Category: Science

“I know this will generate howls of protest, but at present a family of four going by car is about as environmentally friendly as you can get.”

Can this be true?

They [researchers] calculate that expresses between London and Edinburgh consume slightly more fuel per seat (the equivalent of 11.5 litres) than a modern diesel-powered car making the same journey.

It gets even less politically correct:

Roger Ford, of Modern Railways magazine, said one reason for declining energy efficiency [of trains] was the impact of health and safety and disability access regulations.

Here is a relevant Telegraph article. Here is David Nishimura’s post, my source on this matter. Here is the researcher’s home page. Here is The Transport Blog, perhaps they will offer comment.

N.B.: I have not seen the underlying data, and cannot find the study on the web. In the meantime, for some further revisionism, read Eugene Volokh on the myths of the Cuyahoga River Fire.

Has the Riemann hypothesis in fact been solved?

A French mathematician is claiming to have solved a fiendishly difficult problem, upon which rides a million dollars of prize money. But other mathematicians are sceptical that he has really done it.

On Tuesday, Louis de Branges de Bourcia, a professor of mathematics at Purdue University in Indiana, issued a press release claiming that he has proved the Riemann hypothesis is true.

This proof is perhaps the most tantalising goal in mathematics today. If true, it tells us that prime numbers, which are those exactly divisible only by one and themselves, are scattered utterly randomly along the number line. If not, then mathematicians may be able to predict where the prime numbers fall.

For almost 150 years, mathematicians have been struggling to establish whether or not the Riemann hypothesis holds. And de Branges has claimed to have solved the problem before, only for others to later find flaws in his work.

“For the past 15 years he has been periodically announcing a proof and posting preprints” says Jeffrey Lagarias, a mathematician at AT&T Labs in New Jersey, who has followed de Branges’ work.

Here is the full story.

Courtesy of Jane Galt. The upshot of her post is that the problem is very very hard to solve.

I thought that The Day After Tomorrow, which I saw in Poland, had more bad cliches than perhaps any other movie I have seen, ever. The bad science is actually one of the least ridiculous things about the movie.

Did you know that the film had the widest “day-and-date” release in movie history? (See June 7-13 Variety, p.12.) It topped 108 markets at the same time, in early June. It failed to earn the number one spot in Greece and Serbia, however. Can you guess why?

If it is a collie, perhaps up to 200 words.

The researchers found that Rico knows the names of dozens of play toys and can find the one called for by his owner. That is a vocabulary size about the same as apes, dolphins and parrots trained to understand words, the researchers say.

Since dogs-as-we-know-them co-evolved with humans, I don’t find this surprising. More generally, we underrate the intelligence of many animals. But even I found this part hard to believe:

Rico can even take the next step, figuring out what a new word means.

The researchers put several known toys in a room along with one that Rico had not seen before. From a different room, Rico’s owner asked him to fetch a toy, using a name for the toy the dog had never heard.

The border collie, a breed known primarily for its herding ability, was able to go to the room with the toys and, seven times out of 10, bring back the one he had not seen before. The dog seemingly understood that because he knew the names of all the other toys, the new one must be the one with the unfamiliar name.

Here are some of the words that Rico understands. Keep in mind that this dog understands only German, the text is translated. Note also that most “tricks” (remember Hans the horse?) still represent some form of communication with the animal.

Here is another summary report. And yes, the work is published in the highly respected journal Science, in case you were wondering.

On a related note, I just read (and recommend) this book on how animals talk to each other.

Maybe. Of course there have been false alarms before. The Riemann hypothesis, often considered the greatest unsolved problem in mathematics, concerns whether the distribution of prime numbers has a particular order.

Here is one summary of the problem; here is another, with some more technical links.

You can check out the would-be proof yourself.

Drive as fast as possible. Be aggressive too:

Traffic experts had previously been puzzled as to how Bogotá, with 7 million inhabitants and more than a million private cars, is so jam-free. The answer now seems that Bogotáns are simply more aggressive than their counterparts in London, New York and other huge metropolises.

But why the dare-devil style? Olmos and Muñoz point out that, before improvements to Bogotá’s public-transport and cycling infrastructure, and restrictions on the use of private cars, the city was routinely gridlocked. Perhaps formerly frustrated motorists are now revelling in the open road.

Still, freedom comes at a price, say the researchers: one in six Colombians who die a violent death meet their end in a traffic accident.

I’ve long suspected that something like this would prove true. If you can’t afford to synchronize your lights, just let drivers run them at will. The results also may explain why traffic in Mexico City flows at all.

Here is the original research. Here is an earlier MR post on Colombia.

The picture definition on Japanese camera-phones is now so high that people can stand in a shop, surreptitiously photograph the pages of a magazine and then later read their ill-gotten literature from the screens of their mobile phones.
Japan’s booksellers have risen as one to demand that the Government criminalises this practice…
…the thefts have become more ambitious. Students, for example, are finding that entire textbooks can be photographed and read later at palm-sized convenience.
The publishing industry is suffering badly from the advance of mobile phones in Japan. Where once the train carriages were full of people reading comics or newspapers, passengers now concentrate solely on the screens of their phones. Mobile phone operators say that text-message volumes correspond almost exactly with the commuter rush-hour peaks and troughs.
The latest phones come equipped with a tuner that can — fuzzily — pick up television broadcasts, and several operators have introduced phones with navigation software that shows the user as a moving red blip on an ultra-detailed street atlas of Japan.

That’s from The Times, June 5, 2004, p.2W, no link available. Here is some background information. Here is a related article. Here is a more general article on the illegal downloading of books.

To be continued…

One of my dreams is to go to Niger. In the meantime I will have to be satisfied reading the excellent Sahara: A Natural History, by Marq de Villiers and Sheila Hirtle. No student of spontaneous orders can ignore the following passage:

Obviously [sic], dunes are formed because jumping sand bounces more easily off hard surfaces than off soft ones, so that more sand can be moved over a pebbly desert surface than over a smooth or soft one. Even a slight hollow, though, or a rock, will reduce the amount of sand that the wind can carry, and a small sand patch begins. Very quickly, this patch will trap more sand. When the patch is big enough, it begins to change the wind velocity about it. The winds decrease near the surface and deposit more sand on the patch. Quickly, the dune is built up.

If the conditions are right, the dune will grow rapidly: In days it will be taller than a man, and in just a few weeksit can reach sixty-five or one hundred feet, and keep growing. Over time, the windward slope eventually adjusts itself, and the wind velocity close to the sand increases to compensate for the drag imposed by the sandy surface. The smooth leeward slope steepens until the wind can’t be deflected down sharply enough to follow it, leaving a “dead zone” into which the sand falls. When this so-called dispositional slope reaches the natural slope angel of dry sand (about thirty-two degrees), the added sand cascades down the slope, now called the “slip face.” The dune has stopped growing — there is no gain or loss of sand — though it continues to move forward as a whole, slowly, ponderously, relentlessly.

It turns out that driving on sand is an art, and no one can avoid getting stuck in the long run. Fortunately (to my surprise) most of the surface of the Sahara is rock rather than sand.

Here is a lecture on spontaneous order and sand. Here is advice on how to build a better sand castle.

Every now and then someone is inclined to think that this kind of analysis holds the key to either business cycles or stock market crashes. It has yet to come through, but in the meantime I will keep dreaming of Niger.

Soon we will have cows that are immune to mad cow disease. We’re not about to engineer cows on a large scale, and probably we don’t need to; my interest is in how this upsets the usual spectrum of ecological worries. I’ve found that people who fear mad cow disease also tend to fear genetic engineering of animals. But now, which way to turn? It reminds me of those reports saying we need not fear global warming, because we will run out of oil in the meantime!

Last week, Alex wrote about how smart people live longer. Today, we learn that smart people may be better looking too!

Satoshi Kanazawa of the London School of Economics and his colleague, Jody L. Kovar, assert that beautiful people also tend to be smart people — and vice versa.

In the July issue of Intelligence, the sociologists offer a theory to explain the confluence of beauty and brains. Their argument, in a nutshell: Intelligent men achieve higher status and marry beautiful women, who pass their genes on to their disproportionately attractive and smart kids, who win mates who are good-looking or brainy, and so on. Or at least that’s what they put forth in the journal article, “Why Beautiful People are More Intelligent.”

Here is the full story. Here is a home page for one of the researchers. But wait…he’s the same guy who says that marriage ruins male productivity.

Addendum: I just stumbled upon Randall Parker’s treatment of the same study.

We just found a new one, and it has seven million digits. Here is the bottom line:

Mersenne primes are an especially rare type that take the form 2^p-1, where p is also a prime number. They are named after a 17th Century French monk who first came up with an important conjecture about which values of p would yield a prime. The new number can be represented as 2^(24,036,583)-1. It is the 41st Mersenne prime to have been found.

Here is the full story.

Note also that the number was found by a consortium of private computers, designed to exchange spare computing power:

GIMPS volunteers download a piece of software that runs in the background on their computer. A central server distributes different prime number candidates to each machine, which use spare processing power to test whether it is a genuine prime or not.

Here is more information, plus how to volunteer. Or perhaps you would prefer to search for alien lifeforms.

The universe, that is. New estimates for its size, based on measured microwave radiation, are up to 78 billion light years. And that’s a minimum. The bad news? Given this size, it is less likely that light can “wrap around” an odd-shaped universe, allowing us to see what the earth looked like four billion years ago. And here’s more evidence that the universe is dominated by “dark energy,” causing it to expand, possibly forever.

Take small sips, and spread them out across the day. Don’t start your morning with too much coffee, yeah that means you too. Here is the full analysis, from the ever-insightful Randall Parker. This result reminds me slightly of the Barro-Gordon model of monetary policy. Don’t take your inflation all at once. If you haven’t had some inflation in a while, a mild dose of inflation can provide a nice stimulus.

Read here, to learn why many women prefer prominent cheekbones.