Daily Abstraction

This really is amazing. Be sure to watch all the way through.

(via The Valve)

Here's a wonderful set of alphabet flash cards based on science.

A good post on Terrablog today, about how a two-degree difference in average temperatures, plus an increase in temperature variance, adds up to a significant number of days with record hot temperatures. The best part, though, is the graphic:

Since cancer is the leading cause of death in cats and dogs, and since cats and dogs rarely live beyond 20 years, why don't humans get cancer in their teens?

Via unCLog I came across a paper about predicting future links in social networks -- specifically academic co-authoring. Here's one of the conclusions of the paper:

By running our predictors on some other datasets, we have discovered that performance swells dramatically as the topical focus of the dataset widens. In a narrow field, almost anyone can collaborate with anyone else, and new collaborations are largely random. It would be interesting to make precise a sense in which such new collaborations are simply not predictable from the training data

This makes me wonder whether you could come up with a number that characterizes the amount of link predictability in a given network, and then use that number to make predictions about the future of that network. For example, if the link correlation is low but increasing, maybe that means the field is a small industry that's starting to grow. On the other hand, if the correlation is high and increasing, maybe that means it's a field that's ripe for specialization. Who knows what the implications might be for directing research funding and venture capital?

The most recent issue of physnews has some interesting information about the formation of the early universe. Apparently, new data shows that after "only" three billion years or so, the universe already looked surprisingly old. The standard model of universe formation has trouble explaining these results.

Okay, this is disturbing. Apparently the amount of solar radiation reaching the earth's surface has declined by as much as 10% in only three decades.

Personally, I like cloudy Seattle weather. But it would be rash of me to rejoice in the news that the whole earth may be getting cloudier. After all, someone has to grow tomatoes. One has to wonder what this means with relation to the global warming trend.

(Via ascription is anathema to any enthusiasm)

There's an article at the discovery channel website that describes a paper claiming that the sustainable number of humans is only 6 million -- 1000 times less than the current 6 billion.

But this is clearly ridiculous. A few hundred years ago, there were 30 to 60 million buffalo in North America alone. Buffalo are bigger than us, so clearly North America could sustain at least 30 million humans, not even counting the other continents. We might have to start eating grass, though.

Also, consider that a large percentage of the population of China and India is rural and engaged in subsistence farming. They've been feeding themselves for quite a while, using only local resources. So what reason is there to think that they can't continue to do so? Collectively, those two countries alone have 2.2 billion people. Suppose that only 5% of that is sustainable. That's still 100 million people.

Therefore it seems to me to be a relatively conservative estimate that the world can sustain at least 300 million people, assuming we're all vegetarian, and we kill off all other animals that might compete with us. We might be 20 times overpopulated, but certainly not 1000 times.

I'll file this study in the same category as the flawed ecstasy study where 20% of the subjects died due to heat stroke.

From Nature news:

Trust begets trust - and the hormone oxytocin, research reveals. People's oxytocin levels rise when they receive a signal of trust. Those with the highest hormone levels are more likely to be generous in return and so are more trusting.

I'm very trusting. Sometimes I trust people even when I know for a fact that I'm getting taken advantage of. Maybe my oxytocin level is stuck on high.

I remember when this paper came out in Science, claiming that a "typical night's dose" of ecstasy could cause brain damage. I didn't give it much credence because the study managed to kill 20% of the monkeys they tested on, and two others weren't even given the full dose because they showed signs of severe distress. I simply assumed that this meant that monkeys weren't a good model for human response to ecstasy.

Turns out, the authors of the paper have now retracted it, because the monkeys weren't actually given ecstasy at all. They were given speed.

You would think that a scientist publishing this kind of paper would realize that something just wasn't quite right about their results. You would think that even if the scientist didn't realize something was up, at least the reviewers or editors of the journal would. But the fact is that it's quite common for the large science journals to be less rigorous than you'd expect. They're big because they're popular, and they're popular because they're controversial, not because they're authoritative. The ecstasy paper was published mainly because it was shocking.

Here's a movie of a crow creating and using a tool. In this case it's a piece of wire which the crow bends into a hook so that it can get at some food. The movie is interesting primarily because so many people are surprised that a crow could do such a thing -- they assume that animals are not only incapable of using (much less creating) tools, but that they are also incapable of problem-solving in general.

I find it interesting when people allow their cultural assumptions to leak into the scientific realm like this. It's frequently very difficult to tease apart what you're assuming from what you're actually seeing.

Here's an interesting article about a computer simulation that reproduces segregation. It shows how even relatively unprejudiced people can end up creating highly segregated neighborhoods. It also explores what it takes to prevent genocide in societies with ethnic hostlities.

I read this article about a year ago, and then recently I remembered it but couldn't find it. Now that I've found it again, I'm adding it here so that I don't lose it again.

Science Blog - Meal Skipping Helps Rodents Resist Diabetes, Brain Damage. Mice that only eat every other day may have improved resistance to diabetes and to alzheimer's-style brain disfunction. This is apparently similar to the benefits achieved by calorie restriction, but without actually restricting calorie intake.