Wednesday, December 29, 2010

In the holiday spirit

Lest Spittle-flecked Ire become entirely cantankerous, I'd like to point out one of the best articles I've ever read in the NYT Science section: A Scientist, His Work and a Climate Reckoning.

Lest Spittle-flecked Ire lose it edge, I'd like to point out my only complaint is that when the article states
Later chemical tests, by Dr. Keeling and others, proved that the increase was due to the combustion of fossil fuels.
it does not mention which chemical tests. CO2 produced by burning fossil fuels will have much less Carbon-14 as it comes from sources much older than 6000 years, so the atmospheric ratio of Carbon-14 to Carbon-12 will steadily decrease while [CO2] increases.

However, one must account for a countervailing production of Carbon-14 during the nuclear test era. And there is some neat stuff about relative Carbon-13 depletion involving evolving chemical processes in plants that I just learned about a few minutes ago.

It does help me see why Creationists and the "global warming is a hoax" crowd are natural allies.

Saturday, December 4, 2010

My Rationally Held View of Humans

I borrowed this quote from here.
It appears, therefore, that a swarm's scout bees do something sharply different from what humans do to reach a full agreement in a debate.  Both bees and humans need a group's members to avoid stubbornly supporting their first view, but whereas we humans will usually (and sensibly) give up on a position only after we have learned of a better one, the bees will stop supporting a position automatically.
I do not think that is true at all. Humans rarely give up on their positions*, and are frequently selectively skeptical or easily convinced by data that either confronts or confirms their stubbornly supported first view. 

This is a good short survey pointing to a couple studies of how humans really behave that includes a great quote on this subject by Bertrand Russell:

If a man is offered a fact which goes against his instincts, he will scrutinize it closely, and unless the evidence is overwhelming, he will refuse to believe it. If, on the other hand, he is offered something which affords a reason for acting in accordance to his instincts, he will accept it even on the slightest evidence.
My own favorite quote on this is from Max Planck:
A new scientific truth does not triumph by convincing its opponents and making them see the light, but rather because its opponents eventually die, and a new generation grows up that is familiar with it.

You can just feel the ire.

* Positions, such as this human's view of how humans behave regarding their positions.

Yes, This Again.

The impetus behind this blog was a study that written about in the NYT about an AIDS vaccine. The study was completely inconclusive, yet was promoted as a major advance. Here we go again:
In the study, 2,499 men in six countries — Brazil, Ecuador, Peru, South Africa, Thailand and the United States — were randomly assigned to take either Truvada or a placebo and were followed for up to three years. For ethical reasons, they were also given condoms, treatment for venereal diseases and advice on safe sex. There were 64 infections in the placebo group and 36 in the group that took Truvada, a 44 percent risk reduction.
Two in the Truvada group turned out to have been infected before the study began. When the remaining 34 were tested, only 3 had any drug in their blood — suggesting that the other 31 had not taken their pills.
Different regimens, like taking the pills not daily but only when sex is anticipated, also need testing.
Also, many men in the study failed to take all of their pills, and some clearly lied about it. For example, some who claimed to take them 50 percent or 90 percent of the time had little or no drug in their bloodstreams.
The pills caused no major side effects, though men who began to show signs of liver problems were taken off them quickly. Some men stopped taking the pills because they disliked relatively minor side effects like nausea and headaches. Also, some stopped bothering once they suspected that they might be taking a placebo.
“People have their own reasons,” [Policy Director of amfAR Chris] Collins said. “People don’t take their Lipitor every day either.” 
Again, how hard is it to take sqrt(1250)? But then there's the feckless methodology! Truvada is also apparently effective regardless of the regimen. Imagine that. So is prayer.

I was wondering what is going on with these AIDS studies that keep showing comparably inconclusive results, yet promoting them as breakthroughs. So I went back and looked at the previous study. Then I found this released a month later calling into question that study. And then I realized: all three of these articles were written by the same author, Donald McNeil, and both studies were under funded via the National Institutes of Health infectious diseases director Dr. Anthony Fauci. But this was especially rich:
Putting several biostatistical analyses in a news release “would have confused everybody,” Dr. Fauci said, and suggesting that the researchers were engaging in a cover-up is “absurd.”
Everybody? Statistical analyses are not confusing if they are conclusive; if only one method out of several confirms your hypothesis, your data is not conclusive.

Wednesday, December 1, 2010

Glucose and Aggression ?

The major discovery is that there is a journal called Aggressive Behavior.

Science Daily has reported on a recent work that "Sweetened blood cools hot tempers." The claim is that people who drink lemonade sweetened with sugar show less aggression towards strangers within a short time window after the drink. The experiment is exquisite :

In the study, 62 college students fasted for three hours to reduce glucose instability. They were told they were going to participate in a taste-test study, and then have their reaction times evaluated in a computerized test against an opponent.

Half of the participants were given lemonade sweetened with sugar, while the others were given lemonade with a sugar substitute.

After waiting eight minutes to allow the glucose to be absorbed in their bloodstream, the participants took part in the reaction test.

The reaction test has been used and verified in other studies as a way to measure aggression. Participants were told they and an unseen partner would press a button as fast as possible in 25 trials, and whoever was slower would receive a blast of white noise through their headphones.

At the beginning of each trial, participants set the level of noise their partner would receive if they were slower. The noise was rated on a scale of 1 to 10 -- from 60 decibels to 105 decibels (about the same volume as a smoke alarm).

In actuality, each participant won 12 of the 25 trials (randomly determined).

Aggression was measured by the noise intensity participants chose on the first trial -- before they were provoked by their partner.

Results showed that participants who drank the lemonade sweetened with sugar behaved less aggressively than those who drank lemonade with a sugar substitute. Those who drank the sugar-sweetened beverage chose a noise level averaging 4.8 out of 10, while those with the sugar substitute averaged 6.06.

I can not dispute that a low blood sugar contributes to irritiability (and by extension, aggression.) Just last night, I waited too long between lunch and dinner and was becoming irritated with my surroundings until I was able to eat. But, I have just had a glass of extra-sweetened lemonade and I am still annoyed by the presentation of the study results. The comparison of the means of two populations is meaningless without an error bar on the mean. The numbers of members of each population is only 31, so the error on the mean may be significant relative to the difference of 1.26. Error bars please ! I don't want to pay to see the PDF of this article, so I am not sure if the fault lies with the authors or Science Daily. Did the authors measure their blood sugar? The article's abstract states :

Self-control consumes a lot of glucose in the brain, suggesting that low glucose and poor glucose metabolism are linked to aggression and violence.

Knowing this, it is imperative to know how well each participant metabolizes glucose. Probably more important would be to know the number of men and women in each population. The abstract goes on :

Study 1 found that participants who consumed a glucose beverage behaved less aggressively than did participants who consumed a placebo beverage. Study 2 found an indirect relationship between diabetes (a disorder marked by low glucose levels and poor glucose metabolism) and aggressiveness through low self-control. Study 3 found that states with high diabetes rates also had high violent crime rates. Study 4 found that countries with high rates of glucose-6-phosphate dehydrogenase deficiency (a metabolic disorder related to low glucose levels) also had higher killings rates, both war related and non-war related. All four studies suggest that a spoonful of sugar helps aggressive and violent behaviors go down.

Regarding Study 3 : I wonder what the relative levels of poverty are in these states.