, of course. Creating this post lasted considerably longer than I expected, partly because people wanted to talk to me and they take priority. And I remember what life was like with little kids running about. But when I have the time to enjoy something, I don’t need to make it as complicated as the rest of the day.

Friday, April 15, 2011

Budget Cutting Rule

If a proposal promises $$BIG in savings but postpones serious cuts to some other year, that proposal is a lie.

Wednesday, April 13, 2011

150 Years

Despite my hectic schedule I've seen many articles on the grim anniversary of yesterday. So many things might have gone differently. The war would not have lasted nearly so long if Pinkerton's estimates had been more accurate, or McClellan had contemplated Eccl 9:10--and the fallout would probably not have been so bitter. The Confederacy could even have won, and that quite easily--by holding fire. Lincoln didn't have the backing to invade to retrieve secessionist states, and they could have waited him out.

Of course if the South had held fire and successfully seceded there'd still have been war--probably several, especially around World War I when the European powers would have had proxy battles among the various "American" and Mexican countries.

And of course both main classes of commentators are correct: the war was about slavery, but the soldiers weren't inspired to fight by economic theories but by home and family, as usual.

Friday, April 08, 2011


I don't seek out the political news, but the breathless headlines that Trump was high on the list of Republican candidates for president were hard to avoid.

Do we really need another vanity presidential candidate? Given the precedent, I'm not sure Trump would take the job unless he was promised not just a Nobel Peace Prize but the Physics Prize and an option on getting to be the next pope.

Monday, April 04, 2011

1E-8 Caesar

Sometimes aspects of democracy can be irksome. If you take your role as responsible citizen seriously you have to study the problems of the city from within the limits of this world, since the city is not a creature of eternity and must not wait for divine justice. This mixes a little uneasily with attempts to discipline yourself to turn the other cheek. Your duty requires that you spend some of your time thinking like Caesar, when maybe you want to think like Christ.

Sunday, April 03, 2011

Church Fathers quotations

I'm reading selections from the early Church Fathers for Lent. Some I'd read before (Justin Martyr, Didache, etc) and others I hadn't (Ignatius of Antioch, life of Anthony, etc).

Of course I'd read Penguin Island (UPDATE: and Thais) and something by Twain (?) that parodied the Life of Anthony... So far the stories about him are a bit strange but when his advice is quoted it is pretty solid. The stories talk about haunting of devils and apparitions, but Anthony said don't worry about the devil since he was already defeated, and so on.

The quotations from the Bible are in quotation marks, of course, because they are recognized easily, even if the translation differs rather strikingly from the commonly used versions today. The writers either quote the Bible or refer to the author of the quote.

So far they don't cite non-Biblical authors. There seems to be no "Tradition" at this time apart from the inspired writers that they can cite. This is consistent with the model of "Tradition" which holds that people did the obvious thing with a tradition: they wrote it down.

Or are there non-Biblical quotations that we just don't recognize? I am no linguist and don't think I can change careers this late in the game for the sake of a curiosity, but it might be possible to put all texts in a common language and do some pattern comparisons (not trivially, since the authors paraphrased freely) to see if there are common sentences that might represent quotations from each other or some common authority.

Saturday, April 02, 2011


This morning I realized that yesterday was exceptional. For the first time since I don't remember when, I spent April Fool's Day without hearing an April Fool's joke, running across a prank, or reading a fake news story. Or attempting one myself, an effort I gave up long ago. The "no fake news" probably arose because I've laid off most news sources for Lent and the day was so crammed I didn't have time to read much of the few I retained.

I can't say I missed it. Kind of refreshing to think about it after the fact, truth to tell. We used to have a departmental April Fool's memo, which quit appearing after one fellow retired. The writer got the tone exactly right and the plausible buildup was good enough to keep you wondering until the second page--unless you read the date. Since I didn't invariably visit my mailbox every day, it wasn't always obvious.

But 99% of the attempts for the day just felt wrong: Banal, or dull, or unpleasant, or unbelievable. Want to send someone into brain freeze? Tell them to say something funny--but not tell an old joke.