Galaxy clusters slide
Could the general motion of galaxy clusters (“Galaxy clusters slide to the south,” SN: 10/25/08, p. 12) be evidence of rotational motion of the matter components of the universe on a scale much larger than the observable universe? Would such motion not also result in accelerating expansion of the observable universe, as gravitational attraction opposing rotational expansion weakened as a result of expansion?
Arden Slotter, Castle Pines North, Colo.

“The question of an overall rotation for the universe is an interesting one,” says Glenn Starkman of Case Western Reserve University. “Some attention has been paid to it, but without any convincing evidence to support it. I don’t think this work on large-scale motions particularly encourages interpretation of the motion as rotation. That would require some observation of a coherence to that motion over large swaths of the sky.”Ron Cowen

Treating itch with acupuncture
Concerning “Itch”  (SN: 11/22/08, p. 16 ):  One of the theories behind acupuncture is the interrelation of nerves throughout the body so that stimulation in one area will have an effect on another. Since the researchers have discovered a new network of fibers, albeit itch fibers, it serves to corroborate the existence of a large involved network. This begets the question, is it possible that acupuncture could be a possible treatment for the “itch” or has it been already tried and found ineffective?
Ted Blinder, Havertown, Pa.

To date, acupuncture’s effect on any kind of itch has been addressed by just a few small-scale studies. Clinician Gil Yosipovitch, who treats patients with chronic itch, says that he is a bit skeptical of the benefits of acupuncture for relieving chronic itch. But he adds that some reports of acupuncture’s efficacy for chronic pain make it plausible that itch might also be alleviated. “Bottom line,” Yosipovitch says, “as long as it is done by an expert and is devoid of adverse effects,” it could be used as an adjunct treatment.Laura Sanders


What’s in a name
I thought that Alan Stern’s article (“Debates over definition of planet continue and inspire,” SN: 12/6/08, p. 32) was right on. As a docent at the Detroit Science Center, I have found the lay public to be somewhat confused by the IAU decision. Some visitors to the DSC have even asked what changed about Pluto to cause it to stop being a planet. I explain that nothing changed about the planet itself, that the change in nomenclature was the result of an arbitrary semantic decision. I like Stern’s consideration of a planet to be “any natural object in space that is large enough to be rounded by self-gravity.” This is a definition that people can easily understand, and one that I will quote to visitors as an alternative definition in addition to the one voted on by the IAU. A planet by any other name would be just as round.
Dick Simmons, Clarkston, Mich.

I have no strong feelings on this, but do note that Alan Stern’s complete definition of planet, “any natural object in space that is large enough to be rounded by self-gravity,” emphatically includes the stars.
R. Antonucci, Santa Barbara, Calif.

The sharp-eyed reader is correct; I goofed. Owing to space limitations, I shortened “any natural object in space that is large enough to be rounded by self-gravity, and not sustaining nuclear fusion in its interior” to just what was in the article. I guess I got what I deserved when the reader realized the words now imply something I did not meanthat there is no upper bound to planet size. The fact is, planetary scientists are careful to define planets with both a lower size limit set by the ability to “get round” (and thereby separate from rocks and asteroids), and an upper size limit set by the prohibition against “doing fusion” (and thereby becoming stars).
Alan Stern

The nocebo effect
In “Imagination Medicine” (SN: 12/20/08, p. 26) the author talks about how the placebo effect could be making a drug appear more effective than it really is.  That part of the article made me wonder if the placebo effect could cause an opposite result also:  someone so convinced the medicine would not help them that they did not get better.  Has anyone researched or considered researching this type of “opposite” placebo effect?
Kerry Learned, Plattsburgh, N.Y.

The placebo effect can indeed cause an opposite reaction and that’s called  “the nocebo effect.” Studying the nocebo effect is difficult ethically because doctors would need to tell the patient, “‘Now I’m going to give you a substance that will increase your pain’ but actually give a placebo,” says neuroscientist Fabrizio Benedetti. Research has shown that the nocebo negative effect is due to the activation of a molecule involved in anticipation of anxiety called cholecystokinin. Recent work on nocebo and pain by neuroscientist Jon-Kar Zubieta traced the nocebo effect to the same brain networks responsible for the placebo effect and showed that nocebo worked in opposite ways, to worsen pain rather than relieve it. Zubieta and others say that this reaction is common in many clinical trials.Jeanne Erdmann

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