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  1. 19568

    Your article suggests that the change is an evolutionary process. However, this and the other examples given are all more selective breeding than natural selection. In this case, organisms with undesirable characteristics (smaller size) are overrepresented during reproduction as the result of removing the larger organisms from the breeding population. Robert ArdreyPrescott, Ariz. The tale […]

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  2. Astronomy

    Core Finding: Latest, oddest planet hints at how orbs form

    A newly discovered planet beyond the solar system has the most massive core of any planet known.

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  3. Same Difference: Twins’ gene regulation isn’t identical

    As identical twins go through life, environmental influences differently affect which genes are turned on and which are switched off.

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  4. 19567

    Why slam a copper impactor into Comet Tempel 1? Wouldn’t copper vapor contaminate the spray? Why not a high-temperature ceramic? P.M. deLaubenfelsCorvallis, Ore. According to Casey Lisse of the Deep Impact team, copper was chosen because its density put a lot of mass into a small package, its relative softness reduced bounce at impact, and […]

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  5. Planetary Science

    A Grand Slam

    A 372-kilogram copper projectile released from NASA's Deep Impact spacecraft successfully slammed into Comet Tempel 1 on July 4, producing some heavenly fireworks.

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  6. Math

    Air Transport Central

    The world's air transportation network resembles the Internet.

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  7. Health & Medicine

    Epilepsy surgery stands test of time

    Brain surgery for people with severe epilepsy keeps many of these patients free of seizures for decades.

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  8. Animals

    More junk makes for better dads

    A new analysis links dutiful fatherhood in prairie voles to a stretch of DNA once dismissed as meaningless.

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  9. Astronomy

    Rumblings from a dead star

    The burned-out cinder left behind when a massive Milky Way star exploded recently underwent its own outburst.

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  10. Tech

    A nanoprinter for cheaper diagnostics

    Using strands of DNA as movable type, scientists have created a miniaturized printing technique for mass-producing medical diagnostic chips.

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  11. Health & Medicine

    Stem cell shift may lead to infections, leukemia

    Aging of blood-producing stem cells could be responsible for the relatively high incidence of infections and myeloid leukemia in the elderly.

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  12. 19566

    I have experienced sleep paralysis in almost all of its forms, from terrors to vibrations and auditory hallucinations to out-of-body experiences. Most often it is completely terrifying, but I did have one episode that was elating. Sweet dreams. Kathleen MilroyOntario, Canada The manifestations reported by sufferers of sleep paralysis are eerily similar to the visitation […]

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