got a favorite screen scraper?

There are more of you reading this now, so I guess I might as well ask again... What's your favorite HTML scraper? I'm feeling the urge to write one, but of course, I'd rather not. It has already been done, again and again, and I'd rather use one of those, but it's not clear whether any of the existing ones actually, you know, work. Any experience with them?

Basically, there are a bunch of sites that I would read if they were on my friends list, but that I generally don't check very often otherwise. Most of them don't have RSS feeds. Rather than waiting for RSS to take over the world, I probably should just hack something up to parse HTML to RSS, with a buttload of special cases for each of the sites I'm interested in. But I keep hoping someone has done it (properly) already. Because I really don't want to.

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good news for worms

Gene tweaking safely doubles lifespan

A US team has doubled the lifespan of the nematode worm with no apparent physiological side effects. The key to what appears to be uncompromised longevity is to silence a gene involved in ageing at just the right point in a worm's life cycle.

In previous work involving interfering with the gene, longer life was only achieved at the cost of a loss of ability to reproduce in C. elegans. "But knocking down the gene after the worms reach adulthood increases their life span without affecting their reproduction," says Cynthia Kenyon at the University of California, San Francisco, who led the research.

The gene, called daf-2, is also found in fruit flies and mice, and Kenyon thinks it is possible that it is present in humans. Interfering with this gene in a similar way might also safely extend the human lifespan, she says.

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But Tom Kirkwood, an expert on ageing at Newcastle University, UK, warns that the apparent absence of reproductive problems in the worms "does not mean longevity has come for free - the trade-off could be more subtle than this. When one looks for evidence of trade-offs, fertility is one of the things involved, but it's not the only one."

Independent pathways

Evolutionary biologists have long predicted that lifespan cannot be lengthened without a reproductive trade off. And in 1993, Kenyon discovered that knocking out the gene, called daf-2, at the point of hatching doubled the worm's normal two-week lifespan. But they were unable to reproduce.

But now her team has shown that if daf-2 is switched off at the onset of adulthood, about four days after birth, the worms live twice as long as normal but reproduce normally.

What is more, if daf-2 is switched off when the worms hatch, then switched back on when they reach adulthood, the worms' life span is not altered but the onset of their fertile period is delayed.

This shows that the daf-2 gene controls reproduction during the worm's developmental phase and lifespan during its adult life. Since the two pathways are independent, there need not be a trade off between them at all, Kenyon argues.

Mario de Bono, who works with nematode worms at the MRC Laboratory of Molecular Biology in Cambridge, UK, welcomes the new findings. "The original daf-2 mutants were fine apart from their inhibited reproduction. If you can rescue this reproductive delay there's no reason why the worms should exhibit other problems," he says.

Journal reference: Science (vol 289, p 830)

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no smoking outdoors, either! ha!

Street smokers fined Y2,000 in central Tokyo

TOKYO -- Tokyo's Chiyoda Ward began levying a 2,000 yen fine Friday on people who smoke or discard cigarette butts on designated streets under a new antismoking ordinance.

As of noon, 13 smokers were ordered to pay the fine, with two paying in cash on the spot. Patrollers also issued warnings to 26 other offenders who said they did not know of the new ordinance, the ward office said.

Offenders showed various reactions; some gave patrollers wry smiles but others seemed to be upset with the new measure. Some offenders refused to take the patrollers' fine ticket, but no serious trouble was reported.

A young woman stopped for smoking on a designated street near the Japan Railways (JR) Kanda Station, told the patrollers, "Will you take responsibility if I am late for work? All I have to do is pay money, right?" She then threw three 10,000 yen bills on the street and walked away.

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The patrollers caught up with her and returned the money, but she refused to accept the notification for her to pay the fine into a designated bank account.

Another man who was approached for smoking on a street in the Kudan district said, "I knew it would start today, but I thought this area was OK." The man paid 2,000 yen, adding "I was unfortunate."

Near JR Akihabara Station, patrollers approached a man throwing a cigarette butt on the street. He begged them not to levy the fine on him, but was told the law must be applied impartially.

The ordinance took effect Oct 1 and ward officials began patrolling eight designated areas near Kanda and Akihabara stations, among other places.

But during the first month, the ward office issued only warnings to offenders, imposing no fines.

It is Japan's first no-smoking ordinance with a penalty.

On Friday, a management level official accompanied each six-person patrol team to try to prevent trouble over the enforcement of fines on the first day, ward officials said.

Patrollers are trained to show their identification cards, explain violations to offenders and politely ask them whether they were aware smoking is banned on the designated streets, the officials said.

In principle, offenders are supposed to pay their fines into a bank account, to prevent people from imitating patrollers, charging fines and pocketing the money.

The officials said that thanks to the ordinance, the number of people smoking on the street is decreasing. But as the fine is nonbinding, unlike the Penal Code, offenders who say they do not know of the ordinance do not have to pay it, the officials said.

The ward office is also considering expanding the no-smoking area, which currently accounts for about 30% of the ward, as most people seem to support the new measure, the officials said. (Kyodo News)


fun facts about solar system simulation

In the bowels of Usenet, John Baez wrote:

Since our solar system has literally thousands of bodies, and since it has lasted for many billions of years, I suppose that we can surmise that relatively stable periodic systems of n-bodies can exist.

When I last checked, the best long-term simulations of the solar system were those of Gerald Sussman and Jack Wisdom of the computer science department at MIT. According to their calculations, the solar system is afflicted with chaos, and its motion can only be predicted with any certainty for about 4 million years... though their simulation went out to 100 million.

Here are some fun facts:

  1. They need to take general relativity into account even for the orbit of Jupiter, which precesses about one radian per billion years.

  2. They take the asteroid belt into account only as modification of the sun's quadrupole moment (which they also use to model its oblateness).

  3. The most worrisome thing about the whole simulation - the most complicated and unpredictable aspect of the whole solar system in terms of its gravitational effects on everything else - is the Earth-Moon system, with its big tidal effects.

  4. The sun loses one Earth mass per 100 million years due to radiation, and another quarter Earth mass due to solar wind.

  5. The first planet to go is Mercury! In their simulations, it eventually picks up energy through a resonance and drifts away.

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Church of Stevie

"I will be delighted to draw you or your loved one with Stevie Nicks."

And if you ask nice, perhaps avphibes will draw your picture with Marilyn Manson...