The mystery of early puberty

A new study available from the journal Pediatrics (subscription required) shows that girls are entering puberty at steadily younger ages. WebMD explains:

The researchers assessed the onset of puberty by a standard measurement of breast development. They compared the findings to a 1997 study of age of puberty. They found the following in a study of girls aged 6-8:
  • 10.4% of white girls in the current study had breast development, compared to 5% in the 1997 study.
  • 23.4% of African-American girls had breast development, compared to 15.4% in the 1997 study.
The early onset of puberty is found to be correlated with both race and body-mass index (BMI). But what's causing girls to enter puberty sooner?
The researchers also collected urine and blood specimens from the girls to look at levels of compounds called endocrine-disrupting chemicals, Biro says, to see what role these environmental exposures might play in early puberty. ''It appears that some of the endocrine-disrupting chemicals are interacting with body composition and this may be the reason some girls are going into puberty earlier and others later," Biro tells WebMD. "That would have to be speculation," he says of the interaction idea. "But we do know BMI is doing it."

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Hitchens, Prayer, and Decency

Christopher Hitchens has esophageal cancer. He is undergoing chemotherapy. His prognosis is not good, as this is a particularly nasty form of cancer with a low survival rate. It turns out that many people are praying for his recovery, which I find ironic but wonderful. This is, I've been told, what true christianity is supposed to be like---extending the benevolence of your faith to those who might qualify as an enemy. If only all christians were like that. If only those who are like that were the loudest voices. Unfortunately, the screaming meme misanthropic anti-intellectual pre-Enlightenment ignoramus branch of the movement tends to dominate a lot of the discourse, from the supporters of Proposition 8 to those who are not only praying for Hitch to die, but are sending notice of such prayers to public fora and putting megaphone to mouth so as many people as they can blast with their message will hear. [More . . . ]

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Putting our close genetic relationship to chimpanzees into perspective

Genomics Professor Katherine Pollard explored the genetic basis for being human in a video presentation titled "What Makes Us Human. Here a rather dramatic announcement from her talk:

Mouse and rat actually have a common ancestor longer ago than human and chimp, and some people will be surprised by that. They will say, "We are so much more different than a chimp . . . mouse and rat must be pretty similar." Actually mouse and rat on average are much more different from each other than we are from a chimp, and that's sort of a humbling fact to keep in mind.
We're not exactly like chimpanzees, of course, but there are quite a few overlaps (as well as differences), which Pollard explores beginning at the 4-minute mark. Surprisingly, young chimpanzees have a better competency in counting and numbers than young humans. At the 11-minute mark, you can see that the human genome is 95% similar to that of a chimp (or 99%, depending on how you define similarity), and that it is 28% similar (or 89%, depending on definition of similarity) to the genome of a mouse. [More . . . ]

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The real life differences between Christians and non-Christians

Other than attendance at church, how can one tell whether someone is a Christian? In this L.A. Times article, William Lobdell argues that Christian rhetoric often doesn't match up with the actions of those who claim to be Christians.

But judging by the behavior of most Christians, they've become secularists. And the sea of hypocrisy between Christian beliefs and actions is driving Americans away from the institutional church in record numbers.

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Near death experiences as purported evidence of a soul

At AlterNet, Greta Christina has written an article titled, "Why Near-Death Experiences Are a Flimsy Justification for the Idea That We Have Immortal Souls." She argues that the evidence supporting the independent soul is "unfalsifiable."

[It] is flimsy at best. It is unsubstantiated. It comes largely from personal anecdotes. It is internally inconsistent. . . . The evidence supporting the "independent soul" explanation is flimsy at best. It is unsubstantiated. It comes largely from personal anecdotes. It is internally inconsistent. It is shot through with discrepancies. It is loaded with biases and cognitive errors -- especially confirmation bias, the tendency to exaggerate evidence that confirms what we already believe, and to ignore evidence that contradicts it. It has methodological errors that a sixth-grade science project winner could spot in 10 seconds. And that includes the evidence of near-death experiences. There is not a single account of an immaterial soul leaving the body in a near-death experience that meets the gold standard of scientific evidence. Not even close.
Christina bristles at the believer argument that scientists are "biased." Yes, they are, but not in the way that many believers argue:
Scientists are human, too: they don't want to die, and they'd be just as happy as anyone to learn that they were going to live forever.
Christina also points out that the trauma of near death is an altered brain state that can account for any altered perception:
Weird things often happen to people's minds during altered states of consciousness. Exhaustion, stress, distraction, trance-like repetition, optical illusion, sleep deprivation, sensory deprivation, sensory overload... any of these physical changes to the brain, and more, can create vivid "perceptions" that are entirely disconnected from reality. It's been extensively demonstrated. And being near death is an altered state of consciousness, a physical change to the brain.
I agree with Christina's arguments. I would extend them to those who suggest that they can give accurate accounts of what it is like to have a stroke, relying solely on introspection.

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